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revision 1446 by jonathan, Thu Jul 17 14:59:17 2003 UTC revision 2023 by frank, Fri Dec 5 13:54:46 2003 UTC
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1  <?xml version="1.0" encoding="ISO-8859-1"?>  <?xml version="1.0" encoding="ISO-8859-1"?>
2  <!DOCTYPE book  <!DOCTYPE book
3          PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"          PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
4          "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">          "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
5        [<!ENTITY imgscale "60">]>
6  <!-- $Revision$ -->  <!-- $Revision$ -->
7  <book>  <book>
8    <bookinfo>    <bookinfo>
9      <title>Thuban Manual</title>      <title>User's Manual for Thuban 1.0</title>
10      <author>          <authorgroup>
11        <firstname>Jonathan</firstname><surname>Coles</surname>        <author>
12      </author>          <firstname>Jonathan</firstname><surname>Coles</surname>
13      <author>        </author>
14        <firstname>Jan-Oliver</firstname><surname>Wagner</surname>        <author>
15      </author>          <firstname>Jan-Oliver</firstname><surname>Wagner</surname>
16          </author>
17          <author>
18            <firstname>Frank</firstname><surname>Koormann</surname>
19          </author>
20            </authorgroup>
21      <copyright>      <copyright>
22        <year>2003</year>        <year>2003</year>
23        <holder>Intevation GmbH</holder>        <holder>Intevation GmbH</holder>
24      </copyright>      </copyright>
25       <revhistory>
26    <!-- comment this first revision out when releasing a real version -->
27    <!--
28         <revision>
29            <revnumber>CVS version $Id$</revnumber>
30            <date></date>
31            <revremark>Under development.</revremark>
32         </revision>
33    -->
34         <revision>
35            <revnumber>1.0pre3</revnumber>
36            <date>04-Dec-2003</date>
37            <revremark>
38                            Corresponds to Thuban 1.0rc1
39                            New: I18n, right button legend menu, EPSG projectons,
40                PostGIS support.
41                    </revremark>
42         </revision>
43         <revision>
44            <revnumber>1.0pre2</revnumber>
45            <date>29-Aug-2003</date>
46            <revremark>
47                            Corresponds to Thuban development release 0.8.1.
48                            New: chapter on extensions.
49                    </revremark>
50         </revision>
51         <revision>
52            <revnumber>1.0pre1</revnumber>
53            <date>08-Aug-2003</date>
54            <revremark>Corresponds to Thuban development release 0.8.1.</revremark>
55         </revision>
56      </revhistory>
57    
58    </bookinfo>    </bookinfo>
59    
60    <chapter><title>Introduction</title>    <chapter><title>Introduction</title>
61      <para>      <para>
62      Thuban is a Free Software Geographic Information Systems (GIS) viewer.      Thuban is an interactive geographic data viewer.
63      It is being developed because there is currently no simple interactive      It has been developed because there was no simple interactive
64      viewer for geographic information available as Free Software. Thuban is      viewer for geographic information available as Free Software. Thuban is
65      written in Python and C++ and uses the wxWindows library allowing it to      written in Python and C++ and uses the wxWindows library allowing it to
66      run on many different platforms, including GNU/Linux and Windows.      run on many different platforms, including GNU/Linux and Windows.
67      </para>      </para>
68      <para>      <para>
69      GIS viewers are a necessary tool as they allow one to get a visual      Geographic data viewers are a necessary tool as they allow one to
70            get a visual
71      impression of the positional relationship of the information that may not      impression of the positional relationship of the information that may not
72      be apparent from simple inspection of the data values themselves.      be apparent from simple inspection of the data values themselves.
73      Thuban allows the user to create a session that displays      Thuban allows the user to create a session that displays
# Line 44  Line 84 
84          <section><title>Installation</title>          <section><title>Installation</title>
85          <para>          <para>
86          Thuban is actively supported under Debian Testing (sarge), RedHat 7.2,          Thuban is actively supported under Debian Testing (sarge), RedHat 7.2,
87          and Windows 2000. All the necessary files can be found on the          and Windows 2000. Thuban depends on the following packages. These
88            packages can also be found on the
89          <ulink url="http://thuban.intevation.org/download.html">          <ulink url="http://thuban.intevation.org/download.html">
90          Thuban Download site          Thuban Download site
91          </ulink>.          </ulink>.
92            </para>
93            <para>
94            Required:
95            <itemizedlist>
96                <listitem><para>Python 2.2.1 (<literal>http://www.python.org</literal>)</para></listitem>
97                <listitem><para>wxWindows 2.4 (<literal>http://www.wxwindows.org</literal>)</para></listitem>
98                <listitem><para>wxPython 2.4 (<literal>http://www.wxpython.org</literal>)</para></listitem>
99                <listitem><para>proj 4.4.5 Projection Library (<literal>http://www.remotesensing.org/proj/</literal>)</para></listitem>
100                <listitem><para>SQLite 2.8.3 (<literal>http://www.hwaci.com/sw/sqlite/</literal>)</para></listitem>
101                <listitem><para>PySQLite 0.4.3 (<literal>http://pysqlite.sourceforge.net</literal>)</para></listitem>
102            </itemizedlist>
103            </para>
104            <para>
105            Optional:
106            <itemizedlist>
107                <listitem><para>GDAL 1.1.8 (<literal>http://www.remotesensing.org/gdal/</literal>)</para></listitem>
108                <listitem><para>psycopg 1.0.8 (<literal>http://initd.org/software/psycopg</literal>)</para></listitem>
109                </itemizedlist>
110          </para>          </para>
111                    <para>
112                    Along with the source codes, the download page also offers
113                    full installation packages for Debian, Windows and RPM-based systems
114                    (Mandrake, RedHat, SuSE, etc).
115                    </para>
116                    <section><title>RPM-based GNU/Linux Systems</title>
117                            <section><title>Installing Binary Packages</title>
118                                    <para>
119                                    The most wide-spread RPM-based GNU/Linux Systems are RedHat,
120                                    Mandrake and SuSE. The documentation of these distributions
121                                    should contain information about how to install third-party
122                                    RPM packages. Nonetheless, a short summary is provided here.
123                                    </para>
124                                    <para>
125                                    RPM packages can be installed applying several tools.
126                                    The most basic one is the command line program "rpm".
127                                    The hardware architecture is identified in the name
128                                    of RPM packages, eg. 'i386' for most Intel/AMD architectures.
129                                    If you have a different hardware architecture, where no
130                                    binary RPM packages are provided, you must rebuild binary
131                                    packages from the RPM source packages first (see below).
132                                    Typical rpm commands look like:
133    
134                                    <programlisting>
135                                    rpm --install Thuban-0.9.0-1.i386.rpm
136                                    </programlisting>
137    
138                                    Depending on what you already have installed on your
139                                    system, you are informed that some packages are
140                                    required, but not installed. You need to install them
141                                    first. Either they are provided by your GNU/Linux distributor
142                                    or available somewhere on the Internet.
143                                    The more essential and special ones are provided together
144                                    with the Thuban package.
145                                    </para>
146    
147                                    <para>
148                                    For rpm exist some graphical user interfaces, notably
149                                    kpackage, GnoRPM and xrpm.
150                                    </para>
151    
152                                    <para>
153                                    Make yourself familiar with one of the tools and apply it
154                                    to install the packages.
155                                    Note, that you need to be administrator (root) for the system
156                                    to do that.
157                                    </para>
158                            </section>
159                            <section><title>Build Binaries from Source Packages</title>
160                                    <para>
161                                    This section describes howto build RPM install-packages
162                                    from RPM source-packages.
163                                    This adapts and optimizes an install-package specifically
164                                    to your system.
165                                    This is especially helpful to resolve version conflicts of
166                                    dependent packages. Furthermore, install-packages for other
167                                    platforms (e.g. PowerPC) can be created.
168                                    </para>
169    
170                                    <para>
171                                    Note: rpm must be at least version 4. Execute
172                                    <literal>rpm --version</literal> to find out about the version.
173                                    </para>
174    
175                                    <para>
176                                    You need to do the following preparations to be able to
177                                    build the packages as a regular user. You should now
178                                    perform the package buling as root since this
179                                    might cause damage to your system.
180                            <itemizedlist>
181                            <listitem>
182                                                    <para>
183                                                    Create RPM directory structure:
184                                                    Choose a directory (e.g. $HOME/myrpm) and create the
185                                                    subdirectories BUILD, RPM, SOURCES, SPECS and SRPMS.
186                                                    A possible command sequence for this is:
187                                                    <programlisting>
188                                                    mkdir $HOME/freegisrpm
189                                                    cd $HOME/freegisrpm
190                                                    mkdir BUILD RPMS SOURCES SPECS SRPMS
191                                                    </programlisting>
192                                                    </para>
193                                            </listitem>
194                                            <listitem>
195                                                    <para>
196                                                    Set environment variable RPM_DIR:
197                                                    <programlisting>
198                                                    export RPM_DIR=$HOME/freegisrpm
199                                                    </programlisting>
200                                                    </para>
201                                            </listitem>
202                                            <listitem>
203                                                    <para>
204                                                    Create $HOME/.rpmmacros:
205                                                    This file sets general preferences and some
206                                                    specific settings for signing packages.
207                                                    If you don't have a GnuPG-key, you can skip
208                                                    the signature settings i.e. drop the last 4 lines.
209                                                    A signature becomes important when you want to
210                                                    give away packages to third parties.
211                                                    <programlisting>
212    <![CDATA[
213    %packager Name Lastname <[email protected]>
214    
215    %_topdir /home/mylogin/myrpm
216    
217    %_signature gpg
218    %_gpg_name Name Lastname
219    %_pgp_path ~/.gnupg
220    %_pgpbin /usr/bin/gpg
221    ]]>
222                                                    </programlisting>
223                                                    </para>
224                                            </listitem>
225                            </itemizedlist>
226    
227                                    Now you can install any RPM source-package.
228                                    It's components are installed into the corresponding
229                                    subdirectories of your rpm-directory.
230                                    Essentially these are the sources (into directory SOURCES)
231                                    and the so-called spec-file which contains all build
232                                    instructions. The spec-file will go into the SPEC directory.
233                                    Example:
234                                    <literal>rpm --install Thuban-0.9.0-1.src.rpm</literal>
235                                    </para>
236    
237                                    <para>
238                                    Create install-package:
239                                    Go to the directory with the spec-files and rebuild the
240                                    package:
241                                    <programlisting>
242    cd $HOME/mypm/SPECS
243    rpm -bb thuban.spec
244                                    </programlisting>
245                                    Next, you will find the newly created package in
246                                    $HOME/myrpm/RPMS/i386.
