corrected WMSFactory example
This commit is contained in:
Artem Pavlenko
parent
50416422e0
commit
7d57b4d957
1 changed files with 149 additions and 149 deletions
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@ -1,149 +1,149 @@
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# $Id$
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Mapnik OGC Server
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-----------------
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Introduction
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------------
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Mapnik provides a server package to allow the publishing of maps
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through the open and standard WMS interface published by the Open Geospatial
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Consortium (OGC). It is in implemented in Python, around the core C++
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library.
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Features/Caveats
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----------------
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- WMS 1.1.1 and 1.3.0
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- CGI/FastCGI
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- GetCapabilities and GetMap support only (NO GetFeatureInfo)
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- JPEG/PNG output
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- XML/INIMAGE/BLANK error handling
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- No real layer metadata support yet
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- No re-projection support
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- Needs to be able to write to tempfile.gettempdir() (most likely "/tmp")
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Dependencies
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------------
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Please properly install the following before proceeding further:
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- jonpy (http://jonpy.sourceforge.net/)
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- lxml (http://codespeak.net/lxml/)
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- PIL (http://www.pythonware.com/products/pil)
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- PROJ.4 (http://proj.maptools.org/)
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Installation
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------------
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- Make sure you compile or re-compile Mapnik after installing PROJ.4, if this
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was not done already. Mapnik includes a Python API to the PROJ.4 library
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used by the ogcserver. The PROJ_INCLUDES and PROJ_LIBS parameters can
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be passed to mapnik's scons build script to help with this.
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You can test the availability of the PROJ.4 bindings by trying:
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$ python
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Python 2.3.4 (#1, Feb 22 2005, 04:09:37)
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[GCC 3.4.3 20041212 (Red Hat 3.4.3-9.EL4)] on linux2
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Type "help", "copyright", "credits" or "license" for more information.
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>>> from mapnik import Projection
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registered datasource : raster
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registered datasource : shape
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registered datasource : postgis
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>>>
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- The executable "ogcserver" in utils/ogcserver will work for both CGI and
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FastCGI operations. Where to place it will depend on your server's
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configuration and is beyond this documentation. For information on FastCGI
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go to http://www.fastcgi.com/.
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Configuring the server
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----------------------
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- You will need to edit the ogcserver executable for now. It is a simple
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Python text script.
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1) Edit the path to the interpreter in the first line.
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2) Edit the path to the config file if you don't like the default.
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- Copy the sample configuration "ogcserver.conf" file in utils/ogcserver to
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the location you specified in the previous step.
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- Edit the configuration file to your liking, the comments within the file will
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help you further. Be sure to at the very minimum edit the "module"
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parameter, the server will not work without you setting it properly first.
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Defining layers and styles for use by the ogcserver
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---------------------------------------------------
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The ogcserver obviously needs layers to publish. For now, with Mapnik, this
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can only be done by writing code. In this case, a Python script will need to be
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written to describe the layers and respective styles. For information on the Python
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API, look in demo/python, or in docs/epydocs.
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The server needs a python module, with code that looks like this:
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from mapnik.ogcserver.WMS import BaseWMSFactory
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class WMSFactory(BaseWMSFactory):
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def __init(self):
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BaseWMSFactory.__init__(self)
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sty = Style()
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...
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self.register_style('stylename', sty)
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lyr = Layer(name='layername', title='Highways', abstract='Highways')
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...
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lyr.styles.append('stylename')
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self.register_layer(lyr)
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self.finalize()
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The rules for writing this class are:
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- It MUST be called 'WMSFactory'.
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- It MUST sub-class mapnik.ogcserver.WMS.BaseWMSFactory.
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- The __init__ MUST call the base class'.
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- Layers MUST be named with the 'name' parameter to the constructor.
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- style and layer names are meant for machine readability, not human. Keep
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them short and simple, without spaces or special characters.
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- For human readable info, pass title='' and abstract='' parameters to the
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Layer() call.
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- The layers must have at least one style associated with them (a default).
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- No Map() object is used or needed here.
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- Be sure to call self.finalize() once you've registered everything! This will
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validate everything and let you know if there's problems.
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- Be sure to associate a default style with the layer. In the future, there
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will be a mechanism to assign other non-default styles to a layer, to support
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named styles through the STYLES= parameter.
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To Do
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-----
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- Named style support.
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- Improve configuration to allow for full server metadata.
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- Investigate moving to cElementTree from lxml.
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- Add some internal "caching" for performance improvements.
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- Support GetFeatureInfo (Requires core changes).
|
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- Switch to using C/C++ libs for image generation, instead of PIL (also
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requires core changes). PIL requirement will remain for INIMAGE/BLANK
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error handling.
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Conclusion
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----------
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This is the very first implementation of a WMS for Mapnik. Although inital
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testing seems to suggest it works well, there may be bugs, and it lacks some
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useful features. Comments, contributions, and requests for help should all be
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directed to the Mapnik mailing list.
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Enjoy!
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J.F.
