> > The way I see it, there are two different ways to model Google Mercator: > 1. As a WGS84 datum/ellipsoid with a custom Mercator-based projection > which uses only the semi-major axis, as seems to be currently done in > EPSG: http://epsg-registry.org/export.htm?wkt=urn:ogc:def:crs:EPSG::3857 > 2. As the Google spheroid with Mercator 1SP and no transformation when > going to WGS 84. > > I don't think #1 is currently an option given the list of coordinate > transformation codes available in the GeoTIFF specification.
Right, there's no such coordinate transformation for GeoTIFF > > For #2, I would think/hope that if you specified the identity > 7-parameter transformation in the GeoTIFF header, ArcGIS would properly > reproject the image: Hum, this will not work I'm afraid. See my response to Dmitry's to see why +towgs84=0,0,0,0,0,0,0 is not appropriate. (Plus the fact that the +towgs84 in geotiff is probably not very widely supported.) > http://trac.osgeo.org/geotiff/ticket/26 > > André > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