247                                    If you build the package for another architecture than
248                                    i386, then the name of the directory has a corresponding name.
249                                    </para>
250                                    <para>
251                                    For documentation of RPM, either type
252                                    <literal>man rpm</literal> or <literal>rpm --help</literal>.
253                                    This will provide you with information on the various command
254                                    line options of RPM.
255                                    For more information see the
256                            <ulink url="http://www.rpm.org/">homepage of RPM</ulink>.
257                                    </para>
258                            </section>
259                    </section>
260          </section>          </section>
261    
262            <section><title>Internationalization</title>
263            <para>
264            Thuban is implemented with internationalization support. So far Thuban
265            is translated by volunteers to the following languages (apart from its
266            main language: English):
267            <itemizedlist>
268                <listitem><para>French</para></listitem>
269                <listitem><para>German</para></listitem>
270                <listitem><para>Italian</para></listitem>
271                <listitem><para>Russian</para></listitem>
272                <listitem><para>Spanish</para></listitem>
273            </itemizedlist>
274            </para>
275    
276            <para>
277            To use internationalization under POSIX systems (like GNU/Linux)
278            you have to set the environment variable LC_ALL accordingly (e.g.
279            LC_ALL=fr_FR for the french language support). Please check your
280            systems documentation for details and supported settings.
281            Specifiying LC_ALL on the command line while launching thuban
282            allows appication specific language settings.
283            </para>
284    
285            <para>
286            MS Windows users have to specify the language to be used via the control
287            bar (which effects all applications).
288            </para>
289            </section>
290    
291          <section><title>The Main Window</title>          <section><title>The Main Window</title>
292          <para>          <para>
293          <screenshot>          <figure>
294          <screeninfo>The Main Window</screeninfo>          <title>The Main Window</title>
295          <mediaobject>          <mediaobject>
296          <imageobject><imagedata fileref="../mainwindow.png" format="PNG"/></imageobject>          <imageobject> <imagedata fileref="../images/1_2_mainwindow.png" format="PNG" scale="&imgscale;"/> </imageobject>
297          <textobject><phrase>The Main Window</phrase></textobject>          <imageobject> <imagedata fileref="./images/1_2_mainwindow.ps" format="EPS" scale="&imgscale;"/> </imageobject>
         <caption><para>The Main Window</para></caption>  
298          </mediaobject>          </mediaobject>
299          </screenshot>          </figure>
300          </para>          </para>
301    
302          <para>          <para>
303          The map window (1) shows the current state of the map and is where          The map window shows the current state of the map and is where
304          the user can interact with the map using the tools.          the user can interact with the map using the tools.
305          </para>          </para>
306    
307          <para>          <para>
308          The legend on          The legend on the left displays a list of the current layers and
309          the left (2) displays a list of the current layers and any visible          any visible classification groups. In the example, each shape layer
310          classification groups. In the example, each shape layer has a default          has a default classification which specifies how the shapes in each
311          classification which specifies how the shapes in each layer are          layer are drawn. Layers that are higher in the list appear
312          drawn. Layers that are higher in the list appear ``closer'' to the          ``closer'' to the user. The legend can be closed by clicking on the
313          user. The legend can be closed by clicking on the small X in the          small X in the upper right-hand region of the legend.
314          upper right-hand region of the legend. To open it again, use          To open it again, use
315          <menuchoice>          <menuchoice>
316          <guimenu>Map</guimenu>          <guimenu>Map</guimenu>
317          <guimenuitem>Legend</guimenuitem>          <guimenuitem>Legend</guimenuitem>
318          </menuchoice>.          </menuchoice>.
319          The legend is also dockable, which means that it can be detached          The legend is also dockable, which means that it can be detached
320          from the main window by clicking on the small button next to the          from the main window by clicking on the small button next to the
321          close button. It can be attached again by clicking the same button          close button. It can be attached by clicking the same button
322          again.          again.
323          </para>          </para>
324          <para>          <para>
325          The status bar (3) displays different information depending on the          The status bar displays different information depending on the
326          current context. If the user is selecting an item from the menu          current context. If the user is selecting an item from the menu
327          then the status bar will display a short help message indicating          then the status bar will display a short help message indicating
328          what each menu item is for. If the user has a tool selected then          what each menu item is for. If the user has a tool selected then
329          the position of the cursor on the map is displayed.          the position of the cursor on the map is displayed.
330          </para>          </para>
331          <para>          <para>
332          The tool bar (4) provides quick access to the commonly needed tools.          The tool bar provides quick access to the commonly needed tools.
333          By hovering over each button the user can see a short messages          By hovering over each button the user can see a short messages
334          describing what the tool does. The tools provided are Zoom In, Zoom          describing what the tool does. The tools provided are Zoom In, Zoom
335          Out, Pan, Full Extent, Full Layer Extent, Full Shape Extent, Indentify,          Out, Pan, Full Extent, Full Layer Extent, Full Shape Extent, Identify,
336          and Label. Each of the tools will be explained in further detail later          and Label. Each of the tools will be explained in further detail later
337          in the manual.          in the manual.
338          </para>          </para>
# Line 112  Line 348 
348          <menuchoice>          <menuchoice>
349          <guimenu>File</guimenu>          <guimenu>File</guimenu>
350          <guimenuitem>New Session</guimenuitem>          <guimenuitem>New Session</guimenuitem>
351          </menuchoice>.          </menuchoice>.
   
352          If a session is already loaded and has been modified without          If a session is already loaded and has been modified without
353          being saved a prompt will ask if the current session should          being saved a prompt will ask if the current session should
354          be saved.          be saved. A new session consists of an empty map with no
355            layers and no tables.
356          </para>          </para>
357          </section>          </section>
358    
# Line 127  Line 362 
362          <menuchoice>          <menuchoice>
363          <guimenu>File</guimenu>          <guimenu>File</guimenu>
364          <guimenuitem>Open Session</guimenuitem>          <guimenuitem>Open Session</guimenuitem>
365          </menuchoice>.          </menuchoice>. A dialog box will open allowing the user to browse
366            for a Thuban Session file. Thuban session files end with
367            <varname>.thuban</varname>. Selecting a file a clicking
368            <guibutton>OK</guibutton> will load the session into Thuban.
369    
370          If a session is already loaded and has been modified without          If a session is already loaded and has been modified without
371          being saved a prompt will ask if the current session should          being saved a prompt will ask if the current session should
# Line 141  Line 379 
379          <menuchoice>          <menuchoice>
380          <guimenu>File</guimenu>          <guimenu>File</guimenu>
381          <guimenuitem>Save Session</guimenuitem>          <guimenuitem>Save Session</guimenuitem>
382          </menuchoice>.          </menuchoice>. A dialog box will open allowing the user to browse
383            the file system and select a place to save the session. Thuban
384            sessions should be saved under a name ending in
385            <varname>.thuban</varname>. If the file already exists the user
386            will be prompted to save under a different name or overwrite the
387            existing file.
388          </para>          </para>
389          </section>          </section>
390    
391          <section><title>The Session Info-Tree</title>          <section><title>The Session Info-Tree</title>
392            <para>
393            <figure>
394            <title>Session Info Tree</title>
395            <mediaobject>
396            <imageobject><imagedata fileref="../images/2_4_session_tree.png" format="PNG" scale="&imgscale;"/></imageobject>
397            <imageobject><imagedata fileref="./images/2_4_session_tree.eps" format="EPS" scale="&imgscale;"/></imageobject>
398            </mediaobject>
399            </figure>
400            </para>
401          <para>          <para>
402                  (primarily for developers)          The session info-tree is primarily intended for developers working
403            with Thuban. It displays many of the internal values for the session,
404            map, and layers. It can be opened from
405            <menuchoice>
406            <guimenu>File</guimenu>
407            <guimenuitem>Session Tree</guimenuitem>
408            </menuchoice>.
409          </para>          </para>
410          </section>          </section>
411    </chapter>    </chapter>
412    
413    <chapter><title>Map Management</title>    <chapter><title>Map Management</title>
414      <para>      <para>
415        The map consists of a number of layers where each layer represents a
416        different type of data set. By interacting with the map the user can
417        visually explore the data.
418        </para>
419        <para>
420        The map can have a name that will appear in the Thuban title bar.
421        The map name can be changed using
422        <menuchoice>
423        <guimenu>Map</guimenu>
424        <guimenuitem>Rename</guimenuitem>
425        </menuchoice>.
426        </para>
427        <para>
428        <inlinemediaobject>
429        <imageobject>
430        <imagedata fileref="../images/3_rename_map.png" format="PNG" scale="&imgscale;"/>
431        </imageobject>
432        <imageobject>
433        <imagedata fileref="./images/3_rename_map.eps" format="EPS" scale="&imgscale;"/>
434        </imageobject>
435        <textobject> <phrase>Rename Map</phrase> </textobject>
436        </inlinemediaobject>
437      </para>      </para>
438    
439          <section><title>Adding and Removing Layers</title>          <section><title>Adding and Removing Layers</title>
440          <para>          <para>
441            There are three types of layers that can be added to a map:
442            Shape layers, database layers
443            and image layers. Shape layers are stored in Shapefile format, a
444            widely used file format for storing geographic objects. These
445            files have the extension ``.shp''. Associated with
446            the shape file is a database file which stores attributes for
447            each shape in the Shape file. This file, in dBase format,
448            has the extension ``.dbf''. Both files must have the same base name.
449            For example, if there is a shape file named roads.shp there must
450            also be a file roads.dbf.
451            </para>
452            <itemizedlist>
453            <listitem>
454            <para>
455            Shape layers can be added to the map with
456            <menuchoice>
457            <guimenu>Map</guimenu>
458            <guimenuitem>Add Layer</guimenuitem>
459            </menuchoice>.
460            Initially, only the ``.shp'' files are shown which is enough for the
461                    selection. However, if you switch to display all files and select one
462                    of the associated files (e.g. ``.dbf''), Thuban will recognize the base
463                    name and load the corresponding Shape file.
464            </para>
465                    <para>
466                    The file dialog for Shape files allows to select multiple files.
467                    Use the shift-button together with the left mouse button to extend
468                    the selection.
469            </para>
470            </listitem>
471    
472            <listitem>
473            <para>Database layers can be added to the map with
474            <menuchoice>
475            <guimenu>Map</guimenu>
476            <guimenuitem>Add Database Layer</guimenuitem>
477            </menuchoice>.
478            A dialog with two is list is opened. The left list displays all
479            database connections currently open for the session. You can retrieve
480            a list of available layers from the selected database which is
481            displayed on the right hand. From this list one layer can be selected,
482            the dialog is closed afterwards.
