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revision 1446 by jonathan, Thu Jul 17 14:59:17 2003 UTC revision 1570 by jan, Fri Aug 8 17:09:02 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 "70">]>
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         <revision>
27            <revnumber>1.0pre1</revnumber>
28            <date>08-Aug-2003</date>
29            <revremark>Corresponds to Thuban development release 0.8.1</revremark>
30         </revision>
31      </revhistory>
32    
33    </bookinfo>    </bookinfo>
34    
35    <chapter><title>Introduction</title>    <chapter><title>Introduction</title>
36      <para>      <para>
37      Thuban is a Free Software Geographic Information Systems (GIS) viewer.      Thuban is an interactive geographic data viewer.
38      It is being developed because there is currently no simple interactive      It has been developed because there was no simple interactive
39      viewer for geographic information available as Free Software. Thuban is      viewer for geographic information available as Free Software. Thuban is
40      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
41      run on many different platforms, including GNU/Linux and Windows.      run on many different platforms, including GNU/Linux and Windows.
42      </para>      </para>
43      <para>      <para>
44      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
45            get a visual
46      impression of the positional relationship of the information that may not      impression of the positional relationship of the information that may not
47      be apparent from simple inspection of the data values themselves.      be apparent from simple inspection of the data values themselves.
48      Thuban allows the user to create a session that displays      Thuban allows the user to create a session that displays
# Line 44  Line 59 
59          <section><title>Installation</title>          <section><title>Installation</title>
60          <para>          <para>
61          Thuban is actively supported under Debian Testing (sarge), RedHat 7.2,          Thuban is actively supported under Debian Testing (sarge), RedHat 7.2,
62          and Windows 2000. All the necessary files can be found on the          and Windows 2000. Thuban depends on the following packages. These
63            packages can also be found on the
64          <ulink url="http://thuban.intevation.org/download.html">          <ulink url="http://thuban.intevation.org/download.html">
65          Thuban Download site          Thuban Download site
66          </ulink>.          </ulink>.
67            <itemizedlist>
68                <listitem><para>Python 2.2.1 (<literal>http://www.python.org</literal>)</para></listitem>
69                <listitem><para>wxWindows 2.4 (<literal>http://www.wxwindows.org</literal>)</para></listitem>
70                <listitem><para>wxPython 2.4 (<literal>http://www.wxpython.org</literal>)</para></listitem>
71                <listitem><para>proj 4.4.5 Projection Library (<literal>http://www.remotesensing.org/proj/</literal>)</para></listitem>
72                <listitem><para>GDAL 1.1.8 (<literal>http://www.remotesensing.org/gdal/</literal>)</para></listitem>
73                <listitem><para>SQLite 2.8.3 (<literal>http://www.hwaci.com/sw/sqlite/</literal>)</para></listitem>
74                <listitem><para>PySQLite 0.4.3 (<literal>http://pysqlite.sourceforge.net</literal>)</para></listitem>
75                </itemizedlist>
76          </para>          </para>
77                    <para>
78                    Along with the source codes, the download page also offers
79                    full installation packages for Debian, Windows and RPM-based systems
80                    (Mandrake, RedHat, SuSE, etc).
81                    </para>
82          </section>          </section>
83    
84          <section><title>The Main Window</title>          <section><title>The Main Window</title>
85          <para>          <para>
86          <screenshot>          <figure>
87          <screeninfo>The Main Window</screeninfo>          <title>The Main Window</title>
88          <mediaobject>          <mediaobject>
89          <imageobject><imagedata fileref="../mainwindow.png" format="PNG"/></imageobject>          <imageobject> <imagedata fileref="../images/1_2_mainwindow.png" format="PNG" scale="&imgscale;"/> </imageobject>
90          <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>  
91          </mediaobject>          </mediaobject>
92          </screenshot>          </figure>
93          </para>          </para>
94    
95          <para>          <para>
96          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
97          the user can interact with the map using the tools.          the user can interact with the map using the tools.
98          </para>          </para>
99    
100          <para>          <para>
101          The legend on          The legend on the left displays a list of the current layers and
102          the left (2) displays a list of the current layers and any visible          any visible classification groups. In the example, each shape layer
103          classification groups. In the example, each shape layer has a default          has a default classification which specifies how the shapes in each
104          classification which specifies how the shapes in each layer are          layer are drawn. Layers that are higher in the list appear
105          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
106          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.
107          upper right-hand region of the legend. To open it again, use          To open it again, use
108          <menuchoice>          <menuchoice>
109          <guimenu>Map</guimenu>          <guimenu>Map</guimenu>
110          <guimenuitem>Legend</guimenuitem>          <guimenuitem>Legend</guimenuitem>
111          </menuchoice>.          </menuchoice>.
112          The legend is also dockable, which means that it can be detached          The legend is also dockable, which means that it can be detached
113          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
114          close button. It can be attached again by clicking the same button          close button. It can be attached by clicking the same button
115          again.          again.
116          </para>          </para>
117          <para>          <para>
118          The status bar (3) displays different information depending on the          The status bar displays different information depending on the
119          current context. If the user is selecting an item from the menu          current context. If the user is selecting an item from the menu
120          then the status bar will display a short help message indicating          then the status bar will display a short help message indicating
121          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
122          the position of the cursor on the map is displayed.          the position of the cursor on the map is displayed.
123          </para>          </para>
124          <para>          <para>
125          The tool bar (4) provides quick access to the commonly needed tools.          The tool bar provides quick access to the commonly needed tools.
126          By hovering over each button the user can see a short messages          By hovering over each button the user can see a short messages
127          describing what the tool does. The tools provided are Zoom In, Zoom          describing what the tool does. The tools provided are Zoom In, Zoom
128          Out, Pan, Full Extent, Full Layer Extent, Full Shape Extent, Indentify,          Out, Pan, Full Extent, Full Layer Extent, Full Shape Extent, Identify,
129          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
130          in the manual.          in the manual.
131          </para>          </para>
# Line 112  Line 141 
141          <menuchoice>          <menuchoice>
142          <guimenu>File</guimenu>          <guimenu>File</guimenu>
143          <guimenuitem>New Session</guimenuitem>          <guimenuitem>New Session</guimenuitem>
144          </menuchoice>.          </menuchoice>.
   
145          If a session is already loaded and has been modified without          If a session is already loaded and has been modified without
146          being saved a prompt will ask if the current session should          being saved a prompt will ask if the current session should
147          be saved.          be saved. A new session consists of an empty map with no
148            layers and no tables.
149          </para>          </para>
150          </section>          </section>
151    
# Line 127  Line 155 
155          <menuchoice>          <menuchoice>
156          <guimenu>File</guimenu>          <guimenu>File</guimenu>
157          <guimenuitem>Open Session</guimenuitem>          <guimenuitem>Open Session</guimenuitem>
158          </menuchoice>.          </menuchoice>. A dialog box will open allowing the user to browse
159            for a Thuban Session file. Thuban session files end with
160            <varname>.thuban</varname>. Selecting a file a clicking
161            <guibutton>OK</guibutton> will load the session into Thuban.
