[gdal-dev] Re-projecting with valid geometry

[klo uo]

Thanks Even,that's great solution.

Now, although ST_IsValid() doesn't report any more problems, QGIS "Check
geometry validity" still finds issues on 3 features.

I also tried ArcMap's "Check Geometry" function, and it found 2 "self
intersections". Features reported by QGIS and ArcMap are different.

This is just terrible file to work on, that's why I didn't want to touch or
edit anything inside. And now this validity tools all report issues on
different features...


Cheers



On Sat, Sep 6, 2014 at 2:43 PM, Even Rouault <even.rouault at spatialys.com>
wrote:

> Hi,
>
> >
> > Interestingly table reprojected with ogr2ogr shows errors on different
> > features then errors generated by PostGIS's ST_Transform() function.
>
> This is a bit surprising. ogr2ogr applies reprojection on each point of
> source
> geometries. I would have expected ST_Transform() to do the same.
>
> >
> > I wonder if there are some steps I can take before re-projecting or
> > afterward, that will produce valid transformation, without need of
> > correcting erroneous geometries by hand after re-projecting data?
>
> Not sure if this qualified of a by hand correction, but you may want to try
> ST_MakeValid() after ST_Transform() :
> http://postgis.org/docs/ST_MakeValid.html
>
> Even
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
>
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