[Qgis-developer] [Qgis-user] Using/visualizing 3D data (Z values)

[Nathan Woodrow]

Very handy.  Is there any issues with exposing the Z values from QGIS?
 If it's there why not let people get to it.

- Nathan

On Wed, Sep 26, 2012 at 9:42 PM, Etienne Tourigny
<etourigny.dev at gmail.com> wrote:
> Thanks for the info.
>
> I was able to use shapely pretty easily, by passing the wkb from qgis
> to shapely via shapely.wkb.loads(wkb)
>
> This removed the need for actual file parsing, which qgis seem to do
> well (apart from the z-level values, which it reads but does not
> report),
>
> here is the relevant python code:
>
> from shapely.wkb import loads
> feat = QgsFeature()
> provider = layer.dataProvider()
> provider.select(provider.attributeIndexes())
> if provider.nextFeature(feat):
>   lines = loads(feat.geometry().asWkb())
>   if len(lines) == 1:
>     coords = lines[0].coords
>     (x,y,z[i]) = coords[i]
>
> cheers
> Etienne
>
> On Wed, Sep 26, 2012 at 3:26 AM, gene <martin.laloux at gmail.com> wrote:
>> Hello, In Python:
>> - For shapefiles, , I use the pyshp ( pyshp: Python Shapefile Library/
>> <http://code.google.com/p/pyshp/>  ) module of Joel Lawhead to read or write
>> 3D shapefiles:
>> (see  CreateElevationValues  : How to work with elevation (a.k.a. z) values.
>> <http://code.google.com/p/pyshp/wiki/CreateElevationValues>
>>>>>import shapefile
>>>>>r = shapefile.Reader("MyPolyZ")
>>>>>r.shapes()[0].points
>> [[-89.0, 33.0], [-90.0, 31.0], [-91.0, 30.0]]
>>>>>r.shapes()[0].z
>> [12, 11, 12]
>>
>> I use it without problem in the Python console  to process the results with
>> Shapely, Numpy or Grass.script
>>
>> - For kml files, it is relatively easy to parse files with standard modules
>> like Elementtree,  or with more specialized modules (
>> http://pypi.python.org/pypi?%3Aaction=search&term=kml&submit=search
>> <http://pypi.python.org/pypi?%3Aaction=search&term=kml&submit=search>  )
>>
>> I also use this approach in the Python console
>>
>>
>>
>> --
>> View this message in context: http://osgeo-org.1560.n6.nabble.com/Re-Qgis-user-Using-visualizing-3D-data-Z-values-tp5004272p5004487.html
>> Sent from the Quantum GIS - Developer mailing list archive at Nabble.com.
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