162    
163          If a session is already loaded and has been modified without          If a session is already loaded and has been modified without
164          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 172 
172          <menuchoice>          <menuchoice>
173          <guimenu>File</guimenu>          <guimenu>File</guimenu>
174          <guimenuitem>Save Session</guimenuitem>          <guimenuitem>Save Session</guimenuitem>
175          </menuchoice>.          </menuchoice>. A dialog box will open allowing the user to browse
176            the file system and select a place to save the session. Thuban
177            sessions should be saved under a name ending in
178            <varname>.thuban</varname>. If the file already exists the user
179            will be prompted to save under a different name or overwrite the
180            existing file.
181          </para>          </para>
182          </section>          </section>
183    
184          <section><title>The Session Info-Tree</title>          <section><title>The Session Info-Tree</title>
185            <para>
186            <figure>
187            <title>Session Info Tree</title>
188            <mediaobject>
189            <imageobject><imagedata fileref="../images/2_4_session_tree.png" format="PNG" scale="&imgscale;"/></imageobject>
190            <imageobject><imagedata fileref="./images/2_4_session_tree.eps" format="EPS" scale="&imgscale;"/></imageobject>
191            </mediaobject>
192            </figure>
193            </para>
194          <para>          <para>
195                  (primarily for developers)          The session info-tree is primarily intended for developers working
196            with Thuban. It displays many of the internal values for the session,
197            map, and layers. It can be opened from
198            <menuchoice>
199            <guimenu>File</guimenu>
200            <guimenuitem>Session Tree</guimenuitem>
201            </menuchoice>.
202          </para>          </para>
203          </section>          </section>
204    </chapter>    </chapter>
205    
206    <chapter><title>Map Management</title>    <chapter><title>Map Management</title>
207      <para>      <para>
208        The map consists of a number of layers where each layer represents a
209        different type of data set. By interacting with the map the user can
210        visually explore the data.
211        </para>
212        <para>
213        The map can have a name that will appear in the Thuban title bar.
214        The map name can be changed using
215        <menuchoice>
216        <guimenu>Map</guimenu>
217        <guimenuitem>Rename</guimenuitem>
218        </menuchoice>.
219        </para>
220        <para>
221        <inlinemediaobject>
222        <imageobject>
223        <imagedata fileref="../images/3_rename_map.png" format="PNG" scale="&imgscale;"/>
224        </imageobject>
225        <imageobject>
226        <imagedata fileref="./images/3_rename_map.eps" format="EPS" scale="&imgscale;"/>
227        </imageobject>
228        <textobject> <phrase>Rename Map</phrase> </textobject>
229        </inlinemediaobject>
230      </para>      </para>
231    
232          <section><title>Adding and Removing Layers</title>          <section><title>Adding and Removing Layers</title>
233          <para>          <para>
234            There are two types of layers that can be added to a map: shape layers
235            and image layers. Shape layers are stored in Shapefile format, a
236            standard file format for storing geographic objects. These
237            files have the extension ``.shp''. Associated with
238            the shape file is a database file which stores attributes for
239            each shape in the shape file. This file, in dBase format,
240            has the extension ``.dbf''. Both files must have the same base name.
241            For example, if there is a shape file named roads.shp there must
242            also be a file roads.dbf.
243            </para>
244            <para>
245            Shape layers can be added to the map with
246            <menuchoice>
247            <guimenu>Map</guimenu>
248            <guimenuitem>Add Layer</guimenuitem>
249            </menuchoice>.
250            Thuban will load all files with the same base name, so it doesn't
251            matter if the shape file or database file is selected.
252            </para>
253    
254            <para>
255            Image layers can be added to the map with
256            <menuchoice>
257            <guimenu>Map</guimenu>
258            <guimenuitem>Add Image Layer</guimenuitem>
259            </menuchoice>.
260            It is important to select a valid image file that has geographic
261            data associated with it. The data can be embedded in the file itself,
262            or in another file. If geographic information cannot be found, Thuban
263            will report an error.
264          </para>          </para>
265          </section>          </section>
266    
267          <section><title>Navigation</title>          <section><title>Navigation</title>
268          <para>          <para>
269            The map can be explored by using the navigation tools available on
270            the tool bar or from the
271            <menuchoice><guimenu>Map</guimenu></menuchoice> menu.
272            </para>
273            <itemizedlist>
274            <listitem>
275            <para>
276            The ZoomIn tool
277            <inlinemediaobject>
278            <imageobject>
279            <imagedata fileref="../images/3_2_zoomin.png" format="PNG" scale="&imgscale;"/>
280            </imageobject>
281            <imageobject>
282            <imagedata fileref="./images/3_2_zoomin.eps" format="EPS" scale="&imgscale;"/>
283            </imageobject>
284            <textobject> <phrase>ZoomIn Tool</phrase> </textobject>
285            </inlinemediaobject>
286            enlarges a region of the map. Clicking once on the map
287            will double the magnification and center the map on the point that
288            was clicked. Clicking and dragging selects a region that will be
289            enlarged to fit the window.
290            </para>
291            </listitem>
292            <listitem>
293            <para>
294            The ZoomOut tool
295            <inlinemediaobject>
296            <imageobject>
297            <imagedata fileref="../images/3_2_zoomout.png" format="PNG" scale="&imgscale;"/>
298            </imageobject>
299            <imageobject>
300            <imagedata fileref="./images/3_2_zoomout.eps" format="EPS" scale="&imgscale;"/>
301            </imageobject>
302            <textobject> <phrase>ZoomOut Tool</phrase> </textobject>
303            </inlinemediaobject>
304            shrinks the map so that a larger region is visible. A single click
305            reduces the magnification by a factor of two. Clicking and dragging
306            selects a box such that the current contents of the window will be
307            scaled to fit into that box.
308            </para>
309            </listitem>
310            <listitem>
311            <para>
312            The Pan tool
313            <inlinemediaobject>
314            <imageobject>
315            <imagedata fileref="../images/3_2_pan.png" format="PNG" scale="&imgscale;"/>
316            </imageobject>
317            <imageobject>
318            <imagedata fileref="./images/3_2_pan.eps" format="EPS" scale="&imgscale;"/>
319            </imageobject>
320            <textobject> <phrase>Pan Tool</phrase> </textobject>
321            </inlinemediaobject>
322            allows the user to move the map around by clicking and dragging.
323            </para>
324            </listitem>
325            <listitem>
326            <para>
327            The Full Extent tool
328            <inlinemediaobject>
329            <imageobject>
330            <imagedata fileref="../images/3_2_fullextent.png" format="PNG" scale="&imgscale;"/>
331            </imageobject>
332            <imageobject>
333            <imagedata fileref="./images/3_2_fullextent.eps" format="EPS" scale="&imgscale;"/>
334            </imageobject>
335            <textobject> <phrase>Full Extent Tool</phrase> </textobject>
336            </inlinemediaobject>
337            rescales the viewable region so that the entire map is visible.
338            </para>
339            </listitem>
340            <listitem>
341            <para>
342            The Full Layer Extent tool
343            <inlinemediaobject>
344            <imageobject>
345            <imagedata fileref="../images/3_2_fulllayerextent.png" format="PNG" scale="&imgscale;"/>
346            </imageobject>
347            <imageobject>
348            <imagedata fileref="./images/3_2_fulllayerextent.eps" format="EPS" scale="&imgscale;"/>
349            </imageobject>
350            <textobject> <phrase>Full Layer Extent Tool</phrase> </textobject>
351            </inlinemediaobject>
352            rescales the viewable region so that the currently selected
353            layer fits within the window. If no layer is selected this button
354            will be disabled.
