[gdal-dev] VRT and M-dimension - any example?

[Even Rouault]

Le mardi 10 mai 2016 14:38:01, Jukka Rahkonen a écrit :
> Hi,
> 
> Release notes https://trac.osgeo.org/gdal/wiki/Release/2.1.0-News announce
> that RFC 61: Support for measured geometries is implemented in VRT.
> However, this is not mentioned in http://www.gdal.org/drv_vrt.html. I
> would like to improve the documentation but before I can do that I need to
> understand how it works. Could somebody help a bit with making a valid VRT
> for
> 
> - CSV source
> - GeometryType>wkbPointZM</GeometryType>
> - GeometryField encoding="PointFromColumns"
> 
> Or are the PointFromColumn attributes simply x="x" y="y" z="z" m="m" ?

Ah good point, PointFromColumn has not been extended to support the m 
attribute. The support for M / ZM is just in passthrough mode :

pointzm.csv:
id,WKT
1,"POINT ZM (1 2 3 4)"

pointzm.vrt:
<OGRVRTDataSource>
  <OGRVRTLayer name="pointzm">
    <SrcDataSource relativeToVRT="1">pointzm.csv</SrcDataSource>
    <SrcLayer>pointzm</SrcLayer>
    <GeometryType>wkbPointZM</GeometryType>
  </OGRVRTLayer>
</OGRVRTDataSource>



> 
> -Jukka Rahkonen-
> 
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