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<!-- $Revision$ --> |
<!-- $Revision$ --> |
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<book> |
<book> |
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<bookinfo> |
<bookinfo> |
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<title>Thuban Manual</title> |
<title>User's Manual for Thuban 1.0</title> |
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<author> |
<authorgroup> |
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<firstname>Jonathan</firstname><surname>Coles</surname> |
<author> |
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</author> |
<firstname>Jonathan</firstname><surname>Coles</surname> |
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<author> |
</author> |
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<firstname>Jan-Oliver</firstname><surname>Wagner</surname> |
<author> |
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</author> |
<firstname>Jan-Oliver</firstname><surname>Wagner</surname> |
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<author> |
</author> |
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<firstname>Frank</firstname><surname>Koormann</surname> |
<author> |
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</author> |
<firstname>Frank</firstname><surname>Koormann</surname> |
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|
</author> |
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|
</authorgroup> |
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<copyright> |
<copyright> |
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<year>2003</year> |
<year>2003</year> |
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<holder>Intevation GmbH</holder> |
<holder>Intevation GmbH</holder> |
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</copyright> |
</copyright> |
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|
<revhistory> |
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|
<!-- comment this first revision out when releasing a real version --> |
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<revision> |
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|
<revnumber>1.0pre1 CVS $Id$</revnumber> |
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|
<date>$Date$</date> |
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|
<revremark>Under development.</revremark> |
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|
</revision> |
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|
<revision> |
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|
<revnumber>1.0pre1</revnumber> |
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|
<date>08-Aug-2003</date> |
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|
<revremark>Corresponds to Thuban development release 0.8.1</revremark> |
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|
</revision> |
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|
</revhistory> |
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|
|
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</bookinfo> |
</bookinfo> |
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|
|
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<chapter><title>Introduction</title> |
<chapter><title>Introduction</title> |
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|
|
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<section><title>Adding and Removing Layers</title> |
<section><title>Adding and Removing Layers</title> |
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<para> |
<para> |
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There are two types of layers that can be added to a map: shape layers |
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 |
and image layers. Shape layers are stored in Shapefile format, a |
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standard file format for storing geographic objects. These |
widely used file format for storing geographic objects. These |
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files have the extension ``.shp''. Associated with |
files have the extension ``.shp''. Associated with |
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the shape file is a database file which stores attributes for |
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, |
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. |
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 |
For example, if there is a shape file named roads.shp there must |
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also be a file roads.dbf. |
also be a file roads.dbf. |
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<guimenu>Map</guimenu> |
<guimenu>Map</guimenu> |
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<guimenuitem>Add Layer</guimenuitem> |
<guimenuitem>Add Layer</guimenuitem> |
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</menuchoice>. |
</menuchoice>. |
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Thuban will load all files with the same base name, so it doesn't |
Initially, only the ``.shp'' files are shown which is enough for the |
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matter if the shape file or database file is selected. |
selection. However, if you switch to display all files and select one |
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|
of the associated files (e.g. ``.dbf''), Thuban will recognize the base |
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|
name and load the corresponding Shape file. |
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|
</para> |
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|
<para> |
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|
The file dialog for Shape files allows to select multiple files. |
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|
Use the shift-button together with the left mouse button to extend |
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|
the selection. |
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</para> |
</para> |
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|
|
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<para> |
<para> |
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</section> |
</section> |
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</chapter> |
</chapter> |
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|
|
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<chapter><title>Extensions</title> |
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<para> |
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|
Thuban is designed to be extensible. The term Extension is used as a |
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general term for anything that extends Thuban. |
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|
This chapter introduces into some oppportunities how to add and |
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handle extra functionality developed by your own or third parties. |
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</para> |
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|
|
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<section><title>Add personal extensions via thubanstart.py</title> |
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<para> |
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|
After Thuban has been started for the first time, a directory |
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.thuban is created within your home directory. |
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There you can add a file thubanstart.py which will be imported |
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by Thuban at start-up. It is recommended to add only import-statements |
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to this file to keep the actual code of extensions separate. |
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</para> |
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<para> |
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|
The modules to import must either be found though the environment |
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variable PYTHONPATH or directly be placed into the .thuban-directory. |
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</para> |
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<para> |
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As an example, copy the file examples/simple_extensions/hello_world.py |
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of the Thuban source code into the .thuban-directory of your home |
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directory. Now add add the statement import hello_world to the |
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file thubanstart.py and run Thuban. You will notice an additional |
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menu <menuchoice><guimenu>Extensions</guimenu></menuchoice> where |
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the new item for the Hello-World extension is placed - select it |
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to see the Hello-World message. |
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</para> |
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</section> |
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|
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<section><title>Writing simple extensions</title> |
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<para> |
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Writing an extension for Thuban basically means to |
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implement the extra functionality in Python with all of the |
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Thuban classes, methods and variables available. |
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</para> |
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<para> |
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All classes and their methods are documented in the source code |
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(see their doc-strings). Here is an example from |
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Thuban/Model/layer.py that describes some of the methods |
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of a Layer object: |
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</para> |
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<programlisting> |
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<![CDATA[ |
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class BaseLayer(TitledObject, Modifiable): |
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|
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"""Base class for the layers.""" |
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|
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def __init__(self, title, visible = True, projection = None): |
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"""Initialize the layer. |
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|
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title -- the title |
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visible -- boolean. If true the layer is visible. |
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""" |
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TitledObject.__init__(self, title) |
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Modifiable.__init__(self) |
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self.visible = visible |
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self.projection = projection |
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|
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def Visible(self): |
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"""Return true if layer is visible""" |
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return self.visible |
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|
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def SetVisible(self, visible): |
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"""Set the layer's visibility.""" |