355          </para>          </para>
356            </listitem>
357            <listitem>
358            <para>
359            The Full Shape Extent tool
360            <inlinemediaobject>
361            <imageobject>
362            <imagedata fileref="../images/3_2_fullshapeextent.png" format="PNG" scale="&imgscale;"/>
363            </imageobject>
364            <imageobject>
365            <imagedata fileref="./images/3_2_fullshapeextent.eps" format="EPS" scale="&imgscale;"/>
366            </imageobject>
367            <textobject> <phrase>Full Shape Extent Tool</phrase> </textobject>
368            </inlinemediaobject>
369            rescales the viewable region so that the currently selected
370            shape fits within the window. If the shape is a point, it is
371            centered and the map is zoomed all the way in. If no shape is
372            selected this button will be disabled. This feature is especially
373            helpful when identifying an object related to a selected record
374            in a tableview (see below).
375    
376            </para>
377            </listitem>
378            </itemizedlist>
379          </section>          </section>
380    
381          <section><title>Object Identification</title>          <section><title>Object Identification</title>
382          <para>          <para>
383            Objects on the map can be identified using the Identify tool
384            <inlinemediaobject>
385            <imageobject>
386            <imagedata fileref="../images/3_3_identify.png" format="PNG" scale="&imgscale;"/>
387            </imageobject>
388            <imageobject>
389            <imagedata fileref="./images/3_3_identify.eps" format="EPS" scale="&imgscale;"/>
390            </imageobject>
391            <textobject> <phrase>Identify Tool</phrase> </textobject>
392            </inlinemediaobject>.
393            Clicking on an object selects that object and opens a dialog which
394            shows all the table attributes for that object. Any current selection
395            is lost. Objects on the map are typically shapes and this document
396            will often refer to objects as shapes.
397          </para>          </para>
398          </section>          </section>
399    
400          <section><title>Object Labelling</title>          <section><title>Object Labeling</title>
401          <para>          <para>
402            Objects can be labeled using the Label tool
403            <inlinemediaobject>
404            <imageobject>
405            <imagedata fileref="../images/3_3_label.png" format="PNG" scale="&imgscale;"/>
406            </imageobject>
407            <imageobject>
408            <imagedata fileref="./images/3_3_label.eps" format="EPS" scale="&imgscale;"/>
409            </imageobject>
410            <textobject> <phrase>Label Tool</phrase> </textobject>
411            </inlinemediaobject>.
412            Clicking on an object selects that object and opens a dialog which
413            displays the table attributes for that object. An attribute can
414            be selected to be the label on the map. The label will be placed
415            at the center of the shape. Clicking on an object that already has
416            a label will remove the label.
417          </para>          </para>
418          </section>          </section>
419    
420          <section><title>The Legend</title>          <section><title>The Legend</title>
421            <para>
422            <inlinemediaobject>
423            <imageobject>
424            <imagedata fileref="../images/3_5_legend.png" format="PNG" scale="&imgscale;"/>
425            </imageobject>
426            <imageobject>
427            <imagedata fileref="./images/3_5_legend.eps" format="EPS" scale="&imgscale;"/>
428            </imageobject>
429            <textobject> <phrase>Legend</phrase> </textobject>
430            </inlinemediaobject>
431            </para>
432          <para>          <para>
433            The Legend provides an overview of the layers in the map. Layers
434            that appear higher in the legend will appear ``closer'' to the user.
435            If a layer supports classification (currently, only shape layers
436            have this feature) then the classification groups will be shown
437            below each layer. The properties for each group are also displayed
438            with a small graphic. Polygon layers appear as rectangles, lines
439            appear as curved lines, and points appear as circles.
440            </para>
441            <para>
442            Along the top of the legend is a toolbar which allows quick access
443            to some of the layer manipulation options under
444            <menuchoice><guimenu>Map</guimenu></menuchoice>.
445            </para>
446    
447            <itemizedlist>
448            <listitem>
449            <para>
450            The Move Layer to Top tool
451            <inlinemediaobject>
452            <imageobject>
453            <imagedata fileref="../images/3_5_totop.png" format="PNG" scale="&imgscale;"/>
454            </imageobject>
455            <imageobject>
456            <imagedata fileref="./images/3_5_totop.eps" format="EPS" scale="&imgscale;"/>
457            </imageobject>
458            <textobject> <phrase>Move Layer to Top</phrase> </textobject>
459            </inlinemediaobject> raises the selected layer to the top of the map.
460            </para>
461            </listitem>
462            <listitem>
463    
464            <para>
465            The Move Layer Up tool
466            <inlinemediaobject>
467            <imageobject>
468            <imagedata fileref="../images/3_5_moveup.png" format="PNG" scale="&imgscale;"/>
469            </imageobject>
470            <imageobject>
471            <imagedata fileref="./images/3_5_moveup.eps" format="EPS" scale="&imgscale;"/>
472            </imageobject>
473            <textobject> <phrase>Move Layer Up</phrase> </textobject>
474            </inlinemediaobject> raises the selected layer one level.
475            </para>
476            </listitem>
477            <listitem>
478    
479            <para>
480            The Move Layer Down tool
481            <inlinemediaobject>
482            <imageobject>
483            <imagedata fileref="../images/3_5_movedown.png" format="PNG" scale="&imgscale;"/>
484            </imageobject>
485            <imageobject>
486            <imagedata fileref="./images/3_5_movedown.eps" format="EPS" scale="&imgscale;"/>
487            </imageobject>
488            <textobject> <phrase>Move Layer Down</phrase> </textobject>
489            </inlinemediaobject> lowers the selected layer one level.
490            </para>
491    
492            </listitem>
493            <listitem>
494            <para>
495            The Move Layer to Bottom tool
496            <inlinemediaobject>
497            <imageobject>
498            <imagedata fileref="../images/3_5_tobottom.png" format="PNG" scale="&imgscale;"/>
499            </imageobject>
500            <imageobject>
501            <imagedata fileref="./images/3_5_tobottom.eps" format="EPS" scale="&imgscale;"/>
502            </imageobject>
503            <textobject> <phrase>Move Layer to Bottom</phrase> </textobject>
504            </inlinemediaobject> lowers the selected layer to the bottom of the map.
505            </para>
506    
507            </listitem>
508            <listitem>
509            <para>
510            The Visible tool
511            <inlinemediaobject>
512            <imageobject>
513            <imagedata fileref="../images/3_5_visible.png" format="PNG" scale="&imgscale;"/>
514            </imageobject>
515            <imageobject>
516            <imagedata fileref="./images/3_5_visible.eps" format="EPS" scale="&imgscale;"/>
517            </imageobject>
518            <textobject> <phrase>Visible</phrase> </textobject>
519            </inlinemediaobject> shows the selected layer in the map if it was
520            hidden.