483          </para>          </para>
484            <para>
485            See appendix ``Working with PostGIS'' for details.
486            </para>
487            </listitem>
488    
489            <listitem>
490            <para>
491            Image layers can be added to the map with
492            <menuchoice>
493            <guimenu>Map</guimenu>
494            <guimenuitem>Add Image Layer</guimenuitem>
495            </menuchoice>.
496            It is important to select a valid image file that has geographic
497            data associated with it. The data can be embedded in the file itself,
498            or in another file. If geographic information cannot be found, Thuban
499            will report an error.
500            </para>
501            </listitem>
502            </itemizedlist>
503          </section>          </section>
504    
505          <section><title>Navigation</title>          <section><title>Navigation</title>
506          <para>          <para>
507            The map can be explored by using the navigation tools available on
508            the tool bar or from the
509            <menuchoice><guimenu>Map</guimenu></menuchoice> menu.
510            </para>
511            <itemizedlist>
512            <listitem>
513            <para>
514            The ZoomIn tool
515            <inlinemediaobject>
516            <imageobject>
517            <imagedata fileref="../images/3_2_zoomin.png" format="PNG" scale="&imgscale;"/>
518            </imageobject>
519            <imageobject>
520            <imagedata fileref="./images/3_2_zoomin.eps" format="EPS" scale="&imgscale;"/>
521            </imageobject>
522            <textobject> <phrase>ZoomIn Tool</phrase> </textobject>
523            </inlinemediaobject>
524            enlarges a region of the map. Clicking once on the map
525            will double the magnification and center the map on the point that
526            was clicked. Clicking and dragging selects a region that will be
527            enlarged to fit the window.
528            </para>
529            </listitem>
530            <listitem>
531            <para>
532            The ZoomOut tool
533            <inlinemediaobject>
534            <imageobject>
535            <imagedata fileref="../images/3_2_zoomout.png" format="PNG" scale="&imgscale;"/>
536            </imageobject>
537            <imageobject>
538            <imagedata fileref="./images/3_2_zoomout.eps" format="EPS" scale="&imgscale;"/>
539            </imageobject>
540            <textobject> <phrase>ZoomOut Tool</phrase> </textobject>
541            </inlinemediaobject>
542            shrinks the map so that a larger region is visible. A single click
543            reduces the magnification by a factor of two. Clicking and dragging
544            selects a box such that the current contents of the window will be
545            scaled to fit into that box.
546            </para>
547            </listitem>
548            <listitem>
549            <para>
550            The Pan tool
551            <inlinemediaobject>
552            <imageobject>
553            <imagedata fileref="../images/3_2_pan.png" format="PNG" scale="&imgscale;"/>
554            </imageobject>
555            <imageobject>
556            <imagedata fileref="./images/3_2_pan.eps" format="EPS" scale="&imgscale;"/>
557            </imageobject>
558            <textobject> <phrase>Pan Tool</phrase> </textobject>
559            </inlinemediaobject>
560            allows the user to move the map around by clicking and dragging.
561            </para>
562            </listitem>
563            <listitem>
564            <para>
565            The Full Extent tool
566            <inlinemediaobject>
567            <imageobject>
568            <imagedata fileref="../images/3_2_fullextent.png" format="PNG" scale="&imgscale;"/>
569            </imageobject>
570            <imageobject>
571            <imagedata fileref="./images/3_2_fullextent.eps" format="EPS" scale="&imgscale;"/>
572            </imageobject>
573            <textobject> <phrase>Full Extent Tool</phrase> </textobject>
574            </inlinemediaobject>
575            rescales the viewable region so that the entire map is visible.
576          </para>          </para>
577            </listitem>
578            <listitem>
579            <para>
580            The Full Layer Extent tool
581            <inlinemediaobject>
582            <imageobject>
583            <imagedata fileref="../images/3_2_fulllayerextent.png" format="PNG" scale="&imgscale;"/>
584            </imageobject>
585            <imageobject>
586            <imagedata fileref="./images/3_2_fulllayerextent.eps" format="EPS" scale="&imgscale;"/>
587            </imageobject>
588            <textobject> <phrase>Full Layer Extent Tool</phrase> </textobject>
589            </inlinemediaobject>
590            rescales the viewable region so that the currently selected
591            layer fits within the window. If no layer is selected this button
592            will be disabled.
593            </para>
594            </listitem>
595            <listitem>
596            <para>
597            The Full Shape Extent tool
598            <inlinemediaobject>
599            <imageobject>
600            <imagedata fileref="../images/3_2_fullshapeextent.png" format="PNG" scale="&imgscale;"/>
601            </imageobject>
602            <imageobject>
603            <imagedata fileref="./images/3_2_fullshapeextent.eps" format="EPS" scale="&imgscale;"/>
604            </imageobject>
605            <textobject> <phrase>Full Shape Extent Tool</phrase> </textobject>
606            </inlinemediaobject>
607            rescales the viewable region so that the currently selected
608            shape fits within the window. If the shape is a point, it is
609            centered and the map is zoomed all the way in. If no shape is
610            selected this button will be disabled. This feature is especially
611            helpful when identifying an object related to a selected record
612            in a tableview (see below).
613    
614            </para>
615            </listitem>
616            </itemizedlist>
617          </section>          </section>
618    
619          <section><title>Object Identification</title>          <section><title>Object Identification</title>
620          <para>          <para>
621            Objects on the map can be identified using the Identify tool
622            <inlinemediaobject>
623            <imageobject>
624            <imagedata fileref="../images/3_3_identify.png" format="PNG" scale="&imgscale;"/>
625            </imageobject>
626            <imageobject>
627            <imagedata fileref="./images/3_3_identify.eps" format="EPS" scale="&imgscale;"/>
628            </imageobject>
629            <textobject> <phrase>Identify Tool</phrase> </textobject>
630            </inlinemediaobject>.
631            Clicking on an object selects that object and opens a dialog which
632            shows all the table attributes for that object. Any current selection
633            is lost. Objects on the map are typically shapes and this document
634            will often refer to objects as shapes.
635          </para>          </para>
636          </section>          </section>
637    
638          <section><title>Object Labelling</title>          <section><title>Object Labeling</title>
639          <para>          <para>
640            Objects can be labeled using the Label tool
641            <inlinemediaobject>
642            <imageobject>
643            <imagedata fileref="../images/3_3_label.png" format="PNG" scale="&imgscale;"/>
644            </imageobject>
645            <imageobject>
646            <imagedata fileref="./images/3_3_label.eps" format="EPS" scale="&imgscale;"/>
647            </imageobject>
648            <textobject> <phrase>Label Tool</phrase> </textobject>
649            </inlinemediaobject>.
650            Clicking on an object selects that object and opens a dialog which
651            displays the table attributes for that object. An attribute can
652            be selected to be the label on the map. The label will be placed
653            at the center of the shape. Clicking on an object that already has
654            a label will remove the label.
655          </para>          </para>
656          </section>          </section>
657    
658          <section><title>The Legend</title>          <section><title>The Legend</title>
659            <para>
660            <inlinemediaobject>
661            <imageobject>
662            <imagedata fileref="../images/3_5_legend.png" format="PNG" scale="&imgscale;"/>
663            </imageobject>
664            <imageobject>
665            <imagedata fileref="./images/3_5_legend.eps" format="EPS" scale="&imgscale;"/>
666            </imageobject>
667            <textobject> <phrase>Legend</phrase> </textobject>
668            </inlinemediaobject>
669            </para>
670          <para>          <para>
671            The Legend provides an overview of the layers in the map. Layers
672            that appear higher in the legend will appear ``closer'' to the user.
673            If a layer supports classification (currently, only shape layers
674            have this feature) then the classification groups will be shown
675            below each layer. The properties for each group are also displayed
676            with a small graphic. Polygon layers appear as rectangles, lines
677            appear as curved lines, and points appear as circles.
678            </para>
679            <para>
680            Along the top of the legend is a toolbar which allows quick access
681            to some of the layer manipulation options under
682            <menuchoice><guimenu>Map</guimenu></menuchoice>.
683            </para>
684    
685            <itemizedlist>
686            <listitem>
687            <para>
688            The Move Layer to Top tool
689            <inlinemediaobject>
690            <imageobject>
691            <imagedata fileref="../images/3_5_totop.png" format="PNG" scale="&imgscale;"/>
692            </imageobject>
693            <imageobject>
694            <imagedata fileref="./images/3_5_totop.eps" format="EPS" scale="&imgscale;"/>
695            </imageobject>
696            <textobject> <phrase>Move Layer to Top</phrase> </textobject>
697            </inlinemediaobject> raises the selected layer to the top of the map.
698            </para>
699            </listitem>
700            <listitem>
701    
702            <para>
703            The Move Layer Up tool
704            <inlinemediaobject>
705            <imageobject>
706            <imagedata fileref="../images/3_5_moveup.png" format="PNG" scale="&imgscale;"/>
707            </imageobject>
708            <imageobject>
709            <imagedata fileref="./images/3_5_moveup.eps" format="EPS" scale="&imgscale;"/>
710            </imageobject>
711            <textobject> <phrase>Move Layer Up</phrase> </textobject>
712            </inlinemediaobject> raises the selected layer one level.
713            </para>
714            </listitem>
715            <listitem>
716    
717            <para>
718            The Move Layer Down tool
719            <inlinemediaobject>
720            <imageobject>
721            <imagedata fileref="../images/3_5_movedown.png" format="PNG" scale="&imgscale;"/>
722            </imageobject>
723            <imageobject>
724            <imagedata fileref="./images/3_5_movedown.eps" format="EPS" scale="&imgscale;"/>
725            </imageobject>
726            <textobject> <phrase>Move Layer Down</phrase> </textobject>
727            </inlinemediaobject> lowers the selected layer one level.
728            </para>
729    
730            </listitem>
731            <listitem>
732            <para>
733            The Move Layer to Bottom tool
734            <inlinemediaobject>
735            <imageobject>
736            <imagedata fileref="../images/3_5_tobottom.png" format="PNG" scale="&imgscale;"/>
737            </imageobject>
738            <imageobject>
739            <imagedata fileref="./images/3_5_tobottom.eps" format="EPS" scale="&imgscale;"/>
740            </imageobject>
741            <textobject> <phrase>Move Layer to Bottom</phrase> </textobject>
742            </inlinemediaobject> lowers the selected layer to the bottom of the map.
743            </para>
744    
745            </listitem>
746            <listitem>
747            <para>
748            The Visible tool
749            <inlinemediaobject>
750            <imageobject>
751            <imagedata fileref="../images/3_5_visible.png" format="PNG" scale="&imgscale;"/>
752            </imageobject>
753            <imageobject>
754            <imagedata fileref="./images/3_5_visible.eps" format="EPS" scale="&imgscale;"/>
755            </imageobject>
756            <textobject> <phrase>Visible</phrase> </textobject>
757            </inlinemediaobject> shows the selected layer in the map if it was
758            hidden.
