[Tickets] Re: [Python Cartographic Library] #87: DiskFeatureStore: 3D Polygons not handled

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#87: DiskFeatureStore: 3D Polygons not handled
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  Reporter:  ludwig                   |       Owner:  seang
      Type:  defect                   |      Status:  new  
  Priority:  major                    |   Milestone:  0.11 
 Component:  Data Stores and Sources  |     Version:       
Resolution:                           |    Keywords:       
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Comment (by ludwig):

 This is definitely a 3D Shapefile issue. While 3D (or 2.5D) data cannot be
 seen on mapserver maps, I think at least the X and Y data should be
 available.

 The first bits for handling 3D shapes that are missing is the mapping in
 disk.py for the geometry type as reported by ogr. The GEOM_MAP does not
 have the mapping set out. Extending the GEOM_MAP with the other geometry
 types from ogr is easy.


 {{{
 GEOM_MAP = {
     1: 'Point',
     2: 'LineString',
     3: 'Polygon',
   ....

     }
 }}}


 On a mapping point of view I would think that is a mistake to duplicate
 the key values from ogr.py, the safer way of coding this would be to take
 the ogr values, such as


 {{{
 GEOM_MAP = {
     ogr.wkbPoint: 'Point',
     ogr.wkbLineString: 'LineString',
     .....
     ogr.wkbPoint25D: 'Point25D',
     ...

 }}}

 That not only makes it clearer where the values come from and that they
 should not be altered in PCL, and if the ogr lib would ever change them,
 PCL would not have to change.

 With this change, at least inspection of the features in 3D libs is
 possible in PCL.

 Rendering however fails with the following error:


 {{{
 File "/opt/python243/lib/python2.4/site-
 packages/cartography/engine/mapserver/rendering.py", line 235, in render
     lo.draw(mo, im)
   File "/opt/python243/lib/python2.4/site-packages/mapscript.py", line
 788, in draw
     def draw(*args): return _mapscript.layerObj_draw(*args)
 MapServerError: msDrawShape(): General error message. Only polygon shapes
 can be drawn using a POLYGON layer definition.

 }}}

 I think the first change suggested should be made, I am not sure what
 changes would be required to draw only X and Y data from a 3D shapefile
 and whether this would affect mapserver code or could be done in PCL.

-- 
Ticket URL: <http://trac.gispython.org/projects/PCL/ticket/87>
Python Cartographic Library <http://trac.gispython.org/projects/PCL/>
Python Cartographic Library