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<?xml version="1.0" encoding="ISO-8859-1"?> |
<?xml version="1.0" encoding="ISO-8859-1"?> |
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<!DOCTYPE book |
<!DOCTYPE book |
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PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" |
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<!-- $ Revision: $ --> |
[<!ENTITY imgscale "70">]> |
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|
<!-- $Revision$ --> |
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<book> |
<book> |
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<bookinfo> |
<bookinfo> |
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<title>Thuban Manual</title> |
<title>Thuban Manual</title> |
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<author> |
<author> |
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<firstname></firstname><surname></surname> |
<firstname>Jonathan</firstname><surname>Coles</surname> |
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</author> |
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<author> |
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<firstname>Jan-Oliver</firstname><surname>Wagner</surname> |
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</author> |
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<author> |
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<firstname>Frank</firstname><surname>Koormann</surname> |
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</author> |
</author> |
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<copyright> |
<copyright> |
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<year>2003</year> |
<year>2003</year> |
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|
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<chapter><title>Introduction</title> |
<chapter><title>Introduction</title> |
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<para> |
<para> |
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Thuban is an interactive geographic data viewer. |
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It has been developed because there was no simple interactive |
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viewer for geographic information available as Free Software. Thuban is |
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written in Python and C++ and uses the wxWindows library allowing it to |
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run on many different platforms, including GNU/Linux and Windows. |
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</para> |
</para> |
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<para> |
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Geographic data viewers are a necessary tool as they allow one to |
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get a visual |
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impression of the positional relationship of the information that may not |
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be apparent from simple inspection of the data values themselves. |
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Thuban allows the user to create a session that displays |
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geographic data and then explore that data through navigation and |
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manipulation of how it is drawn. The results can then be saved or printed. |
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</para> |
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<para> |
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Thuban arranges a session in a hierarchy. A session contains a map which |
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consists of layers. Each layer represents one kind of data set. For |
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instance, there may be a layer for roads and another layer for buildings. |
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These layers can either be vector shapes or images. |
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</para> |
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|
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<section><title>Installation</title> |
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<para> |
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Thuban is actively supported under Debian Testing (sarge), RedHat 7.2, |
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and Windows 2000. Thuban depends on the following packages. These |
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packages can also be found on the |
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<ulink url="http://thuban.intevation.org/download.html"> |
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Thuban Download site |
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</ulink>. |
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<itemizedlist> |
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<listitem><para>Python 2.2.1 (<literal>http://www.python.org</literal>)</para></listitem> |
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<listitem><para>wxWindows 2.4 (<literal>http://www.wxwindows.org</literal>)</para></listitem> |
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<listitem><para>wxPython 2.4 (<literal>http://www.wxpython.org</literal>)</para></listitem> |
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<listitem><para>proj 4.4.5 Projection Library (<literal>http://www.remotesensing.org/proj/</literal>)</para></listitem> |
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<listitem><para>GDAL 1.1.8 (<literal>http://www.remotesensing.org/gdal/</literal>)</para></listitem> |
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<listitem><para>SQLite 2.8.3 (<literal>http://www.hwaci.com/sw/sqlite/</literal>)</para></listitem> |
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<listitem><para>PySQLite 0.4.3 (<literal>http://pysqlite.sourceforge.net</literal>)</para></listitem> |
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</itemizedlist> |
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</para> |
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<para> |
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Along with the source codes, the download page also offers |
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full installation packages for Debian, Windows and RPM-based systems |
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(Mandrake, RedHat, SuSE, etc). |
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</para> |
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</section> |
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|
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<section><title>The Main Window</title> |
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<para> |
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<figure> |
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<title>The Main Window</title> |
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<mediaobject> |
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<imageobject> <imagedata fileref="../images/1_2_mainwindow.png" format="PNG" scale="&imgscale;"/> </imageobject> |
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<imageobject> <imagedata fileref="./images/1_2_mainwindow.ps" format="EPS" scale="&imgscale;"/> </imageobject> |
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</mediaobject> |
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</figure> |
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</para> |
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|
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<para> |
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The map window shows the current state of the map and is where |
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the user can interact with the map using the tools. |
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</para> |
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|
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<para> |
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The legend on the left displays a list of the current layers and |
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any visible classification groups. In the example, each shape layer |
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has a default classification which specifies how the shapes in each |
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layer are drawn. Layers that are higher in the list appear |
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``closer'' to the user. The legend can be closed by clicking on the |
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small X in the upper right-hand region of the legend. |
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To open it again, use |
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<menuchoice> |
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<guimenu>Map</guimenu> |
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<guimenuitem>Legend</guimenuitem> |
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</menuchoice>. |
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The legend is also dockable, which means that it can be detached |
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from the main window by clicking on the small button next to the |
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close button. It can be attached by clicking the same button |
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again. |
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</para> |
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<para> |
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The status bar displays different information depending on the |
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current context. If the user is selecting an item from the menu |
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then the status bar will display a short help message indicating |
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what each menu item is for. If the user has a tool selected then |