521            </para>
522    
523            </listitem>
524            <listitem>
525            <para>
526            The Invisible tool
527            <inlinemediaobject>
528            <imageobject>
529            <imagedata fileref="../images/3_5_invisible.png" format="PNG" scale="&imgscale;"/>
530            </imageobject>
531            <imageobject>
532            <imagedata fileref="./images/3_5_invisible.eps" format="EPS" scale="&imgscale;"/>
533            </imageobject>
534            <textobject> <phrase>Invisible</phrase> </textobject>
535            </inlinemediaobject> hides the selected layer in the map.
536            </para>
537    
538            </listitem>
539            <listitem>
540            <para>
541            The Properties tool
542            <inlinemediaobject>
543            <imageobject>
544            <imagedata fileref="../images/3_5_props.png" format="PNG" scale="&imgscale;"/>
545            </imageobject>
546            <imageobject>
547            <imagedata fileref="./images/3_5_props.eps" format="EPS" scale="&imgscale;"/>
548            </imageobject>
549            <textobject> <phrase>Properties</phrase> </textobject>
550            </inlinemediaobject> opens the layer's properties dialog box.
551            Double-clicking on a layer or a group of a layer will open the
552            properties dialog for that layer.
553          </para>          </para>
554            </listitem>
555            </itemizedlist>
556            <para>
557            Along the bottom of the legend is the scalebar. The scalebar
558            will be available if there are any layers and the  map has a
559            projection set.
560            </para>
561            </section>
562    
563            <section><title>Exporting</title>
564            <para>
565            Under Windows, maps can be exported in Enhanced Metafile format
566            (<varname>.wmf</varname>)
567            from
568            <menuchoice>
569            <guimenu>Map</guimenu>
570            <guimenuitem>Export</guimenuitem>
571            </menuchoice> for use in reports, presentations, or further
572            modification. The current map view, legend, and, if available,
573            scalebar are exported. Under other platforms this option is not
574            available. Clicking this menu item open a file selection dialog
575            that lets the user select a location to export the map.
576            </para>
577          </section>          </section>
578    
579          <section><title>Printing</title>          <section><title>Printing</title>
580          <para>          <para>
581            The map can be printed using
582            <menuchoice>
583            <guimenu>Map</guimenu>
584            <guimenuitem>Print</guimenuitem>
585            </menuchoice>. The current map view, legend, and, if available,
586            scalebar are printed. A standard printing dialog will open allowing
587            the user to configure the printer. This dialog will differ depending
588            on which platform Thuban is running.
589          </para>          </para>
590          </section>          </section>
591    
592    </chapter>    </chapter>
593    
594    <chapter><title>Layer Management</title>    <chapter><title>Layer Management</title>
# Line 194  Line 597 
597    
598          <section><title>Types of Layers</title>          <section><title>Types of Layers</title>
599          <para>          <para>
600            There are two types of layers supported by Thuban: shape layers and
601            image layers. Shape layers consist of vector based shapes with
602            geo-referenced coordinates. There are three types of supported
603            shapes: polygons, lines (arc), and points. Image layers can be any image
604            file format supported by the Geo-spatial Data Abstraction Library
605            (GDAL). The images must have geographic
606            coordinate data either embedded within the file or in a separate
607            file that is in the same directory as the image file. GeoTIFF files
608            work very well with Thuban and were designed specifically to be image
609            layers in GIS programs.
610          </para>          </para>
611            <para>
612            All actions in the
613            <menuchoice>
614            <guimenu>Layer</guimenu>
615            </menuchoice> menu act on the currently selected layer in the legend.
616            </para>
617          </section>          </section>
618    
619          <section><title>Visibility</title>          <section><title>Properties</title>
620          <para>          <para>
621            To view the properties for a layer it must first be selected in the
622            legend. The menu option
623            <menuchoice>
624            <guimenu>Layer</guimenu>
625            <guimenuitem>Properties</guimenuitem>
626            </menuchoice> opens a dialog that displays a layer's properties.
627            All layers have a title which can be modified in the text field
628            provided. The type of layer is also shows. If the type is a type
629            of shape (polygon, arc, point) the classification table will be
630            shown. Image layers have no other properties other than title
631            and type.
632            </para>
633            <para>
634            <figure>
635            <title>Properties Window</title>
636            <mediaobject>
637            <imageobject><imagedata fileref="../images/4_2_layer_properties.png" format="PNG" scale="&imgscale;"/></imageobject>
638            <imageobject><imagedata fileref="./images/4_2_layer_properties.eps" format="EPS" scale="&imgscale;"/></imageobject>
639            </mediaobject>
640            </figure>
641            </para>
642            <para>
643            <figure>
644            <title>Properties Window</title>
645            <mediaobject>
646            <imageobject><imagedata fileref="../images/4_2_raster_layer_properties.png" format="PNG" scale="&imgscale;"/></imageobject>
647            <imageobject><imagedata fileref="./images/4_2_raster_layer_properties.eps" format="EPS" scale="&imgscale;"/></imageobject>
648            </mediaobject>
649            </figure>
650          </para>          </para>
651          </section>          </section>
652    
653          <section><title>Sequence</title>          <section><title>Visibility</title>
654          <para>          <para>
655            Sometimes it is not desirable to view all layers at the same time.
656            Some layers may take a long time to draw and so while navigating
657            around the map the user may not want to wait for the map to redraw
658            all the layers each time the map is changed. Each layer can be
659            independently turned on or off using the
660            <menuchoice>
661            <guimenu>Layer</guimenu>
662            <guimenuitem>Show</guimenuitem>
663            </menuchoice>
664            or
665            <menuchoice>
666            <guimenu>Layer</guimenu>
667            <guimenuitem>Hide</guimenuitem>
668            </menuchoice> options respectively.
669          </para>          </para>
670          </section>          </section>
671    
672          <section><title>Duplication</title>          <section><title>Duplication</title>
673          <para>          <para>
674            Layers and all their properties, including classifications, can
675            be duplicated using
676            <menuchoice>
677            <guimenu>Layer</guimenu>
678            <guimenuitem>Duplicate</guimenuitem>
679            </menuchoice>. Duplicating a layer is useful if the user wishes
680            to model a layer in several different ways. Even though the layers
681            overlap, by carefully selecting the shape properties it is possible
682            to display several pieces of information at once. For example, one
683            copy of a roads layer may be classified on a length property and
684            another copy may be classified on a type property. If the length
685            property was expressed with color and the type property expressed
686            with line thickness then it would be possible to view both
687            classifications by placing the type property copy over the
688            length property copy.
689          </para>          </para>
690          </section>          </section>
691    
         <section><title>Properties</title>  
         <para>  
         </para>  
         </section>  
692    </chapter>    </chapter>
693    
694    <chapter><title>Layer Classifications</title>    <chapter><title>Layer Classifications</title>
695      <para>      <para>
696        A layer classification is a way of assigning drawing properties to
697        groups of shapes based on attributes stored in the layer's table.
698        Only layer's with shapes can have a classification; image layers
699        cannot be classified.
700        </para>
701        <para>
702        A classification consists of a number of groups, each group
703        having a value or range of values to match against, and symbol
704        properties which control how a shape is drawn on the map. The user
705        selects which field in the table is used by the classification and
706        when the map is drawn the value for that field for each shape is
707        compared with each group's value. The properties of the first group
708        to match are used to draw the shape. This allows the user to get a
709        visual impression of not only how the data is laid out but also what
710        kind of data lies where.
