I would also be interested in the answer to this question. Currently I export PostGIS data to shapefiles and use ogr2ogr to transform, if a grid shift is required. Perhaps the solution to this problem could be documented on the ST_Transform() page in the PostGIS manual?
Cheers, Francis 2010/6/9 Luís de Sousa <luis.a.de.so...@gmail.com> > Hello everyone, > > I'm trying to convert a series of spatial features from one SRS to > another within PostGIS. Both are local systems for continental > Portugal, for which a set of grid definition files have been made > available by the University of Oporto. I downloaded these grid files > and copied them into /usr/share/proj and /usr/local/share/proj. That > was enough to get proj to start using them. > > The problem is, when invoking the same transformation from PostGis I'm > getting errors in the range of tenths, sometimes hundreds, of metres. > It seems like PostGis is failing to use the grid files. In attachment > goes a log demonstrating the same transformation having different > results with proj and PostGis. > > What am I missing? Is there any extra configuration needed for PostGis > to use the grid files? > > Thank you, > > Luís > > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users > >
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