[gdal-dev] Motion: adopt RFC 64: Triangle, Polyhedral surface and TIN

Even Rouault even.rouault at spatialys.com
Wed Dec 14 07:19:51 PST 2016


On mercredi 14 d├ęcembre 2016 10:05:46 CET Daniel Morissette wrote:
> +0 as I'm wondering if there could be a better way to handle this, i.e.
> it's not clear to me how useful it is to read/write those new geometry
> types without maintaining the (topological?) relationships between the
> objects. I am no expert with that type of data structures so my concerns
> may be completely invalid too and I have no alternative to offer, hence
> my +0.

The Simple Feature model clearly doesn't maintain topological relationships. Topological 
consistency must be checked in a later stage with a IsValid() call for example (this also holds 
true for already handled geometry types). And if you look at some drivers that implement 
TIN currenlty like PostGIS or GML, they are based on the Simple Feature model as well. Only 
shapefile/filegdb has something a bit stronger with shared nodes.

I think that support for topological geometries would be a completely different concept to 
be added in OGR. Would require management of nodes, edges and faces, and conversions 
between simple feature geometries and topogeometries. I had some preliminary discussions 
about that with an interested party in the past but they didn't go further.

In the current state of things, the TIN support should be hopefully good enough for 
conversions between PostGIS, GML, DXF and shapefile/filegdb.

Even

> 
> Daniel
> 
> On 2016-12-13 1:13 PM, Even Rouault wrote:
> > On vendredi 9 d├ęcembre 2016 12:10:25 CET Even Rouault wrote:
> >> Hi,
> >> 
> >> 
> >> 
> >> There have been some good remarks, one regarding integration with GEOS
> > 
> > that
> > 
> >> I've taken into account in the implementation, another one regarding the
> >> 
> >> possibility to get indexed TIN that I think can be later added if needed.
> >> 
> >> 
> >> 
> >> So I move to adopt RFC 64: Triangle, Polyhedral surface and TIN
> >> 
> >> 
> >> 
> >> https://trac.osgeo.org/gdal/wiki/rfc64_triangle_polyhedralsurface_tin
> >> 
> >> 
> >> 
> >> Starting with my +1,
> > 
> > Friendly remainder that this motion is under vote.
> > 
> > 
> > 
> > Even
> > 
> > 
> > 
> > --
> > 
> > Spatialys - Geospatial professional services
> > 
> > http://www.spatialys.com
> > 
> > 
> > 
> > _______________________________________________
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> > gdal-dev at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/gdal-dev


-- 
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