759            </para>
760    
761            </listitem>
762            <listitem>
763            <para>
764            The Invisible tool
765            <inlinemediaobject>
766            <imageobject>
767            <imagedata fileref="../images/3_5_invisible.png" format="PNG" scale="&imgscale;"/>
768            </imageobject>
769            <imageobject>
770            <imagedata fileref="./images/3_5_invisible.eps" format="EPS" scale="&imgscale;"/>
771            </imageobject>
772            <textobject> <phrase>Invisible</phrase> </textobject>
773            </inlinemediaobject> hides the selected layer in the map.
774            </para>
775    
776            </listitem>
777            <listitem>
778            <para>
779            The Properties tool
780            <inlinemediaobject>
781            <imageobject>
782            <imagedata fileref="../images/3_5_props.png" format="PNG" scale="&imgscale;"/>
783            </imageobject>
784            <imageobject>
785            <imagedata fileref="./images/3_5_props.eps" format="EPS" scale="&imgscale;"/>
786            </imageobject>
787            <textobject> <phrase>Properties</phrase> </textobject>
788            </inlinemediaobject> opens the layer's properties dialog box.
789            Double-clicking on a layer or a group of a layer will open the
790            properties dialog for that layer.
791          </para>          </para>
792            </listitem>
793            </itemizedlist>
794    
795            <para>
796            The most used layer related actions are also available from a
797            popup menu. It is raised when a layer is clicked with the right mouse
798            button.
799            </para>
800            
801            <para>
802            <figure>
803            <title>Layer Popup Menu</title>
804            <mediaobject>
805            <imageobject><imagedata fileref="../images/3_5_popup_menu.png" format="PNG" scale="&imgscale;"/></imageobject>
806            <imageobject><imagedata fileref="./images/3_5_popup_menu.eps" format="EPS" scale="&imgscale;"/></imageobject>
807            </mediaobject>
808            </figure>
809            </para>
810    
811            <para>
812            Along the bottom of the legend is the scalebar. The scalebar
813            will be available if there are any layers and the  map has a
814            projection set.
815            </para>
816            </section>
817    
818            <section><title>Exporting</title>
819            <para>
820            Under Windows, maps can be exported in Enhanced Metafile format
821            (<varname>.wmf</varname>)
822            from
823            <menuchoice>
824            <guimenu>Map</guimenu>
825            <guimenuitem>Export</guimenuitem>
826            </menuchoice> for use in reports, presentations, or further
827            modification. The current map view, legend, and, if available,
828            scalebar are exported. Under other platforms this option is not
829            available. Clicking this menu item open a file selection dialog
830            that lets the user select a location to export the map.
831            </para>
832          </section>          </section>
833    
834          <section><title>Printing</title>          <section><title>Printing</title>
835          <para>          <para>
836            The map can be printed using
837            <menuchoice>
838            <guimenu>Map</guimenu>
839            <guimenuitem>Print</guimenuitem>
840            </menuchoice>. The current map view, legend, and, if available,
841            scalebar are printed. A standard printing dialog will open allowing
842            the user to configure the printer. This dialog will differ depending
843            on which platform Thuban is running.
844          </para>          </para>
845          </section>          </section>
846    
847    </chapter>    </chapter>
848    
849    <chapter><title>Layer Management</title>    <chapter><title>Layer Management</title>
# Line 194  Line 852 
852    
853          <section><title>Types of Layers</title>          <section><title>Types of Layers</title>
854          <para>          <para>
855            There are three types of layers supported by Thuban: shape layers,
856            database layers and
857            image layers. Shape layers consist of vector based shapes with
858            geo-referenced coordinates. There are three types of supported
859            shapes: polygons, lines (arc), and points. Database layers are similar
860            to shape layers but loaded from a database instead of the file system.
861            Image layers can be any image
862            file format supported by the Geo-spatial Data Abstraction Library
863            (GDAL). The images must have geographic
864            coordinate data either embedded within the file or in a separate
865            file that is in the same directory as the image file. GeoTIFF files
866            work very well with Thuban and were designed specifically to be image
867            layers in GIS programs.
868          </para>          </para>
869            <para>
870            All actions in the
871            <menuchoice>
872            <guimenu>Layer</guimenu>
873            </menuchoice> menu act on the currently selected layer in the legend.
874            </para>
875          </section>          </section>
876    
877          <section><title>Visibility</title>          <section><title>Properties</title>
878          <para>          <para>
879            To view the properties for a layer it must first be selected in the
880            legend. The menu option
881            <menuchoice>
882            <guimenu>Layer</guimenu>
883            <guimenuitem>Properties</guimenuitem>
884            </menuchoice> opens a dialog that displays a layer's properties.
885            All layers have a title which can be modified in the text field
886            provided. The type of layer is also shows. If the type is a type
887            of shape (polygon, arc, point) the classification table will be
888            shown. Image layers have no other properties other than title
889            and type.
890            </para>
891            <para>
892            <figure>
893            <title>Properties Window</title>
894            <mediaobject>
895            <imageobject><imagedata fileref="../images/4_2_layer_properties.png" format="PNG" scale="&imgscale;"/></imageobject>
896            <imageobject><imagedata fileref="./images/4_2_layer_properties.eps" format="EPS" scale="&imgscale;"/></imageobject>
897            </mediaobject>
898            </figure>
899            </para>
900            <para>
901            <figure>
902            <title>Properties Window</title>
903            <mediaobject>
904            <imageobject><imagedata fileref="../images/4_2_raster_layer_properties.png" format="PNG" scale="&imgscale;"/></imageobject>
905            <imageobject><imagedata fileref="./images/4_2_raster_layer_properties.eps" format="EPS" scale="&imgscale;"/></imageobject>
906            </mediaobject>
907            </figure>
908          </para>          </para>
909          </section>          </section>
910    
911          <section><title>Sequence</title>          <section><title>Visibility</title>
912          <para>          <para>
913            Sometimes it is not desirable to view all layers at the same time.
914            Some layers may take a long time to draw and so while navigating
915            around the map the user may not want to wait for the map to redraw
916            all the layers each time the map is changed. Each layer can be
917            independently turned on or off using the
918            <menuchoice>
919            <guimenu>Layer</guimenu>
920            <guimenuitem>Show</guimenuitem>
921            </menuchoice>
922            or
923            <menuchoice>
924            <guimenu>Layer</guimenu>
925            <guimenuitem>Hide</guimenuitem>
926            </menuchoice> options respectively.
927          </para>          </para>
928          </section>          </section>
929    
930          <section><title>Duplication</title>          <section><title>Duplication</title>
931          <para>          <para>
932            Layers and all their properties, including classifications, can
933            be duplicated using
934            <menuchoice>
935            <guimenu>Layer</guimenu>
936            <guimenuitem>Duplicate</guimenuitem>
937            </menuchoice>. Duplicating a layer is useful if the user wishes
938            to model a layer in several different ways. Even though the layers
939            overlap, by carefully selecting the shape properties it is possible
940            to display several pieces of information at once. For example, one
941            copy of a roads layer may be classified on a length property and
942            another copy may be classified on a type property. If the length
943            property was expressed with color and the type property expressed
944            with line thickness then it would be possible to view both
945            classifications by placing the type property copy over the
946            length property copy.
947          </para>          </para>
948          </section>          </section>
949    
         <section><title>Properties</title>  
         <para>  
         </para>  
         </section>  
950    </chapter>    </chapter>
951    
952    <chapter><title>Layer Classifications</title>    <chapter><title>Layer Classifications</title>
953      <para>      <para>
954        A layer classification is a way of assigning drawing properties to
955        groups of shapes based on attributes stored in the layer's table.
956        Only layer's with shapes can have a classification; image layers
957        cannot be classified.
958        </para>
959        <para>
960        A classification consists of a number of groups, each group
961        having a value or range of values to match against, and symbol
962        properties which control how a shape is drawn on the map. The user
963        selects which field in the table is used by the classification and
964        when the map is drawn the value for that field for each shape is
965        compared with each group's value. The properties of the first group
966        to match are used to draw the shape. This allows the user to get a
967        visual impression of not only how the data is laid out but also what
968        kind of data lies where.
969        </para>
970        <para>
971        A layer always has a classification. When a new layer is added to the
972        map, a default classification is created with the DEFAULT group. This
973        group cannot be removed but can be hidden (see below). Every shape in the
974        layer, regardless of its attributes, will match this group if no other
975        group matches.
976      </para>      </para>
977    
978          <section><title>Adding and Removing Classes</title>          <section><title>Editing Classifications</title>
979          <para>          <para>
980            A layer's classification can be modified under the properties dialog
981            (<menuchoice>
982            <guimenu>Layer</guimenu>
983            <guimenuitem>Properties</guimenuitem>
984            </menuchoice>). The layer's classification field can be set to None,
985            which simply assigns a DEFAULT group to the classification. No new
986            groups can be added to the classification if the field is None.
987            The user must first select a field to classify on. New groups can
988            be added to the classification with the <guibutton>Add</guibutton>
989            button.
990            </para>
991            <para>
992            To apply the changes to the map the user can click
993            either <guibutton>Try</guibutton> or <guibutton>OK</guibutton>.
994            <guibutton>Try</guibutton> will not close the dialog box, allowing
995            the user to see how the classification changes the map.
996            <guibutton>Revert</guibutton> will undo the last classification applied
997            to the map. <guibutton>OK</guibutton> will commit the changes and
998            close the dialog. The user will be unable to undo the changes.
999            <guibutton>Close</guibutton> simply closes the dialog box. If any
1000            changes have not been applied with <guibutton>Try</guibutton> the
1001            changes will not be applied to the map.
1002            </para>
1003            <para>
1004            <figure>
1005            <title>Properties Window</title>
1006            <mediaobject>
1007            <imageobject><imagedata fileref="../images/5_classification.png" format="PNG" scale="&imgscale;"/></imageobject>
1008            <imageobject><imagedata fileref="./images/5_classification.eps" format="EPS" scale="&imgscale;"/></imageobject>
1009            </mediaobject>
1010            </figure>
1011            </para>
1012            <para>
1013            The order of the groups in the classification is significant
1014            except for the DEFAULT group, which remains at the top. When shapes
1015            are matched against groups the matching begins at the first group
1016            after the DEFAULT group so that groups higher in the list will
1017            be checked first. Matching for a
1018            given shape will stop at the first group that matches. The user can
1019            use <guibutton>Move Up</guibutton> and <guibutton>Move Down</guibutton>
1020            to change the order of the groups. The DEFAULT group will always
1021            match a shape that hasn't matched another group.
