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

[Etienne Tourigny]

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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