711        </para>
712        <para>
713        A layer always has a classification. When a new layer is added to the
714        map, a default classification is created with the DEFAULT group. This
715        group cannot be removed but can be hidden (see below). Every shape in the
716        layer, regardless of its attributes, will match this group if no other
717        group matches.
718      </para>      </para>
719    
720          <section><title>Adding and Removing Classes</title>          <section><title>Editing Classifications</title>
721          <para>          <para>
722            A layer's classification can be modified under the properties dialog
723            (<menuchoice>
724            <guimenu>Layer</guimenu>
725            <guimenuitem>Properties</guimenuitem>
726            </menuchoice>). The layer's classification field can be set to None,
727            which simply assigns a DEFAULT group to the classification. No new
728            groups can be added to the classification if the field is None.
729            The user must first select a field to classify on. New groups can
730            be added to the classification with the <guibutton>Add</guibutton>
731            button.
732            </para>
733            <para>
734            To apply the changes to the map the user can click
735            either <guibutton>Try</guibutton> or <guibutton>OK</guibutton>.
736            <guibutton>Try</guibutton> will not close the dialog box, allowing
737            the user to see how the classification changes the map.
738            <guibutton>Revert</guibutton> will undo the last classification applied
739            to the map. <guibutton>OK</guibutton> will commit the changes and
740            close the dialog. The user will be unable to undo the changes.
741            <guibutton>Close</guibutton> simply closes the dialog box. If any
742            changes have not been applied with <guibutton>Try</guibutton> the
743            changes will not be applied to the map.
744            </para>
745            <para>
746            <figure>
747            <title>Properties Window</title>
748            <mediaobject>
749            <imageobject><imagedata fileref="../images/5_classification.png" format="PNG" scale="&imgscale;"/></imageobject>
750            <imageobject><imagedata fileref="./images/5_classification.eps" format="EPS" scale="&imgscale;"/></imageobject>
751            </mediaobject>
752            </figure>
753            </para>
754            <para>
755            The order of the groups in the classification is significant
756            except for the DEFAULT group, which remains at the top. When shapes
757            are matched against groups the matching begins at the first group
758            after the DEFAULT group so that groups higher in the list will
759            be checked first. Matching for a
760            given shape will stop at the first group that matches. The user can
761            use <guibutton>Move Up</guibutton> and <guibutton>Move Down</guibutton>
762            to change the order of the groups. The DEFAULT group will always
763            match a shape that hasn't matched another group.
764          </para>          </para>
765                <section><title>Visible</title>
766                <para>
767                The Visible column has check-boxes that determine whether a
768                classification group will be displayed in the legend. This is
769                useful if the user knows that the groups completely cover
770                the data set and don't want the DEFAULT group to be displayed
771                in the legend and on a printout.
772                </para>
773            </section>
774                <section><title>Symbols</title>
775                <para>
776                Each type of shape has its own type of symbol. Thuban supports three
777                types of shapes: polygons, lines, and points. Polygons and points
778                have outline and fill color, while lines have only line color. Each
779                group has associated symbol properties. To edit the symbol
780                properties for a group the user can double click on the Symbol
781                column or select a group and click the
782                <guibutton>Edit Symbol</guibutton> button.
783                </para>
784                </section>
785            <section><title>Value</title>
786                <para>
787                The Value column of the classification table is the value that will
788                be matched when the map is being drawn. The type of data that can
789                entered into this field depends on the type of data of the
790                classification field.
791                </para>
792                <para>
793                If the field is of type Text, anything entered
794                into the field is valid. The text will be compared literally to the
795                value of the shape attribute, including case sensitivity.
796                If the type is Integer, then any valid integer may be entered. In
797                addition, with special syntax, a range of values can be entered.
798                A range from <varname>start</varname> to <varname>end</varname>
799                inclusive is specified like this: <literal>[start;end]</literal>.
800                The exclusive range is specified like this:
801                <literal>]start;end[</literal>. Ranges can include infinity like
802                this: <literal>[-oo;oo]</literal>. Field types can also be of type
803                Decimal. They represent any rational number and can be used in
804                ranges as well.
805                </para>
806                </section>
807                <section><title>Label</title>
808                <para>
809                By default, the text that is displayed for a group in the legend
810                is the value for that group. The label can substitute a more
811                descriptive term in the legend.
812                </para>
813            </section>
814          </section>          </section>
815    
816          <section><title>Symbols</title>          <section><title>Generating Classes</title>
817          <para>          <para>
818            <figure>
819            <title>Generate Class</title>
820            <mediaobject>
821            <imageobject><imagedata fileref="../images/5_3_genclass.png" format="PNG" scale="&imgscale;"/></imageobject>
822            <imageobject><imagedata fileref="./images/5_3_genclass.eps" format="EPS" scale="&imgscale;"/></imageobject>
823            </mediaobject>
824            </figure>
825          </para>          </para>
         </section>  
   
         <section><title>Generating Classes</title>  
826          <para>          <para>
827            Creating a classification by hand can be tedious.
828            Thuban, therefore, provides a means of generating an entire
829            classification at once while still giving the user control over
830            how it appears. Clicking <guibutton>Generate Class</guibutton>
831            opens the <varname>Generate Classification</varname> dialog.
832            Under the <varname>Generate</varname> pull down there are at most
833            three different ways to generate classifications:
834            Unique Values, Uniform Distribution, and Quantiles. Some options
835            may not be available if the data type for the field does not
836            support them. For instance, <varname>Uniform Distribution</varname>
837            doesn't make sense for a Text field.
838          </para>          </para>
839            <para>
840            For every way of generating a classification, a color scheme must
841            be selected. Thuban provides several different color schemes that
842            affect how the group properties change over the classification.
843            It may be desirable that only certain properties change over the
844            classification. If the shape type is a polygon or a point then
845            the <guibutton>Fix Border Color</guibutton> option will be available.
846            This allows the user to select a border color for all classification
847            groups.
848            It is also possible to create a custom color scheme. Selecting
849            this option will display two symbols: the one of the left has the
850            properties of the first group and the one on the right has the
851            properties of the last group. Thuban will interpolate between these
852            two properties to generate the other groups.
853            <figure>
854            <title>Custom Color Scheme</title>
855            <mediaobject>
856            <imageobject><imagedata fileref="../images/5_2_custom_ramp.png" format="PNG" scale="&imgscale;"/></imageobject>
857            <imageobject><imagedata fileref="./images/5_2_custom_ramp.eps" format="EPS" scale="&imgscale;"/></imageobject>
858            </mediaobject>
859            </figure>
860            </para>
861            <para>
862            The Unique Values option lets the user select specific values that
863            appear in the table. Clicking <guibutton>Retrieve From Table</guibutton>
864            searches the table for all unique values and displays them in the
865            list on the left. Items can be selected and moved to the list on the
866            right. Each list can be sorted or reversed for easier searching.
867            The classification that is generated will be in the same order as
868            the list on the right.