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the position of the cursor on the map is displayed. |
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</para> |
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<para> |
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The tool bar provides quick access to the commonly needed tools. |
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By hovering over each button the user can see a short messages |
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describing what the tool does. The tools provided are Zoom In, Zoom |
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Out, Pan, Full Extent, Full Layer Extent, Full Shape Extent, Identify, |
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and Label. Each of the tools will be explained in further detail later |
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in the manual. |
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</para> |
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</section> |
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|
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</chapter> |
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|
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<chapter><title>Session Management</title> |
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|
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<section><title>Starting a New Session</title> |
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<para> |
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A new session can be started from |
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<menuchoice> |
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<guimenu>File</guimenu> |
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<guimenuitem>New Session</guimenuitem> |
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</menuchoice>. |
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If a session is already loaded and has been modified without |
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being saved a prompt will ask if the current session should |
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be saved. A new session consists of an empty map with no |
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layers and no tables. |
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</para> |
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</section> |
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|
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<section><title>Opening a Session</title> |
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<para> |
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A session can be opened from |
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<menuchoice> |
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<guimenu>File</guimenu> |
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<guimenuitem>Open Session</guimenuitem> |
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</menuchoice>. A dialog box will open allowing the user to browse |
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for a Thuban Session file. Thuban session files end with |
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<varname>.thuban</varname>. Selecting a file a clicking |
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<guibutton>OK</guibutton> will load the session into Thuban. |
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|
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If a session is already loaded and has been modified without |
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being saved a prompt will ask if the current session should |
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be saved. |
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</para> |
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</section> |
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|
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<section><title>Saving a Session</title> |
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<para> |
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A session can be saved from |
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<menuchoice> |
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<guimenu>File</guimenu> |
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<guimenuitem>Save Session</guimenuitem> |
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</menuchoice>. A dialog box will open allowing the user to browse |
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the file system and select a place to save the session. Thuban |
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sessions should be saved under a name ending in |
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<varname>.thuban</varname>. If the file already exists the user |
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will be prompted to save under a different name or overwrite the |
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existing file. |
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</para> |
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</section> |
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|
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<section><title>The Session Info-Tree</title> |
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<para> |
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<figure> |
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<title>Session Info Tree</title> |
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<mediaobject> |
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<imageobject><imagedata fileref="../images/2_4_session_tree.png" format="PNG" scale="&imgscale;"/></imageobject> |
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<imageobject><imagedata fileref="./images/2_4_session_tree.eps" format="EPS" scale="&imgscale;"/></imageobject> |
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</mediaobject> |
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</figure> |
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</para> |
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<para> |
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The session info-tree is primarily intended for developers working |
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with Thuban. It displays many of the internal values for the session, |
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map, and layers. It can be opened from |
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<menuchoice> |
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<guimenu>File</guimenu> |
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<guimenuitem>Session Tree</guimenuitem> |
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</menuchoice>. |
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</para> |
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</section> |
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</chapter> |
</chapter> |
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|
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<chapter><title>Map Management</title> |
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<para> |
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The map consists of a number of layers where each layer represents a |
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different type of data set. By interacting with the map the user can |
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visually explore the data. |
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</para> |
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<para> |
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The map can have a name that will appear in the Thuban title bar. |
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The map name can be changed using |
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<menuchoice> |
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<guimenu>Map</guimenu> |
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<guimenuitem>Rename</guimenuitem> |
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</menuchoice>. |
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</para> |
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<para> |
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<inlinemediaobject> |
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<imageobject> |
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<imagedata fileref="../images/3_rename_map.png" format="PNG" scale="&imgscale;"/> |
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</imageobject> |
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<imageobject> |
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<imagedata fileref="./images/3_rename_map.eps" format="EPS" scale="&imgscale;"/> |
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</imageobject> |
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<textobject> <phrase>Rename Map</phrase> </textobject> |
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</inlinemediaobject> |
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</para> |
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|
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<section><title>Adding and Removing Layers</title> |
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<para> |
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There are two types of layers that can be added to a map: shape layers |
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and image layers. Shape layers are stored in Shapefile format, a |
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standard file format for storing geographic objects. These |
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files have the extension ``.shp''. Associated with |
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the shape file is a database file which stores attributes for |
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each shape in the shape file. This file, in dBase format, |
