Jaak Laineste (Nutiteq <jaak <at> nutiteq.com> writes: > Isn't there really better solution than dual-transformation? The problem with this is that you need pick a > projection wisely, and there is no global projection what you can use without having big distortions > nearer to poles (in the case of Mercator for example. You need to use projection depending on particular > location, and even then you would have transformation errors. > > Root problem is that most JTS/GEOS, including buffer() implementations can do cartesian math only. Good > solution would be to implement buffer function from latitude/longitude directly, say > buffer(lat,lon,buffer_meters). Any takers?
I do not understand much about these things and I mainly wanted to demonstrate that what can be done in PostGIS is ofter possible to do without PostGIS by using GDAL and the SQLite/Spatialite dialect. I feel that first steps towards what Jaak wil have has been taken in PostGIS with the LWGEOM function ST_Project http://postgis.net/docs/manual-2.1/ST_Project.html The same function is also available in Spatialite 4.1 http://www.gaia-gis.it/gaia-sins/spatialite-sql-4.1.0.html and in GDAL through OGR SQLite dialect. What seems to be is missing is calculating the right azimuths for offsetting vertices and smuggling the code inside the buffer function. -Jukka Rahkonen- > > Jaak > _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