869            <figure>
870            <title>Unique Values</title>
871            <mediaobject>
872            <imageobject><imagedata fileref="../images/5_2_unique_values.png" format="PNG" scale="&imgscale;"/></imageobject>
873            <imageobject><imagedata fileref="./images/5_2_unique_values.eps" format="EPS" scale="&imgscale;"/></imageobject>
874            </mediaobject>
875            </figure>
876            </para>
877            <para>
878            The Uniform Distribution option creates a user specified number of
879            groups of ranges such that each range covers equal intervals. The
880            minimum and maximum values can automatically be retrieved from the
881            table by clicking <guibutton>Retrieve From Table</guibutton>. The
882            stepping is how large each interval is. Adjusting this value will
883            automatically recalculate how many groups is appropriate.
884            <figure>
885            <title>Uniform Distribution</title>
886            <mediaobject>
887            <imageobject><imagedata fileref="../images/5_2_uniform_dist.png" format="PNG" scale="&imgscale;"/></imageobject>
888            <imageobject><imagedata fileref="./images/5_2_uniform_dist.eps" format="EPS" scale="&imgscale;"/></imageobject>
889            </mediaobject>
890            </figure>
891            </para>
892            <para>
893            The Quantiles option generates ranges based on the number of items
894            in the table. For example, by specifying five groups Thuban will
895            generate five groups with appropriate ranges such that 20% of the table
896            data is in each group. If it is impossible to generate exact
897            groupings, Thuban will issue a warning but allow the user to continue.
898            <figure>
899            <title>Quantiles</title>
900            <mediaobject>
901            <imageobject><imagedata fileref="../images/5_2_quantiles.png" format="PNG" scale="&imgscale;"/></imageobject>
902            <imageobject><imagedata fileref="./images/5_2_quantiles.eps" format="EPS" scale="&imgscale;"/></imageobject>
903            </mediaobject>
904            </figure>
905            </para>
906          </section>          </section>
907    </chapter>    </chapter>
908    
909    <chapter><title>Projection Management</title>    <chapter><title>Projection Management</title>
910      <para>      <para>
911        Projections control how the geographic data is displayed on the screen.
912        If multiple layers are loaded into Thuban where the geographic data
913        is in a different projection system, then the user must specify a
914        projection for each layer. The user must also tell Thuban which
915        projection the map is in. This can be the same as the layers or a different
916        projection in which case the layers are reprojected into that space.
917        The map projection can be set using
918        <menuchoice>
919        <guimenu>Map</guimenu>
920        <guimenuitem>Projection</guimenuitem>
921        </menuchoice> and the layer projection can be set using
922        <menuchoice>
923        <guimenu>Layer</guimenu>
924        <guimenuitem>Projection</guimenuitem>
925        </menuchoice>.
926        <figure>
927        <title>Projection Window</title>
928        <mediaobject>
929        <imageobject><imagedata fileref="../images/6_projection.png" format="PNG" scale="&imgscale;"/></imageobject>
930        <imageobject><imagedata fileref="./images/6_projection.eps" format="EPS" scale="&imgscale;"/></imageobject>
931        </mediaobject>
932        </figure>
933        </para>
934        <para>
935        Thuban is distributed with a sample collection of projections. The
936        user can create new projections and make them available to all
937        future Thuban sessions. They may also be exported and imported so
938        that custom projections can be distributed.
939      </para>      </para>
940            <section><title>Selecting a Projection</title>
941            <para>
942            The available projections are listed on the left. If the layer
943            or map already has a projection it will initially be highlighted
944            and will end with <varname>(current)</varname>. Selecting
945            <varname>&lt;None&gt;</varname> will cause Thuban to use the data as
946            it appears in the source file and will not use a projection.
947            </para>
948        </section>
949            <section><title>Editing a Projection</title>
950            <para>
951            Whenever a projection is selected from the list its properties
952            are displayed on the right. These properties can be changed
953            and the changes saved to the selected projection using
954            <guibutton>Update</guibutton>. Only a projection that comes
955            from a file can be updated, so if the current layer's projection
956            is selected, <guibutton>Update</guibutton> will be disabled.
957            <guibutton>Add to List</guibutton> adds the projection to the
958            list of available projections as a new entry, and thus makes it
959            available to future Thuban sessions. Clicking <guibutton>New</guibutton>
960            will create an entirely new, empty projection. The
961            <guibutton>Remove</guibutton> button will permanently remove a
962            projection from the list of available projections.
963            </para>
964            <para>
965            To apply the selected projection to the map the user can click
966            either <guibutton>Try</guibutton> or <guibutton>OK</guibutton>.
967            <guibutton>Try</guibutton> will not close the dialog box, allowing
968            the user to see how the projeciton changes the map.
969            <guibutton>Revert</guibutton> will undo the last projection applied
970            to the map. <guibutton>OK</guibutton> will commit the changes and
971            close the dialog. The user will be unable to undo the changes.
972            <guibutton>Close</guibutton> simply closes the dialog box. If no
973            selection has been applied with <guibutton>Try</guibutton> the
974            selection will not be applied to the map.
975            </para>
976        </section>
977            <section><title>Importing/Exporting Projections</title>
978            <para>
979            The projections that appear in the list of available projections
980            can be exported to another file that the user chooses. By selecting
981            one or more projections and clicking <guibutton>Export</guibutton>
982            the user will be able to select a file in which to store those
983            projections.
984            The file can then be distributed to other Thuban users. To import
985            a projection file the user can click <guibutton>Import</guibutton>.
986            The imported projections are added to the list and are then available
987            to the current session and any future Thuban sessions.
988            </para>
989        </section>
990    </chapter>    </chapter>
991    
992    <chapter><title>Table Management</title>    <chapter><title>Table Management</title>
993      <para>      <para>
994        Thuban distinguishes two different types of tables: Attribute tables
995        (which belong to a layer) and normal data tables. Both provide
996            the same general functionality with the difference that actions on an
997        attribute table might also effect the map display.
998      </para>      </para>
999    
1000        <section><title>Table View</title>
1001            <para>
1002            <figure>
1003            <title>Table View</title>
1004            <mediaobject>
1005            <imageobject><imagedata fileref="../images/7_1_table_view.png" format="PNG" scale="&imgscale;"/></imageobject>
1006            <imageobject><imagedata fileref="./images/7_1_table_view.eps" format="EPS" scale="&imgscale;"/></imageobject>
1007            </mediaobject>
1008            </figure>
1009            </para>
1010            <para>
1011            Thuban provides a standard dialog to display table contents, the
1012            Table View. The view has five sections: The title, selections,
1013            the table grid, export functions, and the status bar.
1014            </para>
1015            <para>
1016            The title bar identifies the table with its name.
1017            </para>
1018            <para>
1019            The selections box let the user perform simple analysis on the data
1020            based on comparisons: The first choice must be a field identifier of
1021            the table, the second choice determines the type of comparison. The
1022            third choice can be either a specific value (interpreted as numerical
1023            or string depending on the type of the first field) or a second field
1024            identifier. Thus you can perform analysis like selecting all
1025            records where <literal>population > 10000</literal> or
1026            <literal>cars_per_inhabitant < bikes_per_inhabitant</literal>
1027            (note that the field names are only explanatory, the dBase files
1028            allow only 11 character field names).