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has the extension ``.dbf''. Both files must have the same base name. |
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For example, if there is a shape file named roads.shp there must |
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also be a file roads.dbf. |
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</para> |
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<para> |
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Shape layers can be added to the map with |
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<menuchoice> |
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<guimenu>Map</guimenu> |
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<guimenuitem>Add Layer</guimenuitem> |
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</menuchoice>. |
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Thuban will load all files with the same base name, so it doesn't |
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matter if the shape file or database file is selected. |
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</para> |
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|
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<para> |
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Image layers can be added to the map with |
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<menuchoice> |
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<guimenu>Map</guimenu> |
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<guimenuitem>Add Image Layer</guimenuitem> |
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</menuchoice>. |
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It is important to select a valid image file that has geographic |
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data associated with it. The data can be embedded in the file itself, |
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or in another file. If geographic information cannot be found, Thuban |
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will report an error. |
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</para> |
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</section> |
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|
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<section><title>Navigation</title> |
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<para> |
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The map can be explored by using the navigation tools available on |
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the tool bar or from the |
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<menuchoice><guimenu>Map</guimenu></menuchoice> menu. |
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</para> |
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<itemizedlist> |
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<listitem> |
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<para> |
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The ZoomIn tool |
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<inlinemediaobject> |
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<imageobject> |
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<imagedata fileref="../images/3_2_zoomin.png" format="PNG" scale="&imgscale;"/> |
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</imageobject> |
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<imageobject> |
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<imagedata fileref="./images/3_2_zoomin.eps" format="EPS" scale="&imgscale;"/> |
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</imageobject> |
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<textobject> <phrase>ZoomIn Tool</phrase> </textobject> |
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</inlinemediaobject> |
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enlarges a region of the map. Clicking once on the map |
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will double the magnification and center the map on the point that |
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was clicked. Clicking and dragging selects a region that will be |
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enlarged to fit the window. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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The ZoomOut tool |
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<inlinemediaobject> |
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<imageobject> |
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<imagedata fileref="../images/3_2_zoomout.png" format="PNG" scale="&imgscale;"/> |
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</imageobject> |
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<imageobject> |
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<imagedata fileref="./images/3_2_zoomout.eps" format="EPS" scale="&imgscale;"/> |
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</imageobject> |
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<textobject> <phrase>ZoomOut Tool</phrase> </textobject> |
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</inlinemediaobject> |
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shrinks the map so that a larger region is visible. A single click |
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reduces the magnification by a factor of two. Clicking and dragging |
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selects a box such that the current contents of the window will be |
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scaled to fit into that box. |
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</para> |
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</listitem> |
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|
<listitem> |
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|
<para> |
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|
The Pan tool |
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<inlinemediaobject> |
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<imageobject> |
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<imagedata fileref="../images/3_2_pan.png" format="PNG" scale="&imgscale;"/> |
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</imageobject> |
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<imageobject> |
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<imagedata fileref="./images/3_2_pan.eps" format="EPS" scale="&imgscale;"/> |
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</imageobject> |
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<textobject> <phrase>Pan Tool</phrase> </textobject> |
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</inlinemediaobject> |
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allows the user to move the map around by clicking and dragging. |
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</para> |
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|
</listitem> |
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|
<listitem> |
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|
<para> |
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|
The Full Extent tool |
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|
<inlinemediaobject> |
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<imageobject> |
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<imagedata fileref="../images/3_2_fullextent.png" format="PNG" scale="&imgscale;"/> |
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</imageobject> |
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<imageobject> |
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<imagedata fileref="./images/3_2_fullextent.eps" format="EPS" scale="&imgscale;"/> |
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</imageobject> |
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<textobject> <phrase>Full Extent Tool</phrase> </textobject> |
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</inlinemediaobject> |
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rescales the viewable region so that the entire map is visible. |
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</para> |
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|
</listitem> |
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|
<listitem> |
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|
<para> |
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|
The Full Layer Extent tool |
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|
<inlinemediaobject> |
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|
<imageobject> |
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<imagedata fileref="../images/3_2_fulllayerextent.png" format="PNG" scale="&imgscale;"/> |
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</imageobject> |
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<imageobject> |
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<imagedata fileref="./images/3_2_fulllayerextent.eps" format="EPS" scale="&imgscale;"/> |
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</imageobject> |
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<textobject> <phrase>Full Layer Extent Tool</phrase> </textobject> |
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</inlinemediaobject> |
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rescales the viewable region so that the currently selected |
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|
layer fits within the window. If no layer is selected this button |
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will be disabled. |
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|
</para> |
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|
</listitem> |
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|
<listitem> |
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|
<para> |
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|
The Full Shape Extent tool |
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<inlinemediaobject> |
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<imageobject> |
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<imagedata fileref="../images/3_2_fullshapeextent.png" format="PNG" scale="&imgscale;"/> |
