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

[Ed McNierney]

Tugrul -

Is your PROJ installation set up to include datum-shift support
(assuming you're trying to go to NAD83 UTM)?  Could you give us specific
information about a specific input file and the exact problems you see
with the corresponding output file?

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242 s 

-----Original Message-----
From: gdal-dev-bounces at xserve.flids.com
[mailto:gdal-dev-bounces at xserve.flids.com] On Behalf Of Tugrul Galatali
Sent: Friday, July 09, 2004 1:19 PM
To: gdal-dev at xserve.flids.com
Subject: [Gdal-dev] California/CASIL's NAD27 DRGs

	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:

http://casil.ucdavis.edu/casil/gis.ca.gov/drg/projection.html

	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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