1029          
1030            Selections can be combined either by applying a selection only on
1031            a previously selected set of records or by adding the results of a
1032            selection to a previous set. The default is that a selection replaces
1033            earlier results.
1034            </para>
1035            <para>
1036            The table grid shows the contents of the table (one record per row),
1037            with highlighted selection results. Columns and rows can be resized.
1038            </para>
1039            <para>
1040            The contents of a table can be exported into a file, either dBase
1041            format (DBF) or comma separated values (CSV). The
1042            <guibutton>Export</guibutton> button
1043            raises a file dialog to specify a path and file name, the export type
1044            is determined by the file extension (either .dbf or .csv).
1045    
1046            The <guibutton>Export Selection</guibutton> button works similarly
1047            but exports only the selected records.
1048    
1049            The <guibutton>Close</guibutton> button closes the table view window.
1050            This is different from the menu item
1051            <menuchoice>
1052            <guimenu>Table</guimenu>
1053            <guimenuitem>Close</guimenuitem>
1054            </menuchoice> which unloads the table from Thuban.
1055            </para>
1056            <para>
1057            The status bar displays some statistics about the table and optional
1058            selection results.
1059            </para>
1060        </section>
1061    
1062        <section><title>General Functionality (Menu Table)</title>
1063            <para>
1064            The general functions affect all tables open in Thuban. Attribute
1065            tables are considered here as normal data tables (with the exception
1066            that they cannot be closed).
1067            </para>
1068            <section><title>Open</title>
1069                <para>
1070                The
1071                <menuchoice>
1072                <guimenu>Table</guimenu>
1073                <guimenuitem>Open</guimenuitem>
1074                </menuchoice>
1075                item raises a file dialog to let you select a
1076                dBase file from the file system to be loaded into Thuban read-only.
1077                On <guibutton>OK</guibutton> the selected file is loaded and a
1078                table view is opened.
1079                </para>
1080            </section>
1081    
1082            <section><title>Close</title>
1083                <para>
1084                The
1085                <menuchoice>
1086                <guimenu>Table</guimenu>
1087                <guimenuitem>Close</guimenuitem>
1088                </menuchoice>
1089                item raises a dialog listing the currently open
1090                data tables
1091                (loaded via
1092                <menuchoice>
1093                <guimenu>Table</guimenu>
1094                <guimenuitem>Open</guimenuitem>
1095                </menuchoice>). Selected tables are dereferenced on confirmation.
1096                Since tables are opened read-only the contents of the tables are
1097                not affected.
1098    
1099                Any open views of the tables are closed as well.
1100    
1101                Tables used in a join cannot be closed.
1102                </para>
1103            </section>
1104    
1105            <section><title>Rename</title>
1106                <para>
1107                <menuchoice>
1108                <guimenu>Table</guimenu>
1109                <guimenuitem>Rename</guimenuitem>
1110                </menuchoice> changes the table title.
1111                </para>
1112            </section>
1113    
1114            <section><title>Show</title>
1115                <para>
1116                The
1117                <menuchoice>
1118                <guimenu>Table</guimenu>
1119                <guimenuitem>Show</guimenuitem>
1120                </menuchoice>
1121                item raises a list of available tables (explicitly
1122                loaded, attribute tables, results of a join). Selected tables are
1123                show in tables views on <guibutton>OK</guibutton>.
1124                </para>
1125            </section>
1126    
1127            <section><title>Join</title>
1128                <para>
1129                <figure>
1130                <title>Join Tables</title>
1131                <mediaobject>
1132                <imageobject><imagedata fileref="../images/7_2_5_join.png" format="PNG" scale="&imgscale;"/></imageobject>
1133                <imageobject><imagedata fileref="./images/7_2_5_join.eps" format="EPS" scale="&imgscale;"/></imageobject>
1134                </mediaobject>
1135                </figure>
1136                </para>
1137                <para>
1138                The
1139                <menuchoice>
1140                <guimenu>Table</guimenu>
1141                <guimenuitem>Join</guimenuitem>
1142                </menuchoice>
1143                item raises a dialog to specify the two tables to be
1144                joined. The join results in a new table named 'Join of "left table"
1145                and "right table"'.
1146    
1147                The dialog lets you select the two tables to be joined and the two
1148                fields the join has to be performed on. By default, the new
1149                table contains only those records which are matched by the join.
1150    
1151                If you want to preserve the records of the left table you can
1152                perform an outer join. The fields from the right table for records
1153                not matched by the join are filled with <varname>None</varname> in
1154                this case.
1155                </para>
1156            </section>
1157    
1158        </section>
1159        <section><title>Attribute Tables</title>
1160            <para>
1161                To clearly separate between both types of tables (data and
1162            attribute), Thuban provides functionality regarding the attribute
1163            tables under the <menuchoice><guimenu>Layer</guimenu></menuchoice> menu.
1164            </para>
1165    
1166            <section><title>Show Table</title>
1167                <para>
1168                <menuchoice>
1169                <guimenu>Layer</guimenu>
1170                <guimenuitem>Show Table</guimenuitem>
1171                </menuchoice>
1172                opens the attribute table of the currently active layer in a table
1173                view.
1174    
1175                In addition to the functionality described above selections
1176                affect also the map display: objects related to selected records
1177                are highlighted.
1178                </para>
1179            </section>
1180    
1181            <section><title>Join Table</title>
1182                <para>
1183                Unlike the join described above, the join does not result in a
1184                new table. The attribute table of the currently active layer is the
1185                left table and other tables are joined to this table. The results of
1186                the join are available for classification.
1187    
1188                As a consequence, the join cannot result in fewer
1189                records than the source attribute table. The user is warned if the
1190                right table does not fulfill this constraint. An outer join must be
1191                used in such cases.
1192                </para>
1193            </section>
1194    
1195            <section><title>Unjoin Table</title>
1196                <para>
1197                As said above, a normal table cannot be closed while it is still
1198                used in a join. While the joined table resulting from a join of
1199                normal tables can be simply closed (and thereby dereferencing
1200                the source tables), this is not possible for attribute tables.
1201    
1202                Hence joins on attribute tables must be solved explicitly. This is
1203                what the
1204                <menuchoice>
1205                <guimenu>Layer</guimenu>
1206                <guimenuitem>Unjoin Table</guimenuitem>
1207                </menuchoice>
1208                item is used for: The last join for the currently
1209                active layer is solved.
1210                </para>
1211            </section>
1212        </section>
1213    </chapter>    </chapter>
1214    
1215    <chapter><title>Trouble Shooting</title>    <chapter><title>Trouble Shooting</title>
1216      <para>      <para>
1217        Here are a few problems that users have encountered when first using Thuban.
1218        </para>
1219        <para>
1220    
1221        <itemizedlist>
1222        <listitem>
1223        <para>After adding two or more layers nothing is drawn in the map window.
1224        </para>
1225        <para>
1226        This is probably because the layers have different projections. Projections
1227        must be set on all layers and on the map itself if the layers' projections
1228        are different.
1229        </para>
1230        </listitem>
1231    
1232        <listitem>
1233        <para>Thuban crashes on startup with the error
1234            <literal>NameError: global name 'False' is not defined</literal>.