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# $Id$
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Mapnik OGC Server
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-----------------
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|
||||
|
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Introduction
|
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------------
|
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|
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Mapnik provides a server package to allow the publishing of maps
|
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through the open and standard WMS interface published by the Open Geospatial
|
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Consortium (OGC). It is in implemented in Python, around the core C++
|
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library.
|
||||
|
||||
|
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Features/Caveats
|
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----------------
|
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|
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- WMS 1.1.1 and 1.3.0
|
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- CGI/FastCGI
|
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- GetCapabilities and GetMap support only (NO GetFeatureInfo)
|
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- JPEG/PNG output
|
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- XML/INIMAGE/BLANK error handling
|
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- No real layer metadata support yet
|
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- No re-projection support
|
||||
- Needs to be able to write to tempfile.gettempdir() (most likely "/tmp")
|
||||
|
||||
|
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Dependencies
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------------
|
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|
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Please properly install the following before proceeding further:
|
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|
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- jonpy (http://jonpy.sourceforge.net/)
|
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- lxml (http://codespeak.net/lxml/)
|
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- PIL (http://www.pythonware.com/products/pil)
|
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- PROJ.4 (http://proj.maptools.org/)
|
||||
|
||||
|
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Installation
|
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------------
|
||||
|
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- Make sure you compile or re-compile Mapnik after installing PROJ.4, if this
|
||||
was not done already. Mapnik includes a Python API to the PROJ.4 library
|
||||
used by the ogcserver. The PROJ_INCLUDES and PROJ_LIBS parameters can
|
||||
be passed to mapnik's scons build script to help with this.
|
||||
|
||||
You can test the availability of the PROJ.4 bindings by trying:
|
||||
|
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$ python
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Python 2.3.4 (#1, Feb 22 2005, 04:09:37)
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[GCC 3.4.3 20041212 (Red Hat 3.4.3-9.EL4)] on linux2
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Type "help", "copyright", "credits" or "license" for more information.
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>>> from mapnik import Projection
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registered datasource : raster
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registered datasource : shape
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registered datasource : postgis
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>>>
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- The executable "ogcserver" in utils/ogcserver will work for both CGI and
|
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FastCGI operations. Where to place it will depend on your server's
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configuration and is beyond this documentation. For information on FastCGI
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go to http://www.fastcgi.com/.
|
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Configuring the server
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----------------------
|
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|
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- You will need to edit the ogcserver executable for now. It is a simple
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Python text script.
|
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|
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1) Edit the path to the interpreter in the first line.
|
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2) Edit the path to the config file if you don't like the default.
|
||||
|
||||
- Copy the sample configuration "ogcserver.conf" file in utils/ogcserver to
|
||||
the location you specified in the previous step.
|
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|
||||
- Edit the configuration file to your liking, the comments within the file will
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help you further. Be sure to at the very minimum edit the "module"
|
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parameter, the server will not work without you setting it properly first.
|
||||
|
||||
|
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Defining layers and styles for use by the ogcserver
|
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---------------------------------------------------
|
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|
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The ogcserver obviously needs layers to publish. For now, with Mapnik, this
|
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can only be done by writing code. In this case, a Python script will need to be
|
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written to describe the layers and respective styles. For information on the Python
|
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API, look in demo/python, or in docs/epydocs.
|
||||
|
||||
The server needs a python module, with code that looks like this:
|
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from mapnik.ogcserver.WMS import BaseWMSFactory
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class WMSFactory(BaseWMSFactory):
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def __init__(self):
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BaseWMSFactory.__init__(self)
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sty = Style()
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...
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self.register_style('stylename', sty)
|
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|
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lyr = Layer(name='layername', title='Highways', abstract='Highways')
|
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...
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lyr.styles.append('stylename')
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self.register_layer(lyr)
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self.finalize()
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|
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The rules for writing this class are:
|
||||
|
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- It MUST be called 'WMSFactory'.
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- It MUST sub-class mapnik.ogcserver.WMS.BaseWMSFactory.
|
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- The __init__ MUST call the base class'.
|
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- Layers MUST be named with the 'name' parameter to the constructor.
|
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- style and layer names are meant for machine readability, not human. Keep
|
||||
them short and simple, without spaces or special characters.
|
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- For human readable info, pass title='' and abstract='' parameters to the
|
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Layer() call.
|
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- The layers must have at least one style associated with them (a default).
|
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- No Map() object is used or needed here.
|
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- Be sure to call self.finalize() once you've registered everything! This will
|
||||
validate everything and let you know if there's problems.
|
||||
- Be sure to associate a default style with the layer. In the future, there
|
||||
will be a mechanism to assign other non-default styles to a layer, to support
|
||||
named styles through the STYLES= parameter.
|
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|
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To Do
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-----
|
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|
||||
- Named style support.
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- Improve configuration to allow for full server metadata.
|
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- Investigate moving to cElementTree from lxml.
|
||||
- Add some internal "caching" for performance improvements.
|
||||
- Support GetFeatureInfo (Requires core changes).
|
||||
- Switch to using C/C++ libs for image generation, instead of PIL (also
|
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requires core changes). PIL requirement will remain for INIMAGE/BLANK
|
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error handling.
|
||||
|
||||
|
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Conclusion
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----------
|
||||
|
||||
This is the very first implementation of a WMS for Mapnik. Although inital
|
||||
testing seems to suggest it works well, there may be bugs, and it lacks some
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||||
useful features. Comments, contributions, and requests for help should all be
|
||||
directed to the Mapnik mailing list.
|
||||
|
||||
Enjoy!
|
||||
J.F.
|
||||
|
|
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|||
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