1022          </para>          </para>
1023                <section><title>Visible</title>
1024                <para>
1025                The Visible column has check-boxes that determine whether a
1026                classification group will be displayed in the legend. This is
1027                useful if the user knows that the groups completely cover
1028                the data set and don't want the DEFAULT group to be displayed
1029                in the legend and on a printout.
1030                </para>
1031            </section>
1032                <section><title>Symbols</title>
1033                <para>
1034                Each type of shape has its own type of symbol. Thuban supports three
1035                types of shapes: polygons, lines, and points. Polygons and points
1036                have outline and fill color, while lines have only line color. Each
1037                group has associated symbol properties. To edit the symbol
1038                properties for a group the user can double click on the Symbol
1039                column or select a group and click the
1040                <guibutton>Edit Symbol</guibutton> button.
1041                </para>
1042                </section>
1043            <section><title>Value</title>
1044                <para>
1045                The Value column of the classification table is the value that will
1046                be matched when the map is being drawn. The type of data that can
1047                entered into this field depends on the type of data of the
1048                classification field.
1049                </para>
1050                <para>
1051                If the field is of type Text, anything entered
1052                into the field is valid. The text will be compared literally to the
1053                value of the shape attribute, including case sensitivity.
1054                If the type is Integer, then any valid integer may be entered. In
1055                addition, with special syntax, a range of values can be entered.
1056                A range from <varname>start</varname> to <varname>end</varname>
1057                inclusive is specified like this: <literal>[start;end]</literal>.
1058                The exclusive range is specified like this:
1059                <literal>]start;end[</literal>. Ranges can include infinity like
1060                this: <literal>[-oo;oo]</literal>. Field types can also be of type
1061                Decimal. They represent any rational number and can be used in
1062                ranges as well.
1063                </para>
1064                </section>
1065                <section><title>Label</title>
1066                <para>
1067                By default, the text that is displayed for a group in the legend
1068                is the value for that group. The label can substitute a more
1069                descriptive term in the legend.
1070                </para>
1071            </section>
1072          </section>          </section>
1073    
1074          <section><title>Symbols</title>          <section><title>Generating Classes</title>
1075          <para>          <para>
1076            <figure>
1077            <title>Generate Class</title>
1078            <mediaobject>
1079            <imageobject><imagedata fileref="../images/5_3_genclass.png" format="PNG" scale="&imgscale;"/></imageobject>
1080            <imageobject><imagedata fileref="./images/5_3_genclass.eps" format="EPS" scale="&imgscale;"/></imageobject>
1081            </mediaobject>
1082            </figure>
1083          </para>          </para>
         </section>  
   
         <section><title>Generating Classes</title>  
1084          <para>          <para>
1085            Creating a classification by hand can be tedious.
1086            Thuban, therefore, provides a means of generating an entire
1087            classification at once while still giving the user control over
1088            how it appears. Clicking <guibutton>Generate Class</guibutton>
1089            opens the <varname>Generate Classification</varname> dialog.
1090            Under the <varname>Generate</varname> pull down there are at most
1091            three different ways to generate classifications:
1092            Unique Values, Uniform Distribution, and Quantiles. Some options
1093            may not be available if the data type for the field does not
1094            support them. For instance, <varname>Uniform Distribution</varname>
1095            doesn't make sense for a Text field.
1096          </para>          </para>
1097            <para>
1098            For every way of generating a classification, a color scheme must
1099            be selected. Thuban provides several different color schemes that
1100            affect how the group properties change over the classification.
1101            It may be desirable that only certain properties change over the
1102            classification. If the shape type is a polygon or a point then
1103            the <guibutton>Fix Border Color</guibutton> option will be available.
1104            This allows the user to select a border color for all classification
1105            groups.
1106            It is also possible to create a custom color scheme. Selecting
1107            this option will display two symbols: the one of the left has the
1108            properties of the first group and the one on the right has the
1109            properties of the last group. Thuban will interpolate between these
1110            two properties to generate the other groups.
1111            <figure>
1112            <title>Custom Color Scheme</title>
1113            <mediaobject>
1114            <imageobject><imagedata fileref="../images/5_2_custom_ramp.png" format="PNG" scale="&imgscale;"/></imageobject>
1115            <imageobject><imagedata fileref="./images/5_2_custom_ramp.eps" format="EPS" scale="&imgscale;"/></imageobject>
1116            </mediaobject>
1117            </figure>
1118            </para>
1119            <para>
1120            The Unique Values option lets the user select specific values that
1121            appear in the table. Clicking <guibutton>Retrieve From Table</guibutton>
1122            searches the table for all unique values and displays them in the
1123            list on the left. Items can be selected and moved to the list on the
1124            right. Each list can be sorted or reversed for easier searching.
1125            The classification that is generated will be in the same order as
1126            the list on the right.
1127            <figure>
1128            <title>Unique Values</title>
1129            <mediaobject>
1130            <imageobject><imagedata fileref="../images/5_2_unique_values.png" format="PNG" scale="&imgscale;"/></imageobject>
1131            <imageobject><imagedata fileref="./images/5_2_unique_values.eps" format="EPS" scale="&imgscale;"/></imageobject>
1132            </mediaobject>
1133            </figure>
1134            </para>
1135            <para>
1136            The Uniform Distribution option creates a user specified number of
1137            groups of ranges such that each range covers equal intervals. The
1138            minimum and maximum values can automatically be retrieved from the
1139            table by clicking <guibutton>Retrieve From Table</guibutton>. The
1140            stepping is how large each interval is. Adjusting this value will
1141            automatically recalculate how many groups is appropriate.
1142            <figure>
1143            <title>Uniform Distribution</title>
1144            <mediaobject>
1145            <imageobject><imagedata fileref="../images/5_2_uniform_dist.png" format="PNG" scale="&imgscale;"/></imageobject>
1146            <imageobject><imagedata fileref="./images/5_2_uniform_dist.eps" format="EPS" scale="&imgscale;"/></imageobject>
1147            </mediaobject>
1148            </figure>
1149            </para>
1150            <para>
1151            The Quantiles option generates ranges based on the number of items
1152            in the table. For example, by specifying five groups Thuban will
1153            generate five groups with appropriate ranges such that 20% of the table
1154            data is in each group. If it is impossible to generate exact
1155            groupings, Thuban will issue a warning but allow the user to continue.
1156            <figure>
1157            <title>Quantiles</title>
1158            <mediaobject>
1159            <imageobject><imagedata fileref="../images/5_2_quantiles.png" format="PNG" scale="&imgscale;"/></imageobject>
1160            <imageobject><imagedata fileref="./images/5_2_quantiles.eps" format="EPS" scale="&imgscale;"/></imageobject>
1161            </mediaobject>
1162            </figure>
1163            </para>
1164          </section>          </section>
1165    </chapter>    </chapter>
1166    
1167    <chapter><title>Projection Management</title>    <chapter><title>Projection Management</title>
1168      <para>      <para>
1169        Projections control how the geographic data is displayed on the screen.
1170        If multiple layers are loaded into Thuban where the geographic data
1171        is in a different projection system, then the user must specify a
1172        projection for each layer. The user must also tell Thuban which
1173        projection the map is in. This can be the same as the layers or a different
1174        projection in which case the layers are reprojected into that space.
1175        The map projection can be set using
1176        <menuchoice>
1177        <guimenu>Map</guimenu>
1178        <guimenuitem>Projection</guimenuitem>
1179        </menuchoice> and the layer projection can be set using
1180        <menuchoice>
1181        <guimenu>Layer</guimenu>
1182        <guimenuitem>Projection</guimenuitem>
1183        </menuchoice>.
1184        <figure>
1185        <title>Projection Window</title>
1186        <mediaobject>
1187        <imageobject><imagedata fileref="../images/6_projection.png" format="PNG" scale="&imgscale;"/></imageobject>
1188        <imageobject><imagedata fileref="./images/6_projection.eps" format="EPS" scale="&imgscale;"/></imageobject>
1189        </mediaobject>
1190        </figure>
1191        </para>
1192        <para>
1193        Thuban is distributed with a sample collection of projections and the
1194        set of coordinate systems as used by the EPSG
1195        (European Petroleum Survey Group). This quite large set is only displayed
1196        if activated by the according checkbox. The set falls into two parts:
1197        deprecated lists all projections which are no longer part of the
1198        EPSG data base.
1199      </para>      </para>
1200        <para>
1201             The
1202        user can create new projections and make them available to all
1203        future Thuban sessions. They may also be exported and imported so
1204        that custom projections can be distributed.
1205        </para>
1206            <section><title>Selecting a Projection</title>
1207            <para>
1208            The available projections are listed on the left. If the layer
1209            or map already has a projection it will initially be highlighted
1210            and will end with <varname>(current)</varname>. Selecting
1211            <varname>&lt;None&gt;</varname> will cause Thuban to use the data as
1212            it appears in the source file and will not use a projection.
1213            </para>
1214        </section>
1215            <section><title>Editing a Projection</title>
1216            <para>
1217            Whenever a projection is selected from the list its properties
1218            are displayed on the right. These properties can be changed
1219            and the changes saved to the selected projection using
1220            <guibutton>Update</guibutton>. Only a projection that comes
1221            from a file can be updated, so if the current layer's projection
1222            is selected, <guibutton>Update</guibutton> will be disabled.
1223            <guibutton>Add to List</guibutton> adds the projection to the
1224            list of available projections as a new entry, and thus makes it
1225            available to future Thuban sessions. Clicking <guibutton>New</guibutton>
1226            will create an entirely new, empty projection. The
1227            <guibutton>Remove</guibutton> button will permanently remove a
1228            projection from the list of available projections.
1229            </para>
1230            <para>
1231            To apply the selected projection to the map the user can click
1232            either <guibutton>Try</guibutton> or <guibutton>OK</guibutton>.
1233            <guibutton>Try</guibutton> will not close the dialog box, allowing
1234            the user to see how the projeciton changes the map.
1235            <guibutton>Revert</guibutton> will undo the last projection applied
1236            to the map. <guibutton>OK</guibutton> will commit the changes and
1237            close the dialog. The user will be unable to undo the changes.
1238            <guibutton>Close</guibutton> simply closes the dialog box. If no
1239            selection has been applied with <guibutton>Try</guibutton> the
1240            selection will not be applied to the map.
1241            </para>
1242        </section>
1243            <section><title>Importing/Exporting Projections</title>
1244            <para>
1245            The projections that appear in the list of available projections
1246            can be exported to another file that the user chooses. By selecting
1247            one or more projections and clicking <guibutton>Export</guibutton>
1248            the user will be able to select a file in which to store those
1249            projections.