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</imageobject> |
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|
<imageobject> |
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<imagedata fileref="./images/3_2_fullshapeextent.eps" format="EPS" scale="&imgscale;"/> |
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</imageobject> |
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|
<textobject> <phrase>Full Shape Extent Tool</phrase> </textobject> |
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</inlinemediaobject> |
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rescales the viewable region so that the currently selected |
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shape fits within the window. If the shape is a point, it is |
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centered and the map is zoomed all the way in. If no shape is |
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selected this button will be disabled. This feature is especially |
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helpful when identifying an object related to a selected record |
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in a tableview (see below). |
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|
|
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|
</para> |
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|
</listitem> |
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|
</itemizedlist> |
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|
</section> |
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|
|
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<section><title>Object Identification</title> |
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|
<para> |
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|
Objects on the map can be identified using the Identify tool |
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|
<inlinemediaobject> |
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|
<imageobject> |
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<imagedata fileref="../images/3_3_identify.png" format="PNG" scale="&imgscale;"/> |
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</imageobject> |
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|
<imageobject> |
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<imagedata fileref="./images/3_3_identify.eps" format="EPS" scale="&imgscale;"/> |
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</imageobject> |
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<textobject> <phrase>Identify Tool</phrase> </textobject> |
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</inlinemediaobject>. |
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Clicking on an object selects that object and opens a dialog which |
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shows all the table attributes for that object. Any current selection |
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is lost. Objects on the map are typically shapes and this document |
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will often refer to objects as shapes. |
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</para> |
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|
</section> |
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|
|
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|
<section><title>Object Labeling</title> |
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|
<para> |
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|
Objects can be labeled using the Label tool |
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|
<inlinemediaobject> |
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|
<imageobject> |
| 395 |
|
<imagedata fileref="../images/3_3_label.png" format="PNG" scale="&imgscale;"/> |
| 396 |
|
</imageobject> |
| 397 |
|
<imageobject> |
| 398 |
|
<imagedata fileref="./images/3_3_label.eps" format="EPS" scale="&imgscale;"/> |
| 399 |
|
</imageobject> |
| 400 |
|
<textobject> <phrase>Label Tool</phrase> </textobject> |
| 401 |
|
</inlinemediaobject>. |
| 402 |
|
Clicking on an object selects that object and opens a dialog which |
| 403 |
|
displays the table attributes for that object. An attribute can |
| 404 |
|
be selected to be the label on the map. The label will be placed |
| 405 |
|
at the center of the shape. Clicking on an object that already has |
| 406 |
|
a label will remove the label. |
| 407 |
|
</para> |
| 408 |
|
</section> |
| 409 |
|
|
| 410 |
|
<section><title>The Legend</title> |
| 411 |
|
<para> |
| 412 |
|
<inlinemediaobject> |
| 413 |
|
<imageobject> |
| 414 |
|
<imagedata fileref="../images/3_5_legend.png" format="PNG" scale="&imgscale;"/> |
| 415 |
|
</imageobject> |
| 416 |
|
<imageobject> |
| 417 |
|
<imagedata fileref="./images/3_5_legend.eps" format="EPS" scale="&imgscale;"/> |
| 418 |
|
</imageobject> |
| 419 |
|
<textobject> <phrase>Legend</phrase> </textobject> |
| 420 |
|
</inlinemediaobject> |
| 421 |
|
</para> |
| 422 |
|
<para> |
| 423 |
|
The Legend provides an overview of the layers in the map. Layers |
| 424 |
|
that appear higher in the legend will appear ``closer'' to the user. |
| 425 |
|
If a layer supports classification (currently, only shape layers |
| 426 |
|
have this feature) then the classification groups will be shown |
| 427 |
|
below each layer. The properties for each group are also displayed |
| 428 |
|
with a small graphic. Polygon layers appear as rectangles, lines |
| 429 |
|
appear as curved lines, and points appear as circles. |
| 430 |
|
</para> |
| 431 |
|
<para> |
| 432 |
|
Along the top of the legend is a toolbar which allows quick access |
| 433 |
|
to some of the layer manipulation options under |
| 434 |
|
<menuchoice><guimenu>Map</guimenu></menuchoice>. |
| 435 |
|
</para> |
| 436 |
|
|
| 437 |
|
<itemizedlist> |
| 438 |
|
<listitem> |
| 439 |
|
<para> |
| 440 |
|
The Move Layer to Top tool |
| 441 |
|
<inlinemediaobject> |
| 442 |
|
<imageobject> |
| 443 |
|
<imagedata fileref="../images/3_5_totop.png" format="PNG" scale="&imgscale;"/> |
| 444 |
|
</imageobject> |
| 445 |
|
<imageobject> |
| 446 |
|
<imagedata fileref="./images/3_5_totop.eps" format="EPS" scale="&imgscale;"/> |
| 447 |
|
</imageobject> |
| 448 |
|
<textobject> <phrase>Move Layer to Top</phrase> </textobject> |
| 449 |
|
</inlinemediaobject> raises the selected layer to the top of the map. |
| 450 |
|
</para> |
| 451 |
|
</listitem> |
| 452 |
|
<listitem> |
| 453 |
|
|
| 454 |
|
<para> |
| 455 |
|
The Move Layer Up tool |
| 456 |
|
<inlinemediaobject> |
| 457 |
|
<imageobject> |
| 458 |
|
<imagedata fileref="../images/3_5_moveup.png" format="PNG" scale="&imgscale;"/> |
| 459 |
|
</imageobject> |
| 460 |
|
<imageobject> |
| 461 |
|
<imagedata fileref="./images/3_5_moveup.eps" format="EPS" scale="&imgscale;"/> |
| 462 |
|
</imageobject> |
| 463 |
|
<textobject> <phrase>Move Layer Up</phrase> </textobject> |
| 464 |
|
</inlinemediaobject> raises the selected layer one level. |
| 465 |
|
</para> |
| 466 |
|
</listitem> |
| 467 |
|
<listitem> |
| 468 |
|
|
| 469 |
|
<para> |
| 470 |
|
The Move Layer Down tool |
| 471 |
|
<inlinemediaobject> |
| 472 |
|
<imageobject> |
| 473 |
|
<imagedata fileref="../images/3_5_movedown.png" format="PNG" scale="&imgscale;"/> |
| 474 |
|
</imageobject> |
| 475 |
|
<imageobject> |
| 476 |
|
<imagedata fileref="./images/3_5_movedown.eps" format="EPS" scale="&imgscale;"/> |
| 477 |
|
</imageobject> |
| 478 |
|
<textobject> <phrase>Move Layer Down</phrase> </textobject> |
| 479 |
|
</inlinemediaobject> lowers the selected layer one level. |
| 480 |
|
</para> |
| 481 |
|
|
| 482 |
|
</listitem> |
| 483 |
|
<listitem> |
| 484 |
|
<para> |
| 485 |
|
The Move Layer to Bottom tool |
| 486 |
|
<inlinemediaobject> |
| 487 |
|
<imageobject> |
| 488 |
|
<imagedata fileref="../images/3_5_tobottom.png" format="PNG" scale="&imgscale;"/> |
| 489 |
|
</imageobject> |
| 490 |
|
<imageobject> |
| 491 |
|
<imagedata fileref="./images/3_5_tobottom.eps" format="EPS" scale="&imgscale;"/> |
| 492 |
|
</imageobject> |
| 493 |
|
<textobject> <phrase>Move Layer to Bottom</phrase> </textobject> |
| 494 |
|
</inlinemediaobject> lowers the selected layer to the bottom of the map. |
| 495 |
|
</para> |
| 496 |
|
|
| 497 |
|
</listitem> |
| 498 |
|
<listitem> |
| 499 |
|
<para> |
| 500 |
|
The Visible tool |
| 501 |
|
<inlinemediaobject> |
| 502 |
|
<imageobject> |
| 503 |
|
<imagedata fileref="../images/3_5_visible.png" format="PNG" scale="&imgscale;"/> |
| 504 |
|
</imageobject> |
| 505 |
|
<imageobject> |
| 506 |
|
<imagedata fileref="./images/3_5_visible.eps" format="EPS" scale="&imgscale;"/> |
| 507 |
|
</imageobject> |
| 508 |
|
<textobject> <phrase>Visible</phrase> </textobject> |
| 509 |
|
</inlinemediaobject> shows the selected layer in the map if it was |
| 510 |
|
hidden. |
| 511 |
|
</para> |
| 512 |
|
|
| 513 |
|
</listitem> |
| 514 |
|
<listitem> |
| 515 |
|
<para> |
| 516 |
|
The Invisible tool |
| 517 |
|
<inlinemediaobject> |
| 518 |
|
<imageobject> |
| 519 |
|
<imagedata fileref="../images/3_5_invisible.png" format="PNG" scale="&imgscale;"/> |
| 520 |
|
</imageobject> |
| 521 |
|
<imageobject> |
| 522 |
|
<imagedata fileref="./images/3_5_invisible.eps" format="EPS" scale="&imgscale;"/> |
| 523 |
|
</imageobject> |
| 524 |
|
<textobject> <phrase>Invisible</phrase> </textobject> |
| 525 |
|
</inlinemediaobject> hides the selected layer in the map. |
| 526 |
|
</para> |
| 527 |
|
|
| 528 |
|
</listitem> |
| 529 |
|
<listitem> |
| 530 |
|
<para> |
| 531 |
|
The Properties tool |
| 532 |
|
<inlinemediaobject> |
| 533 |
|
<imageobject> |
| 534 |
|
<imagedata fileref="../images/3_5_props.png" format="PNG" scale="&imgscale;"/> |
| 535 |
|
</imageobject> |
| 536 |
|
<imageobject> |
| 537 |
|
<imagedata fileref="./images/3_5_props.eps" format="EPS" scale="&imgscale;"/> |
| 538 |
|
</imageobject> |
| 539 |
|
<textobject> <phrase>Properties</phrase> </textobject> |
| 540 |
|
</inlinemediaobject> opens the layer's properties dialog box. |
| 541 |
|
Double-clicking on a layer or a group of a layer will open the |
| 542 |
|
properties dialog for that layer. |
| 543 |
|
</para> |
| 544 |
|
</listitem> |
| 545 |
|
</itemizedlist> |
| 546 |
|
<para> |
| 547 |
|
Along the bottom of the legend is the scalebar. The scalebar |
| 548 |
|
