[GRASS-user] OpenFileGDB input error

Markus Metz markus.metz.giswork at gmail.com
Thu Sep 28 14:37:43 PDT 2017


On Thu, Sep 28, 2017 at 10:45 PM, Even Rouault <even.rouault at spatialys.com>
wrote:
>
[...]
>
> Ah, and related with that, starting with GDAL 2.2, you can also get new
geometry types, TRIANGLE, TIN and POLYHEDRALSURFACE.
>
> https://trac.osgeo.org/gdal/wiki/rfc64_triangle_polyhedralsurface_tin
>
> TIN can typically be found in some shapefiles and FileGDB.
POLYHEDRALSURFACE from some GML.
>
> To test easily, you can create a simple csv:
>
> id,WKT
> 1,"TRIANGLE ((0 0,0 1,1 1,0 0))"
> 2,"TIN (((0 0,0 1,1 1,0 0)))"
> 3,"POLYHEDRALSURFACE (((0 0,0 1,1 1,0 0)))"
>
> If you don't want to directly deal with those beasts in their native
form, you can force them to more standard types with:
> wkbTriangle : OGR_G_ForceTo( , wkbPolygon)
> wkbTIN / wkbPolyhedralSurface: OGR_G_ForceTo( , wkbMultiPolygon)

I tested with v.in.ogr, and OGR_G_GetLinearGeometry() does not convert
these beasts into a linear geometry.

Testing around a bit, the difference between OGR_G_GetLinearGeometry() and
OGR_G_ForceTo() is very useful. I would prefer to leave the decision if
these beasts can be safely converted to a linear form with
OGR_G_GetLinearGeometry() to the GDAL/OGR developers. They (have to, I
guess) spend a lot of time thinking about these geometry types coming from
OpenGIS Simple Feature specifications and currently 84 OGR drivers.

Markus M
>
> Even
>
>
>
> --
>
> Spatialys - Geospatial professional services
>
> http://www.spatialys.com
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