1235        </para>
1236        <para>
1237        <varname>True</varname> and <varname>False</varname> were only introduced
1238        in Python 2.2.1. Thuban depends on at least Python 2.2.1.
1239      </para>      </para>
1240        </listitem>
1241    
1242        <listitem>
1243        <para>After compiling Thuban, Thuban crashes with an error similar to
1244            <literal>
1245            ImportError: /usr/local//lib/thuban/Thuban/../Lib/wxproj.so: undefined symbol: __gxx_personality_v0
1246            </literal>
1247        </para>
1248        <para>
1249        Thuban depends on the wxWindows library. If Thuban is compiled with an
1250        incompatible version of the compiler than wxWindows was compiled with
1251        this error may occur. Try compiling with a different version of the
1252        compiler.
1253        </para>
1254        </listitem>
1255        </itemizedlist>
1256        </para>
1257        <para>
1258        If an error occurs Thuban will display a dialog indicating the error
1259        before closing. The text should be copied and reported to the
1260        <ulink url="http://thuban.intevation.org/bugtracker.html">
1261        Intevation bugtracker
1262        </ulink>.
1263        More information about the system is available from
1264        <menuchoice><guimenu>Help</guimenu><guimenuitem>About</guimenuitem></menuchoice> box.
1265        This should also be included in the bug report.
1266        <figure>
1267        <title>Error Dialog</title>
1268        <mediaobject>
1269        <imageobject><imagedata fileref="../images/8_int_error.png" format="PNG" scale="&imgscale;"/></imageobject>
1270        <imageobject><imagedata fileref="./images/8_int_error.eps" format="EPS" scale="&imgscale;"/></imageobject>
1271        </mediaobject>
1272        </figure>
1273        </para>
1274    
1275    </chapter>    </chapter>
1276    
1277    <appendix><title>Supported Data Sources</title>    <appendix><title>Supported Data Sources</title>
1278      <para>      <para>
1279      </para>      </para>
1280        <variablelist>
1281        <varlistentry>
1282        <term>Shapefile</term>
1283        <listitem>
1284            <para>
1285            The Shapefile format has become a standard format for saving
1286            geographic vector information. It supports polygons, lines, and
1287            points.
1288            
1289            <ulink url="http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf">
1290            Technical Specification.
1291            </ulink>  
1292            </para>
1293        </listitem>
1294        </varlistentry>
1295    
1296        <varlistentry>
1297        <term>dBase file</term>
1298        <listitem>
1299            <para>
1300            dBase files are used to store the attributes for each layer. This
1301            is closely associated with the Shapefile format. For detailed
1302            specifications on the correct format of a dBase file used with
1303            Thuban please see the Technical Specification for the Shapefile
1304            format above.
1305            </para>
1306        </listitem>
1307        </varlistentry>
1308    
1309        <varlistentry>
1310        <term>Raster files</term>
1311        <listitem>
1312            <para>
1313            Binding the GDAL library Thuban supports numerous raster file formats,
1314            see <ulink url="http://www.remotesensing.org/gdal/formats_list.html">
1315            GDAL format list</ulink> for details.</para>
1316    
1317            <para>Most commonly used is the <emphasis>TIFF/GeoTIFF</emphasis>
1318            format: Raster maps are provided as TIFF images, with an additional
1319            "world file" storing the geographic reference (usually with an
1320            extension ".tfw").
1321            </para>
1322        </listitem>
1323        </varlistentry>
1324    
1325        </variablelist>
1326    </appendix>    </appendix>
1327    
1328    <appendix><title>Supported Projections</title>    <appendix><title>Supported Projections</title>
1329      <para>      <para>
1330        The following types of projections are directly support by
1331        Thuban. The specific values for each are provided by the user
1332        to create custom projections. Thuban comes with predefined
1333        projections which are available through the Projections dialog.
1334        </para>
1335        <itemizedlist>
1336        <listitem>
1337            <para>Geographic</para>
1338            <itemizedlist>
1339            <listitem><para><literal>Ellipsoid</literal></para></listitem>
1340            <listitem><para>
1341                    <literal>Source Data</literal>: either Degrees or Radians
1342                    </para></listitem>
1343            </itemizedlist>
1344        </listitem>
1345        <listitem>
1346            <para>Lambert Conic Conformal</para>
1347        <itemizedlist>
1348            <listitem><para><literal>Ellipsoid</literal></para></listitem>
1349            <listitem><para><literal>Latitude of 1st standard parallel</literal></para></listitem>
1350            <listitem><para><literal>Latitude of 2nd standard parallel</literal></para></listitem>
1351            <listitem><para><literal>Central Meridian</literal></para></listitem>
1352            <listitem><para><literal>Latitude of Origin</literal></para></listitem>
1353            <listitem><para><literal>False Easting</literal> (meters)</para></listitem>
1354            <listitem><para><literal>False Northing</literal> (meters)</para></listitem>
1355        </itemizedlist>
1356        </listitem>
1357        <listitem>
1358            <para>Transverse Mercator</para>
1359        <itemizedlist>
1360            <listitem><para><literal>Ellipsoid</literal></para></listitem>
1361            <listitem><para><literal>Latitude</literal>of origin</para></listitem>
1362            <listitem><para><literal>Longitude</literal>at central meridian</para></listitem>
1363            <listitem><para><literal>Scale Factor</literal>at central meridian</para></listitem>
1364            <listitem><para><literal>False Easting</literal> (meters)</para></listitem>
1365            <listitem><para><literal>False Northing</literal> (meters)</para></listitem>
1366        </itemizedlist>
1367        </listitem>
1368        <listitem>
1369            <para>Universal Transverse Mercator</para>
1370        <itemizedlist>
1371            <listitem><para><literal>Ellipsoid</literal></para></listitem>
1372            <listitem><para><literal>Zone</literal>
1373                    (can be guessed appling the Propose button)</para></listitem>
1374            <listitem><para><literal>Southern Hemisphere</literal> flag</para></listitem>
1375        </itemizedlist>
1376        </listitem>
1377        </itemizedlist>
1378        
1379        <para>
1380        Thuban comes with a sample set of map projections for various
1381        European countries. Apart from the basic projection they differ
1382        especially in their parameterization:
1383        </para>
1384        <itemizedlist>
1385        <listitem><para>Belgium Datum 1972 (Lambert Conic Conformal)</para>
1386        </listitem>
1387    
1388        <listitem><para>Gauss-Boaga Zone 1 (Italy, Transverse Mercartor)</para>
1389        </listitem>
1390    
1391        <listitem><para>Gauss-Krueger Zone 2 (Germany, Transverse Mercartor)
1392        </para>
1393        </listitem>
1394    
1395        <listitem><para>Reseau Geodesique Francaise
1396        (France, Lambert Conic Conformal)</para>
1397        </listitem>
1398    
1399        <listitem><para>UK National Grid (United Kingdom, Transverse Mercartor)
1400        </para>
1401        </listitem>
1402        </itemizedlist>
1403    
1404        <para>
1405        Thuban uses the comprehensive PROJ library for projections. PROJ provides
1406        more than the four commonly used projections described above. If needed
1407        Thuban can be easily extended to a new projection covered by PROJ.
1408      </para>      </para>
1409    </appendix>    </appendix>
1410    
1411  </book>  </book>
1412    
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