will be available if there are any layers and the map has a |
| 549 |
|
projection set. |
| 550 |
|
</para> |
| 551 |
|
</section> |
| 552 |
|
|
| 553 |
|
<section><title>Exporting</title> |
| 554 |
|
<para> |
| 555 |
|
Under Windows, maps can be exported in Enhanced Metafile format |
| 556 |
|
(<varname>.wmf</varname>) |
| 557 |
|
from |
| 558 |
|
<menuchoice> |
| 559 |
|
<guimenu>Map</guimenu> |
| 560 |
|
<guimenuitem>Export</guimenuitem> |
| 561 |
|
</menuchoice> for use in reports, presentations, or further |
| 562 |
|
modification. The current map view, legend, and, if available, |
| 563 |
|
scalebar are exported. Under other platforms this option is not |
| 564 |
|
available. Clicking this menu item open a file selection dialog |
| 565 |
|
that lets the user select a location to export the map. |
| 566 |
|
</para> |
| 567 |
|
</section> |
| 568 |
|
|
| 569 |
|
<section><title>Printing</title> |
| 570 |
|
<para> |
| 571 |
|
The map can be printed using |
| 572 |
|
<menuchoice> |
| 573 |
|
<guimenu>Map</guimenu> |
| 574 |
|
<guimenuitem>Print</guimenuitem> |
| 575 |
|
</menuchoice>. The current map view, legend, and, if available, |
| 576 |
|
scalebar are printed. A standard printing dialog will open allowing |
| 577 |
|
the user to configure the printer. This dialog will differ depending |
| 578 |
|
on which platform Thuban is running. |
| 579 |
|
</para> |
| 580 |
|
</section> |
| 581 |
|
|
| 582 |
|
</chapter> |
| 583 |
|
|
| 584 |
|
<chapter><title>Layer Management</title> |
| 585 |
|
<para> |
| 586 |
|
</para> |
| 587 |
|
|
| 588 |
|
<section><title>Types of Layers</title> |
| 589 |
|
<para> |
| 590 |
|
There are two types of layers supported by Thuban: shape layers and |
| 591 |
|
image layers. Shape layers consist of vector based shapes with |
| 592 |
|
geo-referenced coordinates. There are three types of supported |
| 593 |
|
shapes: polygons, lines (arc), and points. Image layers can be any image |
| 594 |
|
file format supported by the Geo-spatial Data Abstraction Library |
| 595 |
|
(GDAL). The images must have geographic |
| 596 |
|
coordinate data either embedded within the file or in a separate |
| 597 |
|
file that is in the same directory as the image file. GeoTIFF files |
| 598 |
|
work very well with Thuban and were designed specifically to be image |
| 599 |
|
layers in GIS programs. |
| 600 |
|
</para> |
| 601 |
|
<para> |
| 602 |
|
All actions in the |
| 603 |
|
<menuchoice> |
| 604 |
|
<guimenu>Layer</guimenu> |
| 605 |
|
</menuchoice> menu act on the currently selected layer in the legend. |
| 606 |
|
</para> |
| 607 |
|
</section> |
| 608 |
|
|
| 609 |
|
<section><title>Properties</title> |
| 610 |
|
<para> |
| 611 |
|
To view the properties for a layer it must first be selected in the |
| 612 |
|
legend. The menu option |
| 613 |
|
<menuchoice> |
| 614 |
|
<guimenu>Layer</guimenu> |
| 615 |
|
<guimenuitem>Properties</guimenuitem> |
| 616 |
|
</menuchoice> opens a dialog that displays a layer's properties. |
| 617 |
|
All layers have a title which can be modified in the text field |
| 618 |
|
provided. The type of layer is also shows. If the type is a type |
| 619 |
|
of shape (polygon, arc, point) the classification table will be |
| 620 |
|
shown. Image layers have no other properties other than title |
| 621 |
|
and type. |
| 622 |
|
</para> |
| 623 |
|
<para> |
| 624 |
|
<figure> |
| 625 |
|
<title>Properties Window</title> |
| 626 |
|
<mediaobject> |
| 627 |
|
<imageobject><imagedata fileref="../images/4_2_layer_properties.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 628 |
|
<imageobject><imagedata fileref="./images/4_2_layer_properties.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 629 |
|
</mediaobject> |
| 630 |
|
</figure> |
| 631 |
|
</para> |
| 632 |
|
<para> |
| 633 |
|
<figure> |
| 634 |
|
<title>Properties Window</title> |
| 635 |
|
<mediaobject> |
| 636 |
|
<imageobject><imagedata fileref="../images/4_2_raster_layer_properties.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 637 |
|
<imageobject><imagedata fileref="./images/4_2_raster_layer_properties.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 638 |
|
</mediaobject> |
| 639 |
|
</figure> |
| 640 |
|
</para> |
| 641 |
|
</section> |
| 642 |
|
|
| 643 |
|
<section><title>Visibility</title> |
| 644 |
|
<para> |
| 645 |
|
Sometimes it is not desirable to view all layers at the same time. |
| 646 |
|
Some layers may take a long time to draw and so while navigating |
| 647 |
|
around the map the user may not want to wait for the map to redraw |
| 648 |
|
all the layers each time the map is changed. Each layer can be |
| 649 |
|
independently turned on or off using the |
| 650 |
|
<menuchoice> |
| 651 |
|
<guimenu>Layer</guimenu> |
| 652 |
|
<guimenuitem>Show</guimenuitem> |
| 653 |
|
</menuchoice> |
| 654 |
|
or |
| 655 |
|
<menuchoice> |
| 656 |
|
<guimenu>Layer</guimenu> |
| 657 |
|
<guimenuitem>Hide</guimenuitem> |
| 658 |
|
</menuchoice> options respectively. |
| 659 |
|
</para> |
| 660 |
|
</section> |
| 661 |
|
|
| 662 |
|
<section><title>Duplication</title> |
| 663 |
|
<para> |
| 664 |
|
Layers and all their properties, including classifications, can |
| 665 |
|
be duplicated using |
| 666 |
|
<menuchoice> |
| 667 |
|
<guimenu>Layer</guimenu> |
| 668 |
|
<guimenuitem>Duplicate</guimenuitem> |
| 669 |
|
</menuchoice>. Duplicating a layer is useful if the user wishes |
| 670 |
|
to model a layer in several different ways. Even though the layers |
| 671 |
|
overlap, by carefully selecting the shape properties it is possible |
| 672 |
|
to display several pieces of information at once. For example, one |
| 673 |
|
copy of a roads layer may be classified on a length property and |
| 674 |
|
another copy may be classified on a type property. If the length |
| 675 |
|
property was expressed with color and the type property expressed |
| 676 |
|
with line thickness then it would be possible to view both |
| 677 |
|
classifications by placing the type property copy over the |
| 678 |
|
length property copy. |
| 679 |
|
</para> |
| 680 |
|
</section> |
| 681 |
|
|
| 682 |
|
</chapter> |
| 683 |
|
|
| 684 |
|
<chapter><title>Layer Classifications</title> |
| 685 |
|
<para> |
| 686 |
|
A layer classification is a way of assigning drawing properties to |
| 687 |
|
groups of shapes based on attributes stored in the layer's table. |
| 688 |
|
Only layer's with shapes can have a classification; image layers |
| 689 |
|
cannot be classified. |
| 690 |
|
</para> |
| 691 |
|
<para> |
| 692 |
|
A classification consists of a number of groups, each group |
| 693 |
|
having a value or range of values to match against, and symbol |
| 694 |
|
properties which control how a shape is drawn on the map. The user |
| 695 |
|
selects which field in the table is used by the classification and |
| 696 |
|
when the map is drawn the value for that field for each shape is |
| 697 |
|
compared with each group's value. The properties of the first group |
| 698 |
|
to match are used to draw the shape. This allows the user to get a |
| 699 |
|
visual impression of not only how the data is laid out but also what |
| 700 |
|
kind of data lies where. |
| 701 |
|
</para> |
| 702 |
|
<para> |
| 703 |
|
A layer always has a classification. When a new layer is added to the |
| 704 |
|
map, a default classification is created with the DEFAULT group. This |
| 705 |
|
group cannot be removed but can be hidden (see below). Every shape in the |
| 706 |
|
layer, regardless of its attributes, will match this group if no other |
| 707 |
|
group matches. |
| 708 |
|
</para> |
| 709 |
|
|
| 710 |
|
<section><title>Editing Classifications</title> |
| 711 |
|
<para> |
| 712 |
|
A layer's classification can be modified under the properties dialog |
| 713 |
|
(<menuchoice> |
| 714 |
|
<guimenu>Layer</guimenu> |
| 715 |
|
<guimenuitem>Properties</guimenuitem> |
| 716 |
|
</menuchoice>). The layer's classification field can be set to None, |
| 717 |
|
which simply assigns a DEFAULT group to the classification. No new |
| 718 |
|
groups can be added to the classification if the field is None. |
| 719 |
|
The user must first select a field to classify on. New groups can |
| 720 |
|
be added to the classification with the <guibutton>Add</guibutton> |
| 721 |
|
button. |
| 722 |
|
</para> |
| 723 |
|
<para> |
| 724 |
|
To apply the changes to the map the user can click |
| 725 |
|
either <guibutton>Try</guibutton> or <guibutton>OK</guibutton>. |
| 726 |
|
<guibutton>Try</guibutton> will not close the dialog box, allowing |
| 727 |
|
the user to see how the classification changes the map. |
| 728 |
|
<guibutton>Revert</guibutton> will undo the last classification applied |
| 729 |
|
to the map. <guibutton>OK</guibutton> will commit the changes and |
| 730 |
|
close the dialog. The user will be unable to undo the changes. |
| 731 |
|
<guibutton>Close</guibutton> simply closes the dialog box. If any |
| 732 |
|
changes have not been applied with <guibutton>Try</guibutton> the |
| 733 |
|
changes will not be applied to the map. |
| 734 |
|
</para> |
| 735 |
|
<para> |
| 736 |
|
<figure> |
| 737 |
|
<title>Properties Window</title> |
| 738 |
|
<mediaobject> |
| 739 |
|
<imageobject><imagedata fileref="../images/5_classification.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 740 |
|
<imageobject><imagedata fileref="./images/5_classification.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 741 |
|
</mediaobject> |
| 742 |
|
</figure> |
| 743 |
|
</para> |
| 744 |
|
<para> |
| 745 |
|
The order of the groups in the classification is significant |
| 746 |
|
except for the DEFAULT group, which remains at the top. When shapes |
| 747 |
|
are matched against groups the matching begins at the first group |
| 748 |
|
after the DEFAULT group so that groups higher in the list will |
| 749 |
|
be checked first. Matching for a |
| 750 |
|
given shape will stop at the first group that matches. The user can |
| 751 |
|
use <guibutton>Move Up</guibutton> and <guibutton>Move Down</guibutton> |
| 752 |
|
to change the order of the groups. The DEFAULT group will always |
| 753 |
|
match a shape that hasn't matched another group. |
| 754 |
|
</para> |
| 755 |
|
<section><title>Visible</title> |
| 756 |
|
<para> |
| 757 |
|
The Visible column has check-boxes that determine whether a |
| 758 |
|
classification group will be displayed in the legend. This is |