1250            The file can then be distributed to other Thuban users. To import
1251            a projection file the user can click <guibutton>Import</guibutton>.
1252            The imported projections are added to the list and are then available
1253            to the current session and any future Thuban sessions.
1254            </para>
1255        </section>
1256    </chapter>    </chapter>
1257    
1258    <chapter><title>Table Management</title>    <chapter><title>Table Management</title>
1259      <para>      <para>
1260        Thuban distinguishes two different types of tables: Attribute tables
1261        (which belong to a layer) and normal data tables. Both provide
1262            the same general functionality with the difference that actions on an
1263        attribute table might also effect the map display.
1264      </para>      </para>
1265    
1266        <section><title>Table View</title>
1267            <para>
1268            <figure>
1269            <title>Table View</title>
1270            <mediaobject>
1271            <imageobject><imagedata fileref="../images/7_1_table_view.png" format="PNG" scale="&imgscale;"/></imageobject>
1272            <imageobject><imagedata fileref="./images/7_1_table_view.eps" format="EPS" scale="&imgscale;"/></imageobject>
1273            </mediaobject>
1274            </figure>
1275            </para>
1276            <para>
1277            Thuban provides a standard dialog to display table contents, the
1278            Table View. The view has five sections: The title, selections,
1279            the table grid, export functions, and the status bar.
1280            </para>
1281            <para>
1282            The title bar identifies the table with its name.
1283            </para>
1284            <para>
1285            The selections box let the user perform simple analysis on the data
1286            based on comparisons: The first choice must be a field identifier of
1287            the table, the second choice determines the type of comparison. The
1288            third choice can be either a specific value (interpreted as numerical
1289            or string depending on the type of the first field) or a second field
1290            identifier. Thus you can perform analysis like selecting all
1291            records where <literal>population > 10000</literal> or
1292            <literal>cars_per_inhabitant < bikes_per_inhabitant</literal>
1293            (note that the field names are only explanatory, the dBase files
1294            allow only 11 character field names).
1295          
1296            Selections can be combined either by applying a selection only on
1297            a previously selected set of records or by adding the results of a
1298            selection to a previous set. The default is that a selection replaces
1299            earlier results.
1300            </para>
1301            <para>
1302            The table grid shows the contents of the table (one record per row),
1303            with highlighted selection results. Columns and rows can be resized.
1304            </para>
1305            <para>
1306            The contents of a table can be exported into a file, either dBase
1307            format (DBF) or comma separated values (CSV). The
1308            <guibutton>Export</guibutton> button
1309            raises a file dialog to specify a path and file name, the export type
1310            is determined by the file extension (either .dbf or .csv).
1311    
1312            The <guibutton>Export Selection</guibutton> button works similarly
1313            but exports only the selected records.
1314    
1315            The <guibutton>Close</guibutton> button closes the table view window.
1316            This is different from the menu item
1317            <menuchoice>
1318            <guimenu>Table</guimenu>
1319            <guimenuitem>Close</guimenuitem>
1320            </menuchoice> which unloads the table from Thuban.
1321            </para>
1322            <para>
1323            The status bar displays some statistics about the table and optional
1324            selection results.
1325            </para>
1326        </section>
1327    
1328        <section><title>General Functionality (Menu Table)</title>
1329            <para>
1330            The general functions affect all tables open in Thuban. Attribute
1331            tables are considered here as normal data tables (with the exception
1332            that they cannot be closed).
1333            </para>
1334            <section><title>Open</title>
1335                <para>
1336                The
1337                <menuchoice>
1338                <guimenu>Table</guimenu>
1339                <guimenuitem>Open</guimenuitem>
1340                </menuchoice>
1341                item raises a file dialog to let you select a
1342                dBase file from the file system to be loaded into Thuban read-only.
1343                On <guibutton>OK</guibutton> the selected file is loaded and a
1344                table view is opened.
1345                </para>
1346            </section>
1347    
1348            <section><title>Close</title>
1349                <para>
1350                The
1351                <menuchoice>
1352                <guimenu>Table</guimenu>
1353                <guimenuitem>Close</guimenuitem>
1354                </menuchoice>
1355                item raises a dialog listing the currently open
1356                data tables
1357                (loaded via
1358                <menuchoice>
1359                <guimenu>Table</guimenu>
1360                <guimenuitem>Open</guimenuitem>
1361                </menuchoice>). Selected tables are dereferenced on confirmation.
1362                Since tables are opened read-only the contents of the tables are
1363                not affected.
1364    
1365                Any open views of the tables are closed as well.
1366    
1367                Tables used in a join cannot be closed.
1368                </para>
1369            </section>
1370    
1371            <section><title>Rename</title>
1372                <para>
1373                <menuchoice>
1374                <guimenu>Table</guimenu>
1375                <guimenuitem>Rename</guimenuitem>
1376                </menuchoice> changes the table title.
1377                </para>
1378            </section>
1379    
1380            <section><title>Show</title>
1381                <para>
1382                The
1383                <menuchoice>
1384                <guimenu>Table</guimenu>
1385                <guimenuitem>Show</guimenuitem>
1386                </menuchoice>
1387                item raises a list of available tables (explicitly
1388                loaded, attribute tables, results of a join). Selected tables are
1389                show in tables views on <guibutton>OK</guibutton>.
1390                </para>
1391            </section>
1392    
1393            <section><title>Join</title>
1394                <para>
1395                <figure>
1396                <title>Join Tables</title>
1397                <mediaobject>
1398                <imageobject><imagedata fileref="../images/7_2_5_join.png" format="PNG" scale="&imgscale;"/></imageobject>
1399                <imageobject><imagedata fileref="./images/7_2_5_join.eps" format="EPS" scale="&imgscale;"/></imageobject>
1400                </mediaobject>
1401                </figure>
1402                </para>
1403                <para>
1404                The
1405                <menuchoice>
1406                <guimenu>Table</guimenu>
1407                <guimenuitem>Join</guimenuitem>
1408                </menuchoice>
1409                item raises a dialog to specify the two tables to be
1410                joined. The join results in a new table named 'Join of "left table"
1411                and "right table"'.
1412    
1413                The dialog lets you select the two tables to be joined and the two
1414                fields the join has to be performed on. By default, the new
1415                table contains only those records which are matched by the join.
1416    
1417                If you want to preserve the records of the left table you can
1418                perform an outer join. The fields from the right table for records
1419                not matched by the join are filled with <varname>None</varname> in
1420                this case.
1421                </para>
1422            </section>
1423    
1424        </section>
1425        <section><title>Attribute Tables</title>
1426            <para>
1427                To clearly separate between both types of tables (data and
1428            attribute), Thuban provides functionality regarding the attribute
1429            tables under the <menuchoice><guimenu>Layer</guimenu></menuchoice> menu.
1430            </para>
1431    
1432            <section><title>Show Table</title>
1433                <para>
1434                <menuchoice>
1435                <guimenu>Layer</guimenu>
1436                <guimenuitem>Show Table</guimenuitem>
1437                </menuchoice>
1438                opens the attribute table of the currently active layer in a table
1439                view.
1440    
1441                In addition to the functionality described above selections
1442                affect also the map display: objects related to selected records
1443                are highlighted.
1444                </para>
1445            </section>
1446    
1447            <section><title>Join Table</title>
1448                <para>
1449                Unlike the join described above, the join does not result in a
1450                new table. The attribute table of the currently active layer is the
1451                left table and other tables are joined to this table. The results of
1452                the join are available for classification.
1453    
1454                As a consequence, the join cannot result in fewer
1455                records than the source attribute table. The user is warned if the
1456                right table does not fulfill this constraint. An outer join must be
1457                used in such cases.
1458                </para>
1459            </section>
1460    
1461            <section><title>Unjoin Table</title>
1462                <para>
1463                As said above, a normal table cannot be closed while it is still
1464                used in a join. While the joined table resulting from a join of
1465                normal tables can be simply closed (and thereby dereferencing
1466                the source tables), this is not possible for attribute tables.
1467    
1468                Hence joins on attribute tables must be solved explicitly. This is
1469                what the
1470                <menuchoice>
1471                <guimenu>Layer</guimenu>
1472                <guimenuitem>Unjoin Table</guimenuitem>
1473                </menuchoice>
1474                item is used for: The last join for the currently
1475                active layer is solved.
1476                </para>
1477            </section>
1478        </section>
1479      </chapter>
1480    
1481      <chapter><title>Extensions</title>
1482            <para>
1483            Thuban is designed to be extensible. The term Extension is used as a
1484            general term for anything that extends Thuban.
1485            This chapter introduces into some oppportunities how to add and
1486            handle extra functionality developed by your own or third parties.
1487            </para>
1488    
1489            <section><title>Add personal extensions via thubanstart.py</title>
1490                    <para>
1491                    After Thuban has been started for the first time, a directory
1492                    .thuban is created within your home directory.
1493                    There you can add a file thubanstart.py  which will be imported
1494                    by Thuban at start-up. It is recommended to add only import-statements
1495                    to this file to keep the actual code of extensions separate.
1496                    </para>
1497                    <para>
1498                    The modules to import must either be found through the environment
1499                    variable PYTHONPATH or directly be placed into the .thuban-directory.
1500                    </para>
1501                    <para>
1502                    As an example, copy the file examples/simple_extensions/hello_world.py
1503                    of the Thuban source code into the .thuban-directory of your home
1504                    directory. Now add add the statement import hello_world to the
1505                    file thubanstart.py and run Thuban. You will notice an additional
1506                    menu <menuchoice><guimenu>Extensions</guimenu></menuchoice> where
1507                    the new item for the Hello-World extension is placed - select it
1508                    to see the Hello-World message.
1509                    </para>
1510            </section>
1511    
1512            <section><title>Extensions included in Thuban package</title>
1513                    <para>
1514                    The extensions described in this section are part of the
1515                    Thuban package, but not activated by default.
1516                    You will find them in the Thuban installation directory
1517                    under <literal>Extensions/</literal>. Activate them as personal
1518                    extensions via PYTHONPATH as described in the previous section.
1519                    Stable extensions will appear under the menu
1520                    <menuchoice><guimenu>Extensions</guimenu></menuchoice> and
1521                    extensions which are in experimental state and therefore
1522                    not fully functional under
1523                    <menuchoice><guimenu>Experimental</guimenu></menuchoice>.
1524                    </para>
1525    
1526                    <section><title>Stable extensions</title>
1527                            <para>
1528                            These extensions provide extra-functionality to Thuban
1529                            that has not (yet) been integrated in the main application.
1530                            They are considered to be free of bugs, but may be
1531                            further polished with helpful user interactions.
