[Gdal-dev] California/CASIL's NAD27 DRGs

Tugrul Galatali tugrul at galatali.com
Fri Jul 9 13:19:22 EDT 2004

	I've found that in reprojecting the original NAD27 DRGs from CASIL
using gdalwarp to the local UTM zone, there are significant errors in
the registration of the resulting DRG. The source projection is outlined
on this page:


	Other programs like Global Mapper (somewhat unsuitable for batch
conversion) don't have any issue with these DRGs, and I can't find any
reference to this issue with gdal online. There are new NAD83 DRGs CASIL
just released that gdalwarp handles fine, but I'd like to avoid
redownloading the significant number of DRGs currently in use.

	Tugrul Galatali

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