| 759 |
|
useful if the user knows that the groups completely cover |
| 760 |
|
the data set and don't want the DEFAULT group to be displayed |
| 761 |
|
in the legend and on a printout. |
| 762 |
|
</para> |
| 763 |
|
</section> |
| 764 |
|
<section><title>Symbols</title> |
| 765 |
|
<para> |
| 766 |
|
Each type of shape has its own type of symbol. Thuban supports three |
| 767 |
|
types of shapes: polygons, lines, and points. Polygons and points |
| 768 |
|
have outline and fill color, while lines have only line color. Each |
| 769 |
|
group has associated symbol properties. To edit the symbol |
| 770 |
|
properties for a group the user can double click on the Symbol |
| 771 |
|
column or select a group and click the |
| 772 |
|
<guibutton>Edit Symbol</guibutton> button. |
| 773 |
|
</para> |
| 774 |
|
</section> |
| 775 |
|
<section><title>Value</title> |
| 776 |
|
<para> |
| 777 |
|
The Value column of the classification table is the value that will |
| 778 |
|
be matched when the map is being drawn. The type of data that can |
| 779 |
|
entered into this field depends on the type of data of the |
| 780 |
|
classification field. |
| 781 |
|
</para> |
| 782 |
|
<para> |
| 783 |
|
If the field is of type Text, anything entered |
| 784 |
|
into the field is valid. The text will be compared literally to the |
| 785 |
|
value of the shape attribute, including case sensitivity. |
| 786 |
|
If the type is Integer, then any valid integer may be entered. In |
| 787 |
|
addition, with special syntax, a range of values can be entered. |
| 788 |
|
A range from <varname>start</varname> to <varname>end</varname> |
| 789 |
|
inclusive is specified like this: <literal>[start;end]</literal>. |
| 790 |
|
The exclusive range is specified like this: |
| 791 |
|
<literal>]start;end[</literal>. Ranges can include infinity like |
| 792 |
|
this: <literal>[-oo;oo]</literal>. Field types can also be of type |
| 793 |
|
Decimal. They represent any rational number and can be used in |
| 794 |
|
ranges as well. |
| 795 |
|
</para> |
| 796 |
|
</section> |
| 797 |
|
<section><title>Label</title> |
| 798 |
|
<para> |
| 799 |
|
By default, the text that is displayed for a group in the legend |
| 800 |
|
is the value for that group. The label can substitute a more |
| 801 |
|
descriptive term in the legend. |
| 802 |
|
</para> |
| 803 |
|
</section> |
| 804 |
|
</section> |
| 805 |
|
|
| 806 |
|
<section><title>Generating Classes</title> |
| 807 |
|
<para> |
| 808 |
|
<figure> |
| 809 |
|
<title>Generate Class</title> |
| 810 |
|
<mediaobject> |
| 811 |
|
<imageobject><imagedata fileref="../images/5_3_genclass.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 812 |
|
<imageobject><imagedata fileref="./images/5_3_genclass.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 813 |
|
</mediaobject> |
| 814 |
|
</figure> |
| 815 |
|
</para> |
| 816 |
|
<para> |
| 817 |
|
Creating a classification by hand can be tedious. |
| 818 |
|
Thuban, therefore, provides a means of generating an entire |
| 819 |
|
classification at once while still giving the user control over |
| 820 |
|
how it appears. Clicking <guibutton>Generate Class</guibutton> |
| 821 |
|
opens the <varname>Generate Classification</varname> dialog. |
| 822 |
|
Under the <varname>Generate</varname> pull down there are at most |
| 823 |
|
three different ways to generate classifications: |
| 824 |
|
Unique Values, Uniform Distribution, and Quantiles. Some options |
| 825 |
|
may not be available if the data type for the field does not |
| 826 |
|
support them. For instance, <varname>Uniform Distribution</varname> |
| 827 |
|
doesn't make sense for a Text field. |
| 828 |
|
</para> |
| 829 |
|
<para> |
| 830 |
|
For every way of generating a classification, a color scheme must |
| 831 |
|
be selected. Thuban provides several different color schemes that |
| 832 |
|
affect how the group properties change over the classification. |
| 833 |
|
It may be desirable that only certain properties change over the |
| 834 |
|
classification. If the shape type is a polygon or a point then |
| 835 |
|
the <guibutton>Fix Border Color</guibutton> option will be available. |
| 836 |
|
This allows the user to select a border color for all classification |
| 837 |
|
groups. |
| 838 |
|
It is also possible to create a custom color scheme. Selecting |
| 839 |
|
this option will display two symbols: the one of the left has the |
| 840 |
|
properties of the first group and the one on the right has the |
| 841 |
|
properties of the last group. Thuban will interpolate between these |
| 842 |
|
two properties to generate the other groups. |
| 843 |
|
<figure> |
| 844 |
|
<title>Custom Color Scheme</title> |
| 845 |
|
<mediaobject> |
| 846 |
|
<imageobject><imagedata fileref="../images/5_2_custom_ramp.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 847 |
|
<imageobject><imagedata fileref="./images/5_2_custom_ramp.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 848 |
|
</mediaobject> |
| 849 |
|
</figure> |
| 850 |
|
</para> |
| 851 |
|
<para> |
| 852 |
|
The Unique Values option lets the user select specific values that |
| 853 |
|
appear in the table. Clicking <guibutton>Retrieve From Table</guibutton> |
| 854 |
|
searches the table for all unique values and displays them in the |
| 855 |
|
list on the left. Items can be selected and moved to the list on the |
| 856 |
|
right. Each list can be sorted or reversed for easier searching. |
| 857 |
|
The classification that is generated will be in the same order as |
| 858 |
|
the list on the right. |
| 859 |
|
<figure> |
| 860 |
|
<title>Unique Values</title> |
| 861 |
|
<mediaobject> |
| 862 |
|
<imageobject><imagedata fileref="../images/5_2_unique_values.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 863 |
|
<imageobject><imagedata fileref="./images/5_2_unique_values.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 864 |
|
</mediaobject> |
| 865 |
|
</figure> |
| 866 |
|
</para> |
| 867 |
|
<para> |
| 868 |
|
The Uniform Distribution option creates a user specified number of |
| 869 |
|
groups of ranges such that each range covers equal intervals. The |
| 870 |
|
minimum and maximum values can automatically be retrieved from the |
| 871 |
|
table by clicking <guibutton>Retrieve From Table</guibutton>. The |
| 872 |
|
stepping is how large each interval is. Adjusting this value will |
| 873 |
|
automatically recalculate how many groups is appropriate. |
| 874 |
|
<figure> |
| 875 |
|
<title>Uniform Distribution</title> |
| 876 |
|
<mediaobject> |
| 877 |
|
<imageobject><imagedata fileref="../images/5_2_uniform_dist.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 878 |
|
<imageobject><imagedata fileref="./images/5_2_uniform_dist.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 879 |
|
</mediaobject> |
| 880 |
|
</figure> |
| 881 |
|
</para> |
| 882 |
|
<para> |
| 883 |
|
The Quantiles option generates ranges based on the number of items |
| 884 |
|
in the table. For example, by specifying five groups Thuban will |
| 885 |
|
generate five groups with appropriate ranges such that 20% of the table |
| 886 |
|
data is in each group. If it is impossible to generate exact |
| 887 |
|
groupings, Thuban will issue a warning but allow the user to continue. |
| 888 |
|
<figure> |
| 889 |
|
<title>Quantiles</title> |
| 890 |
|
<mediaobject> |
| 891 |
|
<imageobject><imagedata fileref="../images/5_2_quantiles.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 892 |
|
<imageobject><imagedata fileref="./images/5_2_quantiles.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 893 |
|
</mediaobject> |
| 894 |
|
</figure> |
| 895 |
|
</para> |
| 896 |
|
</section> |
| 897 |
|
</chapter> |
| 898 |
|
|
| 899 |
|
<chapter><title>Projection Management</title> |
| 900 |
|
<para> |
| 901 |
|
Projections control how the geographic data is displayed on the screen. |
| 902 |
|
If multiple layers are loaded into Thuban where the geographic data |
| 903 |
|
is in a different projection system, then the user must specify a |
| 904 |
|
projection for each layer. The user must also tell Thuban which |
| 905 |
|
projection the map is in. This can be the same as the layers or a different |
| 906 |
|
projection in which case the layers are reprojected into that space. |
| 907 |
|
The map projection can be set using |
| 908 |
|
<menuchoice> |
| 909 |
|
<guimenu>Map</guimenu> |
| 910 |
|
<guimenuitem>Projection</guimenuitem> |
| 911 |
|
</menuchoice> and the layer projection can be set using |
| 912 |
|
<menuchoice> |
| 913 |
|
<guimenu>Layer</guimenu> |
| 914 |
|
<guimenuitem>Projection</guimenuitem> |
| 915 |
|
</menuchoice>. |
| 916 |
|
<figure> |
| 917 |
|
<title>Projection Window</title> |
| 918 |
|
<mediaobject> |
| 919 |
|
<imageobject><imagedata fileref="../images/6_projection.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 920 |
|
<imageobject><imagedata fileref="./images/6_projection.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 921 |
|
</mediaobject> |
| 922 |
|
</figure> |
| 923 |
|
</para> |
| 924 |
|
<para> |
| 925 |
|
Thuban is distributed with a sample collection of projections. The |
| 926 |
|
user can create new projections and make them available to all |
| 927 |
|
future Thuban sessions. They may also be exported and imported so |
| 928 |
|
that custom projections can be distributed. |
| 929 |
|
</para> |
| 930 |
|
<section><title>Selecting a Projection</title> |
| 931 |
|
<para> |
| 932 |
|
The available projections are listed on the left. If the layer |
| 933 |
|
or map already has a projection it will initially be highlighted |
| 934 |
|
and will end with <varname>(current)</varname>. Selecting |
| 935 |
|
<varname><None></varname> will cause Thuban to use the data as |
| 936 |
|
it appears in the source file and will not use a projection. |
| 937 |
|
</para> |
| 938 |
|
</section> |
| 939 |
|
<section><title>Editing a Projection</title> |
| 940 |
|
<para> |
| 941 |
|
Whenever a projection is selected from the list its properties |
| 942 |
|
are displayed on the right. These properties can be changed |
| 943 |
|
and the changes saved to the selected projection using |
| 944 |
|
<guibutton>Update</guibutton>. Only a projection that comes |
| 945 |
|
from a file can be updated, so if the current layer's projection |
| 946 |
|
is selected, <guibutton>Update</guibutton> will be disabled. |