1532                            </para>
1533                            <section><title>gns2shp</title>
1534                                    <para>
1535                                    This tool converts data of the Geospatial Names Server
1536                                    (GNS, see <ulink url="http://www.nima.mil/gns"/>)
1537                                    into Shapefile format.
1538                                    The above web-site offer to download named places
1539                                    information grouped by countries for all of the world
1540                                    except USA for which other data are provided.
1541                                    </para>
1542                                    <para>
1543                                    If you download and unpack a package, you will have
1544                                    a text-file with suffix .txt.
1545                                    Selecting such a file via gns2shp will create the
1546                                    corresponding Shapefile with the same basename and
1547                                    place it in the same direcory. Afterwards it
1548                                    is automatically loaded into Thuban.
1549                                    The Shapefile will not automatically be delete afterwards.
1550                                    </para>
1551                                    <para>
1552                                    The gns2shp.py module can also be executed on the
1553                                    command line for batch processing purposes.
1554                                    </para>
1555                                    <para>
1556                                    A sample (<literal>ls.txt</literal> for Liechtenstein)
1557                                    is included in the directory
1558                                    <literal>Extensions/gns2shp/test</literal>.
1559                                    </para>
1560                            </section>
1561                    </section>
1562                    <section><title>Experimental extensions</title>
1563                            <para>
1564                            All all of these functions have to be handled with care,
1565                            since they are neither complete nor well tested.
1566                            They are to be seen as a proof-of-concept and may
1567                            additionally in some cases of practical help.
1568                            </para>
1569                            <para>
1570                            Any interest on further improvement of these extensions
1571                            should be communicated towards the developer and user
1572                            community.
1573                            </para>
1574    
1575                            <section><title>importAPR</title>
1576                                    <para>
1577                                    This command offer to load an ESRI� ArcView� project
1578                                    file (suffix .apr) and convert it for use within Thuban.
1579                                    After selecting a apr-file to load, a list
1580                                    will be presented that offers to select one of the views
1581                                    of the apr-file, provided there is more than one.
1582                                    Furthermore, the Session Info-Tree is extended with
1583                                    a complete representation of the parsed apr-file.
1584                                    </para>
1585                                    <para>
1586                                    The legend of Thuban does not yet cover all of the elements as
1587                                    supported by the legend of ArcView�. Therefore, the Thuban
1588                                    map will look different. Furthermore, the apr-format is
1589                                    a proprietary format, not openly documented.
1590                                    Therefore, the interpretation is
1591                                    partly based on reverse engeneering and good guessing.
1592                                    </para>
1593                                    <para>
1594                                    The file-paths within the apr-file may not fit and potentially
1595                                    are subject to fix in the apr-file. You can do this
1596                                    applying any text editor. The paths are either absolute
1597                                    or relative from where Thuban has been started.
1598                                    </para>
1599                                    <para>
1600                                    A sample for the Iceland data is included as
1601                                    <literal>Extensions/importAPR/samples/iceland.apr</literal>.
1602                                    The file-paths are relative from the Thuban main directory.
1603                                    </para>
1604                            </section>
1605                    </section>
1606            </section>
1607    
1608            <section><title>Writing simple extensions</title>
1609                    <para>
1610                    Writing an extension for Thuban basically means to
1611                    implement the extra functionality in Python with all of the
1612                    Thuban classes, methods and variables available.
1613                    </para>
1614                    <para>
1615                    All classes and their methods are documented in the source code
1616                    (see their doc-strings). Here is an example from
1617                    Thuban/Model/layer.py that describes some of the methods
1618                    of a Layer object:
1619                    </para>
1620                    <programlisting>
1621                    <![CDATA[
1622    class BaseLayer(TitledObject, Modifiable):
1623    
1624        """Base class for the layers."""
1625    
1626        def __init__(self, title, visible = True, projection = None):
1627            """Initialize the layer.
1628    
1629            title -- the title
1630            visible -- boolean. If true the layer is visible.
1631            """
1632            TitledObject.__init__(self, title)
1633            Modifiable.__init__(self)
1634            self.visible = visible
1635            self.projection = projection
1636    
1637        def Visible(self):
1638            """Return true if layer is visible"""
1639            return self.visible
1640    
1641        def SetVisible(self, visible):
1642            """Set the layer's visibility."""
1643            self.visible = visible
1644            self.issue(LAYER_VISIBILITY_CHANGED, self)
1645    
1646        def HasClassification(self):
1647            """Determine if this layer support classifications."""
1648    ...
1649                    ]]>
1650                    </programlisting>
1651                    <para>
1652                    This example intends to give you an impression of the
1653                    source-code-level documentation.
1654                    You have to make yourself familiar with
1655                    the Python programming language to understand some special
1656                    code elements.
1657                    </para>
1658                    <section><title>hello_world.py</title>
1659                      <para>
1660                      Traditionally, the first example should welcome the world.
1661                      Most of the code handles the frame for integrating a menu
1662                      item into Thuban while the actual raising of a message
1663                      is done in a single line.
1664                      </para>
1665                            <programlisting>
1666                            <![CDATA[
1667    # Copyright (C) 2003 by Intevation GmbH
1668    # Authors:
1669    # Jan-Oliver Wagner <[email protected]>
1670    #
1671    # This program is free software under the GPL (>=v2)
1672    # Read the file COPYING coming with Thuban for details.
1673    
1674    """
1675    Extend Thuban with a sample Hello World to demonstrate simple
1676    extensions.
1677    """
1678    
1679    __version__ = '$Revision$'
1680    
1681    # use _() already now for all strings that may later be translated
1682    from Thuban import _
1683    
1684    # Thuban has named commands which can be registered in the central
1685    # instance registry.
1686    from Thuban.UI.command import registry, Command
1687    
1688    # The instance of the main menu of the Thuban application
1689    # See Thuban/UI/menu.py for the API of the Menu class
1690    from Thuban.UI.mainwindow import main_menu
1691    
1692    def hello_world_dialog(context):
1693        """Just raise a simple dialog to greet the world.
1694    
1695        context -- The Thuban context.
1696        """
1697        context.mainwindow.RunMessageBox(_('Hello World'), _('Hello World!'))
1698    
1699    
1700    # create a new command and register it
1701    registry.Add(Command('hello_world', _('Hello World'), hello_world_dialog,
1702                         helptext = _('Welcome everyone on this planet')))
1703    
1704    # find the extensions menu (create it anew if not found)
1705    extensions_menu = main_menu.find_menu('extensions')
1706    if extensions_menu is None:
1707        extensions_menu = main_menu.InsertMenu('extensions', _('E&xtensions'))
1708    
1709    # finally bind the new command with an entry in the extensions menu
1710    extensions_menu.InsertItem('hello_world')
1711                            ]]>
1712                            </programlisting>
1713                    </section>
1714                    <section><title>Registering a Command</title>
1715                      <para>
1716                      Mainly, our new function has to be registered to the Thuban
1717                      framework in order to connect it to the menu. A registered
1718                      command can also be connected to e.g. a toolbar button.
1719                      </para>
1720                      <para>
1721                      The instances and classes for this are imported at the beginning.
1722                      Any code not inside a method or class is directly executed when
1723                      the source-code module is imported. Therefore, the second
1724                      part of this example consist of the plain statements to create a new
1725                      Command and to add it to the menu.
1726                      </para>
1727                      <para>
1728                      By convention, it looks for a menu registered as ``extensions'' to
1729                      insert the new command. If it does not exist yet, it gets created.
1730                      It is advisable to copy this code for any of your extensions.
1731                      </para>
1732                    </section>
1733                    <section><title>The Thuban context</title>
1734                            <para>
1735                            A registered command that is called, always receives the
1736                            Thuban context. This instance provides our method with
1737                            hook references to all important components of the Thuban
1738                            application.
1739                            </para>
1740                            <para>
1741                    In the example hello_world.py, our function uses the
1742                            mainwindow component which offers a method to raise a
1743                            message dialog. In total there are three hooks:
1744                            <itemizedlist>
1745                            <listitem>
1746                            <para>application:
1747                            This object is the instance of the Thuban Application class.
1748                            Except maybe for loading or savinf sessions, you will not
1749                            need this object for a simple extension.
1750                            See Thuban/UI/application.py for the API.
1751                            </para>
1752                            </listitem>
1753                            <listitem>
1754                            <para>session:
1755                            The instance of the current session. It manages the sessions'
1756                            map and tables. You can set and remove the map or tables.
1757                            In may also get the map object. However, you should know that
1758                            internally it is already prepared to handle many maps.
1759                            Therfore, currently you would always receive a list with exactlty
1760                            one element. In the future, if there are more than one map,
1761                            you will not know which one is the currently display one and
1762                            therefore you should use the mainwindow as hook to find
1763                            the currently displayed map.
1764                            See Thuban/Model/session.py for the API.
1765                            </para>
1766                            </listitem>
1767                            <listitem>
1768                            <para>
1769                            mainwindow: The mainwindow object is central to manage various
1770                            GUI things such as the Legend sub-window. Most notably,
1771                            you get access to the canvas which is the window part where
1772                            the map is drawn. The canvas knows, which map it currently
1773                            draws and therefore you get the current map via
1774                            context.mainwindow.canvas.Map().
1775                            See Thuban/UI/mainwindow.py for the API.
1776                            </para>
1777                            </listitem>
1778                            </itemizedlist>
1779                </para>
1780                    </section>
1781            </section>
1782    </chapter>    </chapter>
1783    
1784    <chapter><title>Trouble Shooting</title>    <chapter><title>Trouble Shooting</title>
1785      <para>      <para>
1786        Here are a few problems that users have encountered when first using Thuban.
1787        </para>
1788        <para>
1789    
1790        <itemizedlist>
1791        <listitem>
1792        <para>After adding two or more layers nothing is drawn in the map window.
1793        </para>
1794        <para>
1795        This is probably because the layers have different projections. Projections
1796        must be set on all layers and on the map itself if the layers' projections
1797        are different.
1798        </para>
1799        </listitem>
1800    
1801        <listitem>
1802        <para>Thuban crashes on startup with the error
1803            <literal>NameError: global name 'False' is not defined</literal>.
1804        </para>
1805        <para>
1806        <varname>True</varname> and <varname>False</varname> were only introduced
1807        in Python 2.2.1. Thuban depends on at least Python 2.2.1.
1808        </para>
1809        </listitem>
1810    
1811        <listitem>
1812        <para>After compiling Thuban, Thuban crashes with an error similar to
1813            <literal>
1814            ImportError: /usr/local//lib/thuban/Thuban/../Lib/wxproj.so: undefined symbol: __gxx_personality_v0
1815            </literal>
1816        </para>
1817        <para>
1818        Thuban depends on the wxWindows library. If Thuban is compiled with an
1819        incompatible version of the compiler than wxWindows was compiled with
1820        this error may occur. Try compiling with a different version of the
1821        compiler.