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self.visible = visible |
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self.issue(LAYER_VISIBILITY_CHANGED, self) |
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|
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def HasClassification(self): |
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"""Determine if this layer support classifications.""" |
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... |
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]]> |
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</programlisting> |
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<para> |
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This example intends to give you an impression of the |
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source-code-level documentation. |
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You have to make yourself familiar with |
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the Python programming language to understand some special |
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code elements. |
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</para> |
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<section><title>hello_world.py</title> |
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<para> |
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Traditionally, the first example should welcome the world. |
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Most of the code handles the frame for integrating a menu |
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item into Thuban while the actual raising of a message |
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is done in a single line. |
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</para> |
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<programlisting> |
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<![CDATA[ |
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# Copyright (C) 2003 by Intevation GmbH |
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# Authors: |
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# Jan-Oliver Wagner <[email protected]> |
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# |
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# This program is free software under the GPL (>=v2) |
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# Read the file COPYING coming with Thuban for details. |
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|
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""" |
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Extend Thuban with a sample Hello World to demonstrate simple |
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extensions. |
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""" |
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|
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__version__ = '$Revision$' |
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|
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# use _() already now for all strings that may later be translated |
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from Thuban import _ |
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|
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# Thuban has named commands which can be registered in the central |
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# instance registry. |
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from Thuban.UI.command import registry, Command |
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|
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# The instance of the main menu of the Thuban application |
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# See Thuban/UI/menu.py for the API of the Menu class |
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from Thuban.UI.mainwindow import main_menu |
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|
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def hello_world_dialog(context): |
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"""Just raise a simple dialog to greet the world. |
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|
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context -- The Thuban context. |
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""" |
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context.mainwindow.RunMessageBox(_('Hello World'), _('Hello World!')) |
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|
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|
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# create a new command and register it |
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registry.Add(Command('hello_world', _('Hello World'), hello_world_dialog, |
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helptext = _('Welcome everyone on this planet'))) |
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|
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# find the extensions menu (create it anew if not found) |
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extensions_menu = main_menu.find_menu('extensions') |
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if extensions_menu is None: |
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extensions_menu = main_menu.InsertMenu('extensions', _('E&xtensions')) |
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|
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# finally bind the new command with an entry in the extensions menu |
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extensions_menu.InsertItem('hello_world') |
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]]> |
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</programlisting> |
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</section> |
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<section><title>Registering a Command</title> |
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<para> |
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Mainly, our new function has to be registered to the Thuban |
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framework in order to connect it to the menu. A registered |
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command can also be connected to e.g. a toolbar button. |
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</para> |
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<para> |
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The instances and classes for this are imported at the beginning. |
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Any code not inside a method or class is directly executed when |
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the source-code module is imported. Therefore, the second |
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part of this example consist of the plain statements to create a new |
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Command and to add it to the menu. |
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</para> |
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<para> |
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By convention, it looks for a menu registered as ``extensions'' to |
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insert the new command. If it does not exist yet, it gets created. |
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It is advisable to copy this code for any of your extensions. |
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</para> |
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</section> |
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<section><title>The Thuban context</title> |
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<para> |
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A registered command that is called, always receives the |
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Thuban context. This instance provides our method with |
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hook references to all important components of the Thuban |
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application. |
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</para> |
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<para> |
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|
In the example hello_world.py, our function uses the |
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mainwindow component which offers a method to raise a |
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message dialog. In total there are three hooks: |
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|
<itemizedlist> |
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|
<listitem> |
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<para>application: |
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This object is the instance of the Thuban Application class. |
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Except maybe for loading or savinf sessions, you will not |
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need this object for a simple extension. |
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See Thuban/UI/application.py for the API. |
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</para> |
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</listitem> |
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<listitem> |
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<para>session: |
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The instance of the current session. It manages the sessions' |
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map and tables. You can set and remove the map or tables. |
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In may also get the map object. However, you should know that |
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internally it is already prepared to handle many maps. |
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Therfore, currently you would always receive a list with exactlty |
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one element. In the future, if there are more than one map, |
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you will not know which one is the currently display one and |
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therefore you should use the mainwindow as hook to find |
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the currently displayed map. |
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See Thuban/Model/session.py for the API. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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mainwindow: The mainwindow object is central to manage various |
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GUI things such as the Legend sub-window. Most notably, |
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you get access to the canvas which is the window part where |
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the map is drawn. The canvas knows, which map it currently |
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draws and therefore you get the current map via |
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context.mainwindow.canvas.Map(). |
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See Thuban/UI/mainwindow.py for the API. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</para> |
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</section> |
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</section> |
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</chapter> |
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|
|
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<chapter><title>Trouble Shooting</title> |
<chapter><title>Trouble Shooting</title> |
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<para> |
<para> |
| 1437 |
Here are a few problems that users have encountered when first using Thuban. |
Here are a few problems that users have encountered when first using Thuban. |
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