| 947 |
|
<guibutton>Add to List</guibutton> adds the projection to the |
| 948 |
|
list of available projections as a new entry, and thus makes it |
| 949 |
|
available to future Thuban sessions. Clicking <guibutton>New</guibutton> |
| 950 |
|
will create an entirely new, empty projection. The |
| 951 |
|
<guibutton>Remove</guibutton> button will permanently remove a |
| 952 |
|
projection from the list of available projections. |
| 953 |
|
</para> |
| 954 |
|
<para> |
| 955 |
|
To apply the selected projection to the map the user can click |
| 956 |
|
either <guibutton>Try</guibutton> or <guibutton>OK</guibutton>. |
| 957 |
|
<guibutton>Try</guibutton> will not close the dialog box, allowing |
| 958 |
|
the user to see how the projeciton changes the map. |
| 959 |
|
<guibutton>Revert</guibutton> will undo the last projection applied |
| 960 |
|
to the map. <guibutton>OK</guibutton> will commit the changes and |
| 961 |
|
close the dialog. The user will be unable to undo the changes. |
| 962 |
|
<guibutton>Close</guibutton> simply closes the dialog box. If no |
| 963 |
|
selection has been applied with <guibutton>Try</guibutton> the |
| 964 |
|
selection will not be applied to the map. |
| 965 |
|
</para> |
| 966 |
|
</section> |
| 967 |
|
<section><title>Importing/Exporting Projections</title> |
| 968 |
|
<para> |
| 969 |
|
The projections that appear in the list of available projections |
| 970 |
|
can be exported to another file that the user chooses. By selecting |
| 971 |
|
one or more projections and clicking <guibutton>Export</guibutton> |
| 972 |
|
the user will be able to select a file in which to store those |
| 973 |
|
projections. |
| 974 |
|
The file can then be distributed to other Thuban users. To import |
| 975 |
|
a projection file the user can click <guibutton>Import</guibutton>. |
| 976 |
|
The imported projections are added to the list and are then available |
| 977 |
|
to the current session and any future Thuban sessions. |
| 978 |
|
</para> |
| 979 |
|
</section> |
| 980 |
|
</chapter> |
| 981 |
|
|
| 982 |
|
<chapter><title>Table Management</title> |
| 983 |
|
<para> |
| 984 |
|
Thuban distinguishes two different types of tables: Attribute tables |
| 985 |
|
(which belong to a layer) and normal data tables. Both provide |
| 986 |
|
the same general functionality with the difference that actions on an |
| 987 |
|
attribute table might also effect the map display. |
| 988 |
|
</para> |
| 989 |
|
|
| 990 |
|
<section><title>Table View</title> |
| 991 |
|
<para> |
| 992 |
|
<figure> |
| 993 |
|
<title>Table View</title> |
| 994 |
|
<mediaobject> |
| 995 |
|
<imageobject><imagedata fileref="../images/7_1_table_view.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 996 |
|
<imageobject><imagedata fileref="./images/7_1_table_view.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 997 |
|
</mediaobject> |
| 998 |
|
</figure> |
| 999 |
|
</para> |
| 1000 |
|
<para> |
| 1001 |
|
Thuban provides a standard dialog to display table contents, the |
| 1002 |
|
Table View. The view has five sections: The title, selections, |
| 1003 |
|
the table grid, export functions, and the status bar. |
| 1004 |
|
</para> |
| 1005 |
|
<para> |
| 1006 |
|
The title bar identifies the table with its name. |
| 1007 |
|
</para> |
| 1008 |
|
<para> |
| 1009 |
|
The selections box let the user perform simple analysis on the data |
| 1010 |
|
based on comparisons: The first choice must be a field identifier of |
| 1011 |
|
the table, the second choice determines the type of comparison. The |
| 1012 |
|
third choice can be either a specific value (interpreted as numerical |
| 1013 |
|
or string depending on the type of the first field) or a second field |
| 1014 |
|
identifier. Thus you can perform analysis like selecting all |
| 1015 |
|
records where <literal>population > 10000</literal> or |
| 1016 |
|
<literal>cars_per_inhabitant < bikes_per_inhabitant</literal> |
| 1017 |
|
(note that the field names are only explanatory, the dBase files |
| 1018 |
|
allow only 11 character field names). |
| 1019 |
|
|
| 1020 |
|
Selections can be combined either by applying a selection only on |
| 1021 |
|
a previously selected set of records or by adding the results of a |
| 1022 |
|
selection to a previous set. The default is that a selection replaces |
| 1023 |
|
earlier results. |
| 1024 |
|
</para> |
| 1025 |
|
<para> |
| 1026 |
|
The table grid shows the contents of the table (one record per row), |
| 1027 |
|
with highlighted selection results. Columns and rows can be resized. |
| 1028 |
|
</para> |
| 1029 |
|
<para> |
| 1030 |
|
The contents of a table can be exported into a file, either dBase |
| 1031 |
|
format (DBF) or comma separated values (CSV). The |
| 1032 |
|
<guibutton>Export</guibutton> button |
| 1033 |
|
raises a file dialog to specify a path and file name, the export type |
| 1034 |
|
is determined by the file extension (either .dbf or .csv). |
| 1035 |
|
|
| 1036 |
|
The <guibutton>Export Selection</guibutton> button works similarly |
| 1037 |
|
but exports only the selected records. |
| 1038 |
|
|
| 1039 |
|
The <guibutton>Close</guibutton> button closes the table view window. |
| 1040 |
|
This is different from the menu item |
| 1041 |
|
<menuchoice> |
| 1042 |
|
<guimenu>Table</guimenu> |
| 1043 |
|
<guimenuitem>Close</guimenuitem> |
| 1044 |
|
</menuchoice> which unloads the table from Thuban. |
| 1045 |
|
</para> |
| 1046 |
|
<para> |
| 1047 |
|
The status bar displays some statistics about the table and optional |
| 1048 |
|
selection results. |
| 1049 |
|
</para> |
| 1050 |
|
</section> |
| 1051 |
|
|
| 1052 |
|
<section><title>General Functionality (Menu Table)</title> |
| 1053 |
|
<para> |
| 1054 |
|
The general functions affect all tables open in Thuban. Attribute |
| 1055 |
|
tables are considered here as normal data tables (with the exception |
| 1056 |
|
that they cannot be closed). |
| 1057 |
|
</para> |
| 1058 |
|
<section><title>Open</title> |
| 1059 |
|
<para> |
| 1060 |
|
The |
| 1061 |
|
<menuchoice> |
| 1062 |
|
<guimenu>Table</guimenu> |
| 1063 |
|
<guimenuitem>Open</guimenuitem> |
| 1064 |
|
</menuchoice> |
| 1065 |
|
item raises a file dialog to let you select a |
| 1066 |
|
dBase file from the file system to be loaded into Thuban read-only. |
| 1067 |
|
On <guibutton>OK</guibutton> the selected file is loaded and a |
| 1068 |
|
table view is opened. |
| 1069 |
|
</para> |
| 1070 |
|
</section> |
| 1071 |
|
|
| 1072 |
|
<section><title>Close</title> |
| 1073 |
|
<para> |
| 1074 |
|
The |
| 1075 |
|
<menuchoice> |
| 1076 |
|
<guimenu>Table</guimenu> |
| 1077 |
|
<guimenuitem>Close</guimenuitem> |
| 1078 |
|
</menuchoice> |
| 1079 |
|
item raises a dialog listing the currently open |
| 1080 |
|
data tables |
| 1081 |
|
(loaded via |
| 1082 |
|
<menuchoice> |
| 1083 |
|
<guimenu>Table</guimenu> |
| 1084 |
|
<guimenuitem>Open</guimenuitem> |
| 1085 |
|
</menuchoice>). Selected tables are dereferenced on confirmation. |
| 1086 |
|
Since tables are opened read-only the contents of the tables are |
| 1087 |
|
not affected. |
| 1088 |
|
|
| 1089 |
|
Any open views of the tables are closed as well. |
| 1090 |
|
|
| 1091 |
|
Tables used in a join cannot be closed. |
| 1092 |
|
</para> |
| 1093 |
|
</section> |
| 1094 |
|
|
| 1095 |
|
<section><title>Rename</title> |
| 1096 |
|
<para> |
| 1097 |
|
<menuchoice> |
| 1098 |
|
<guimenu>Table</guimenu> |
| 1099 |
|
<guimenuitem>Rename</guimenuitem> |
| 1100 |
|
</menuchoice> changes the table title. |
| 1101 |
|
</para> |
| 1102 |
|
</section> |
| 1103 |
|
|
| 1104 |
|
<section><title>Show</title> |
| 1105 |
|
<para> |
| 1106 |
|
The |
| 1107 |
|
<menuchoice> |
| 1108 |
|
<guimenu>Table</guimenu> |
| 1109 |
|
<guimenuitem>Show</guimenuitem> |
| 1110 |
|
</menuchoice> |
| 1111 |
|
item raises a list of available tables (explicitly |
| 1112 |
|
loaded, attribute tables, results of a join). Selected tables are |
| 1113 |
|
show in tables views on <guibutton>OK</guibutton>. |
| 1114 |
|
</para> |
| 1115 |
|
</section> |
| 1116 |
|
|
| 1117 |
|
<section><title>Join</title> |
| 1118 |
|
<para> |
| 1119 |
|
<figure> |
| 1120 |
|
<title>Join Tables</title> |
| 1121 |
|
<mediaobject> |
| 1122 |
|
<imageobject><imagedata fileref="../images/7_2_5_join.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 1123 |
|
<imageobject><imagedata fileref="./images/7_2_5_join.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 1124 |
|
</mediaobject> |
| 1125 |
|
</figure> |
| 1126 |
|
</para> |
| 1127 |
|
<para> |
| 1128 |
|
The |
| 1129 |
|
<menuchoice> |
| 1130 |
|
<guimenu>Table</guimenu> |
| 1131 |
|
<guimenuitem>Join</guimenuitem> |
| 1132 |
|
</menuchoice> |
| 1133 |
|
item raises a dialog to specify the two tables to be |
| 1134 |
|
joined. The join results in a new table named 'Join of "left table" |
| 1135 |
|
and "right table"'. |
| 1136 |
|
|
| 1137 |
|
The dialog lets you select the two tables to be joined and the two |
| 1138 |
|
fields the join has to be performed on. By default, the new |
| 1139 |
|
table contains only those records which are matched by the join. |
| 1140 |
|
|
| 1141 |
|
If you want to preserve the records of the left table you can |
| 1142 |
|
perform an outer join. The fields from the right table for records |
| 1143 |
|
not matched by the join are filled with <varname>None</varname> in |
| 1144 |
|
this case. |
| 1145 |
|
</para> |
| 1146 |
|
</section> |
| 1147 |
|
|
| 1148 |
|
</section> |
| 1149 |
|
<section><title>Attribute Tables</title> |
| 1150 |
|
<para> |
| 1151 |
|
To clearly separate between both types of tables (data and |
| 1152 |
|
attribute), Thuban provides functionality regarding the attribute |
| 1153 |
|
tables under the <menuchoice><guimenu>Layer</guimenu></menuchoice> menu. |
| 1154 |
|
</para> |
| 1155 |
|
|
| 1156 |
|
<section><title>Show Table</title> |
| 1157 |
|
<para> |
| 1158 |
|
<menuchoice> |
| 1159 |
|
<guimenu>Layer</guimenu> |
| 1160 |
|
<guimenuitem>Show Table</guimenuitem> |
| 1161 |
|
</menuchoice> |
| 1162 |
|
opens the attribute table of the currently active layer in a table |
| 1163 |
|
view. |
| 1164 |
|
|
| 1165 |
|
In addition to the functionality described above selections |
| 1166 |
|
affect also the map display: objects related to selected records |
| 1167 |
|
are highlighted. |
| 1168 |
|
</para> |
| 1169 |
|
</section> |
| 1170 |
|
|