1822      </para>      </para>
1823        </listitem>
1824        </itemizedlist>
1825        </para>
1826        <para>
1827        If an error occurs Thuban will display a dialog indicating the error
1828        before closing. The text should be copied and reported to the
1829        <ulink url="http://thuban.intevation.org/bugtracker.html">
1830        Intevation bugtracker
1831        </ulink>.
1832        More information about the system is available from
1833        <menuchoice><guimenu>Help</guimenu><guimenuitem>About</guimenuitem></menuchoice> box.
1834        This should also be included in the bug report.
1835        <figure>
1836        <title>Error Dialog</title>
1837        <mediaobject>
1838        <imageobject><imagedata fileref="../images/8_int_error.png" format="PNG" scale="&imgscale;"/></imageobject>
1839        <imageobject><imagedata fileref="./images/8_int_error.eps" format="EPS" scale="&imgscale;"/></imageobject>
1840        </mediaobject>
1841        </figure>
1842        </para>
1843    
1844    </chapter>    </chapter>
1845    
1846    <appendix><title>Supported Data Sources</title>    <appendix><title>Supported Data Sources</title>
1847      <para>      <para>
1848      </para>      </para>
1849        <variablelist>
1850        <varlistentry>
1851        <term>Shapefile</term>
1852        <listitem>
1853            <para>
1854            The Shapefile format has become a standard format for saving
1855            geographic vector information. It supports polygons, lines, and
1856            points.
1857            
1858            <ulink url="http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf">
1859            Technical Specification.
1860            </ulink>  
1861            </para>
1862        </listitem>
1863        </varlistentry>
1864    
1865        <varlistentry>
1866        <term>dBase file</term>
1867        <listitem>
1868            <para>
1869            dBase files are used to store the attributes for each layer. This
1870            is closely associated with the Shapefile format. For detailed
1871            specifications on the correct format of a dBase file used with
1872            Thuban please see the Technical Specification for the Shapefile
1873            format above.
1874            </para>
1875        </listitem>
1876        </varlistentry>
1877    
1878        <varlistentry>
1879        <term>PostGIS</term>
1880        <listitem>
1881            <para>
1882            PostGIS adds support for geographic objects to the PostgreSQL
1883            object-relational database. Different layer types (as for Shapefiles)
1884            are supported. <ulink url="http://postgis.refractions.net">PostGIS
1885            Homepage</ulink>
1886            </para>
1887        </listitem>
1888        </varlistentry>
1889    
1890        <varlistentry>
1891        <term>Raster files</term>
1892        <listitem>
1893            <para>
1894            Binding the GDAL library Thuban supports numerous raster file formats,
1895            see <ulink url="http://www.remotesensing.org/gdal/formats_list.html">
1896            GDAL format list</ulink> for details.</para>
1897    
1898            <para>Most commonly used is the <emphasis>TIFF/GeoTIFF</emphasis>
1899            format: Raster maps are provided as TIFF images, with an additional
1900            "world file" storing the geographic reference (usually with an
1901            extension ".tfw").
1902            </para>
1903        </listitem>
1904        </varlistentry>
1905    
1906        </variablelist>
1907      </appendix>
1908    
1909      <appendix><title>Working with PostGIS</title>
1910      <para>
1911      This section focusses on the use of PostGIS in the Thuban framework. For
1912      installation and maintenance of spatial databases we refer to the  
1913      <ulink url="http://postgis.refractions.net">PostGIS Homepage</ulink>.
1914      The Thuban PostGIS support requires the
1915      <ulink url="http://initd.org/software/psycopg">psycopg module</ulink>.
1916      </para>
1917    
1918      <para>
1919            Working with PostGIS Databases is seperated into two steps:
1920            <itemizedlist>
1921            <listitem><para>Opening a Database Connection</para></listitem>
1922            <listitem><para>Loading a Data Layer</para></listitem>
1923            </itemizedlist>
1924      </para>
1925            <section><title>Opening a Database Connection</title>
1926            <para>
1927                    Before a data layer can be loaded from a PostGIS database a
1928                    connection with the database has to be established.
1929                    <menuchoice>
1930                    <guimenu>Session</guimenu>
1931                    <guimenuitem>Database Connections ...</guimenuitem>
1932                    </menuchoice> opens a dialog for database connection
1933                    management. In the dialog new connections can be added
1934                    and existing ones can be removed. Removing a database
1935                    connection is not possible if the map still displays a
1936                    layer provided by this database connection.
1937            </para>
1938        <figure>
1939        <title>Database Management Dialog</title>
1940        <mediaobject>
1941        <imageobject><imagedata fileref="./images/app_postgis_db_management.png" format="PNG" scale="&imgscale;"/></imageobject>
1942        <imageobject><imagedata fileref="./images/app_postgis_db_management.eps" format="EPS" scale="&imgscale;"/></imageobject>
1943        </mediaobject>
1944        </figure>
1945    
1946            <para>
1947                    To add a new database connection to the session a dialog is
1948                    opened to specify the relevant connection data. Enter all
1949                    data relevant for your connection. If the connection fails
1950                    the dialog remains open and provides some hints on the failure.
1951            </para>
1952            <figure>
1953            <title>Add Database Dialog</title>
1954            <mediaobject>
1955            <imageobject><imagedata fileref="./images/app_postgis_db_add.png" format="PNG" scale="&imgscale;"/></imageobject>
1956            <imageobject><imagedata fileref="./images/app_postgis_db_add.eps" format="EPS" scale="&imgscale;"/></imageobject>
1957            </mediaobject>
1958            </figure>
1959            
1960            <para>
1961            It is important to note that information on database connections are
1962            also stored with the session. Passwords are NOT stored. If you load a
1963            session with database connections you are asked to enter these
1964            passwords again where required.
1965            </para>
1966    
1967            </section>
1968    
1969            <section><title>Loading a Data Layer</title>
1970            <para>
1971            Data layers as part of a map are loaded with the
1972            <menuchoice>
1973            <guimenu>Map</guimenu>
1974            <guimenuitem>Add Database Layer ...</guimenuitem>
1975            </menuchoice> menu item. A dialog is raised displaying two choice
1976            lists. In the left list all connected databases are shown.
1977            Highlighting
1978            one of these and issuing a retrieval results in a list of available
1979            layer tables from that database. After selection of a
1980            layer the dialog is closed.
1981            </para>
1982            <figure>
1983            <title>Add Database Dialog</title>
1984            <mediaobject>
1985            <imageobject><imagedata fileref="./images/app_postgis_add_layer.png" format="PNG" scale="&imgscale;"/></imageobject>
1986            <imageobject><imagedata fileref="./images/app_postgis_add_layer.eps" format="EPS" scale="&imgscale;"/></imageobject>
1987            </mediaobject>
1988            </figure>
1989            
1990            </section>
1991    
1992    </appendix>    </appendix>
1993    
1994    <appendix><title>Supported Projections</title>    <appendix><title>Supported Projections</title>
1995      <para>      <para>
1996        The following types of projections are directly support by
1997        Thuban. The specific values for each are provided by the user
1998        to create custom projections. Thuban comes with predefined
1999        projections which are available through the Projections dialog.
2000        </para>
2001        <itemizedlist>
2002        <listitem>
2003            <para>Geographic</para>
2004            <itemizedlist>
2005            <listitem><para><literal>Ellipsoid</literal></para></listitem>
2006            <listitem><para>
2007                    <literal>Source Data</literal>: either Degrees or Radians
2008                    </para></listitem>
2009            </itemizedlist>
2010        </listitem>
2011        <listitem>
2012            <para>Lambert Conic Conformal</para>
2013        <itemizedlist>
2014            <listitem><para><literal>Ellipsoid</literal></para></listitem>
2015            <listitem><para><literal>Latitude of 1st standard parallel</literal></para></listitem>
2016            <listitem><para><literal>Latitude of 2nd standard parallel</literal></para></listitem>
2017            <listitem><para><literal>Central Meridian</literal></para></listitem>
2018            <listitem><para><literal>Latitude of Origin</literal></para></listitem>
2019            <listitem><para><literal>False Easting</literal> (meters)</para></listitem>
2020            <listitem><para><literal>False Northing</literal> (meters)</para></listitem>
2021        </itemizedlist>
2022        </listitem>
2023        <listitem>
2024            <para>Transverse Mercator</para>
2025        <itemizedlist>
2026            <listitem><para><literal>Ellipsoid</literal></para></listitem>
2027            <listitem><para><literal>Latitude</literal>of origin</para></listitem>
2028            <listitem><para><literal>Longitude</literal>at central meridian</para></listitem>
2029            <listitem><para><literal>Scale Factor</literal>at central meridian</para></listitem>
2030            <listitem><para><literal>False Easting</literal> (meters)</para></listitem>
2031            <listitem><para><literal>False Northing</literal> (meters)</para></listitem>
2032        </itemizedlist>
2033        </listitem>
2034        <listitem>
2035            <para>Universal Transverse Mercator</para>
2036        <itemizedlist>
2037            <listitem><para><literal>Ellipsoid</literal></para></listitem>
2038            <listitem><para><literal>Zone</literal>
2039                    (can be guessed appling the Propose button)</para></listitem>
2040            <listitem><para><literal>Southern Hemisphere</literal> flag</para></listitem>
2041        </itemizedlist>
2042        </listitem>
2043        </itemizedlist>
2044        
2045        <para>
2046        Thuban comes with a sample set of map projections for various
2047        European countries. Apart from the basic projection they differ
2048        especially in their parameterization:
2049        </para>
2050        <itemizedlist>
2051        <listitem><para>Belgium Datum 1972 (Lambert Conic Conformal)</para>
2052        </listitem>
2053    
2054        <listitem><para>Gauss-Boaga Zone 1 (Italy, Transverse Mercartor)</para>
2055        </listitem>
2056    
2057        <listitem><para>Gauss-Krueger Zone 2 (Germany, Transverse Mercartor)
2058        </para>
2059        </listitem>
2060    
2061        <listitem><para>Reseau Geodesique Francaise
2062        (France, Lambert Conic Conformal)</para>
2063        </listitem>
2064    
2065        <listitem><para>UK National Grid (United Kingdom, Transverse Mercartor)
2066        </para>
2067        </listitem>
2068        </itemizedlist>
2069    
2070        <para>
2071        Thuban uses the comprehensive PROJ library for projections. PROJ provides
2072        more than the four commonly used projections described above. If needed
2073        Thuban can be easily extended to a new projection covered by PROJ.
2074      </para>      </para>
2075    </appendix>    </appendix>
2076    
2077  </book>  </book>
2078    

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