| 1171 |
|
<section><title>Join Table</title> |
| 1172 |
|
<para> |
| 1173 |
|
Unlike the join described above, the join does not result in a |
| 1174 |
|
new table. The attribute table of the currently active layer is the |
| 1175 |
|
left table and other tables are joined to this table. The results of |
| 1176 |
|
the join are available for classification. |
| 1177 |
|
|
| 1178 |
|
As a consequence, the join cannot result in fewer |
| 1179 |
|
records than the source attribute table. The user is warned if the |
| 1180 |
|
right table does not fulfill this constraint. An outer join must be |
| 1181 |
|
used in such cases. |
| 1182 |
|
</para> |
| 1183 |
|
</section> |
| 1184 |
|
|
| 1185 |
|
<section><title>Unjoin Table</title> |
| 1186 |
|
<para> |
| 1187 |
|
As said above, a normal table cannot be closed while it is still |
| 1188 |
|
used in a join. While the joined table resulting from a join of |
| 1189 |
|
normal tables can be simply closed (and thereby dereferencing |
| 1190 |
|
the source tables), this is not possible for attribute tables. |
| 1191 |
|
|
| 1192 |
|
Hence joins on attribute tables must be solved explicitly. This is |
| 1193 |
|
what the |
| 1194 |
|
<menuchoice> |
| 1195 |
|
<guimenu>Layer</guimenu> |
| 1196 |
|
<guimenuitem>Unjoin Table</guimenuitem> |
| 1197 |
|
</menuchoice> |
| 1198 |
|
item is used for: The last join for the currently |
| 1199 |
|
active layer is solved. |
| 1200 |
|
</para> |
| 1201 |
|
</section> |
| 1202 |
|
</section> |
| 1203 |
|
</chapter> |
| 1204 |
|
|
| 1205 |
|
<chapter><title>Trouble Shooting</title> |
| 1206 |
|
<para> |
| 1207 |
|
Here are a few problems that users have encountered when first using Thuban. |
| 1208 |
|
</para> |
| 1209 |
|
<para> |
| 1210 |
|
|
| 1211 |
|
<itemizedlist> |
| 1212 |
|
<listitem> |
| 1213 |
|
<para>After adding two or more layers nothing is drawn in the map window. |
| 1214 |
|
</para> |
| 1215 |
|
<para> |
| 1216 |
|
This is probably because the layers have different projections. Projections |
| 1217 |
|
must be set on all layers and on the map itself if the layers' projections |
| 1218 |
|
are different. |
| 1219 |
|
</para> |
| 1220 |
|
</listitem> |
| 1221 |
|
|
| 1222 |
|
<listitem> |
| 1223 |
|
<para>Thuban crashes on startup with the error |
| 1224 |
|
<literal>NameError: global name 'False' is not defined</literal>. |
| 1225 |
|
</para> |
| 1226 |
|
<para> |
| 1227 |
|
<varname>True</varname> and <varname>False</varname> were only introduced |
| 1228 |
|
in Python 2.2.1. Thuban depends on at least Python 2.2.1. |
| 1229 |
|
</para> |
| 1230 |
|
</listitem> |
| 1231 |
|
|
| 1232 |
|
<listitem> |
| 1233 |
|
<para>After compiling Thuban, Thuban crashes with an error similar to |
| 1234 |
|
<literal> |
| 1235 |
|
ImportError: /usr/local//lib/thuban/Thuban/../Lib/wxproj.so: undefined symbol: __gxx_personality_v0 |
| 1236 |
|
</literal> |
| 1237 |
|
</para> |
| 1238 |
|
<para> |
| 1239 |
|
Thuban depends on the wxWindows library. If Thuban is compiled with an |
| 1240 |
|
incompatible version of the compiler than wxWindows was compiled with |
| 1241 |
|
this error may occur. Try compiling with a different version of the |
| 1242 |
|
compiler. |
| 1243 |
|
</para> |
| 1244 |
|
</listitem> |
| 1245 |
|
</itemizedlist> |
| 1246 |
|
</para> |
| 1247 |
|
<para> |
| 1248 |
|
If an error occurs Thuban will display a dialog indicating the error |
| 1249 |
|
before closing. The text should be copied and reported to the |
| 1250 |
|
<ulink url="http://thuban.intevation.org/bugtracker.html"> |
| 1251 |
|
Intevation bugtracker |
| 1252 |
|
</ulink>. |
| 1253 |
|
More information about the system is available from |
| 1254 |
|
<menuchoice><guimenu>Help</guimenu><guimenuitem>About</guimenuitem></menuchoice> box. |
| 1255 |
|
This should also be included in the bug report. |
| 1256 |
|
<figure> |
| 1257 |
|
<title>Error Dialog</title> |
| 1258 |
|
<mediaobject> |
| 1259 |
|
<imageobject><imagedata fileref="../images/8_int_error.png" format="PNG" scale="&imgscale;"/></imageobject> |
| 1260 |
|
<imageobject><imagedata fileref="./images/8_int_error.eps" format="EPS" scale="&imgscale;"/></imageobject> |
| 1261 |
|
</mediaobject> |
| 1262 |
|
</figure> |
| 1263 |
|
</para> |
| 1264 |
|
|
| 1265 |
|
</chapter> |
| 1266 |
|
|
| 1267 |
|
<appendix><title>Supported Data Sources</title> |
| 1268 |
|
<para> |
| 1269 |
|
</para> |
| 1270 |
|
<variablelist> |
| 1271 |
|
<varlistentry> |
| 1272 |
|
<term>Shapefile</term> |
| 1273 |
|
<listitem> |
| 1274 |
|
<para> |
| 1275 |
|
The Shapefile format has become a standard format for saving |
| 1276 |
|
geographic vector information. It supports polygons, lines, and |
| 1277 |
|
points. |
| 1278 |
|
|
| 1279 |
|
<ulink url="http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf"> |
| 1280 |
|
Technical Specification. |
| 1281 |
|
</ulink> |
| 1282 |
|
</para> |
| 1283 |
|
</listitem> |
| 1284 |
|
</varlistentry> |
| 1285 |
|
|
| 1286 |
|
<varlistentry> |
| 1287 |
|
<term>dBase file</term> |
| 1288 |
|
<listitem> |
| 1289 |
|
<para> |
| 1290 |
|
dBase files are used to store the attributes for each layer. This |
| 1291 |
|
is closely associated with the Shapefile format. For detailed |
| 1292 |
|
specifications on the correct format of a dBase file used with |
| 1293 |
|
Thuban please see the Technical Specification for the Shapefile |
| 1294 |
|
format above. |
| 1295 |
|
</para> |
| 1296 |
|
</listitem> |
| 1297 |
|
</varlistentry> |
| 1298 |
|
|
| 1299 |
|
<varlistentry> |
| 1300 |
|
<term>Raster files</term> |
| 1301 |
|
<listitem> |
| 1302 |
|
<para> |
| 1303 |
|
Binding the GDAL library Thuban supports numerous raster file formats, |
| 1304 |
|
see <ulink url="http://www.remotesensing.org/gdal/formats_list.html"> |
| 1305 |
|
GDAL format list</ulink> for details.</para> |
| 1306 |
|
|
| 1307 |
|
<para>Most commonly used is the <emphasis>TIFF/GeoTIFF</emphasis> |
| 1308 |
|
format: Raster maps are provided as TIFF images, with an additional |
| 1309 |
|
"world file" storing the geographic reference (usually with an |
| 1310 |
|
extension ".tfw"). |
| 1311 |
|
</para> |
| 1312 |
|
</listitem> |
| 1313 |
|
</varlistentry> |
| 1314 |
|
|
| 1315 |
|
</variablelist> |
| 1316 |
|
</appendix> |
| 1317 |
|
|
| 1318 |
|
<appendix><title>Supported Projections</title> |
| 1319 |
|
<para> |
| 1320 |
|
The following types of projections are directly support by |
| 1321 |
|
Thuban. The specific values for each are provided by the user |
| 1322 |
|
to create custom projections. Thuban comes with predefined |
| 1323 |
|
projections which are available through the Projections dialog. |
| 1324 |
|
</para> |
| 1325 |
|
<itemizedlist> |
| 1326 |
|
<listitem> |
| 1327 |
|
<para>Geographic</para> |
| 1328 |
|
<itemizedlist> |
| 1329 |
|
<listitem><para><literal>Ellipsoid</literal></para></listitem> |
| 1330 |
|
<listitem><para> |
| 1331 |
|
<literal>Source Data</literal>: either Degrees or Radians |
| 1332 |
|
</para></listitem> |
| 1333 |
|
</itemizedlist> |
| 1334 |
|
</listitem> |
| 1335 |
|
<listitem> |
| 1336 |
|
<para>Lambert Conic Conformal</para> |
| 1337 |
|
<itemizedlist> |
| 1338 |
|
<listitem><para><literal>Ellipsoid</literal></para></listitem> |
| 1339 |
|
<listitem><para><literal>Latitude of 1st standard parallel</literal></para></listitem> |
| 1340 |
|
<listitem><para><literal>Latitude of 2nd standard parallel</literal></para></listitem> |
| 1341 |
|
<listitem><para><literal>Central Meridian</literal></para></listitem> |
| 1342 |
|
<listitem><para><literal>Latitude of Origin</literal></para></listitem> |
| 1343 |
|
<listitem><para><literal>False Easting</literal> (meters)</para></listitem> |
| 1344 |
|
<listitem><para><literal>False Northing</literal> (meters)</para></listitem> |
| 1345 |
|
</itemizedlist> |
| 1346 |
|
</listitem> |
| 1347 |
|
<listitem> |
| 1348 |
|
<para>Transverse Mercator</para> |
| 1349 |
|
<itemizedlist> |
| 1350 |
|
<listitem><para><literal>Ellipsoid</literal></para></listitem> |
| 1351 |
|
<listitem><para><literal>Latitude</literal>of origin</para></listitem> |
| 1352 |
|
<listitem><para><literal>Longitude</literal>at central meridian</para></listitem> |
| 1353 |
|
<listitem><para><literal>Scale Factor</literal>at central meridian</para></listitem> |
| 1354 |
|
<listitem><para><literal>False Easting</literal> (meters)</para></listitem> |
| 1355 |
|
<listitem><para><literal>False Northing</literal> (meters)</para></listitem> |
| 1356 |
|
</itemizedlist> |
| 1357 |
|
</listitem> |
| 1358 |
|
<listitem> |
| 1359 |
|
<para>Universal Transverse Mercator</para> |
| 1360 |
|
<itemizedlist> |
| 1361 |
|
<listitem><para><literal>Ellipsoid</literal></para></listitem> |
| 1362 |
|
<listitem><para><literal>Zone</literal> |
| 1363 |
|
(can be guessed appling the Propose button)</para></listitem> |
| 1364 |
|
<listitem><para><literal>Southern Hemisphere</literal> flag</para></listitem> |
| 1365 |
|
</itemizedlist> |
| 1366 |
|
</listitem> |
| 1367 |
|
</itemizedlist> |
| 1368 |
|
|
| 1369 |
|
<para> |
| 1370 |
|
Thuban comes with a sample set of map projections for various |
| 1371 |
|
European countries. Apart from the basic projection they differ |
| 1372 |
|
especially in their parameterization: |
| 1373 |
|
</para> |
| 1374 |
|
<itemizedlist> |
| 1375 |
|
<listitem><para>Belgium Datum 1972 (Lambert Conic Conformal)</para> |
| 1376 |
|
</listitem> |
| 1377 |
|
|
| 1378 |
|
<listitem><para>Gauss-Boaga Zone 1 (Italy, Transverse Mercartor)</para> |
| 1379 |
|
</listitem> |
| 1380 |
|
|
| 1381 |
|
<listitem><para>Gauss-Krueger Zone 2 (Germany, Transverse Mercartor) |
| 1382 |
|
</para> |
| 1383 |
|
</listitem> |
| 1384 |
|
|
| 1385 |
|
<listitem><para>Reseau Geodesique Francaise |
| 1386 |
|
(France, Lambert Conic Conformal)</para> |
| 1387 |
|
</listitem> |
| 1388 |
|
|
| 1389 |
|
<listitem><para>UK National Grid (United Kingdom, Transverse Mercartor) |
| 1390 |
|
</para> |
| 1391 |
|
</listitem> |
| 1392 |
|
</itemizedlist> |
| 1393 |
|
|
| 1394 |
|
<para> |
| 1395 |
|
Thuban uses the comprehensive PROJ library for projections. PROJ provides |
| 1396 |
|
more than the four commonly used projections described above. If needed |
| 1397 |
|
Thuban can be easily extended to a new projection covered by PROJ. |
| 1398 |
|
</para> |
| 1399 |
|
</appendix> |
| 1400 |
|
|
| 1401 |
</book> |
</book> |
| 1402 |
|
|
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