RE [gdal-dev] Translating between UTM and Geographic

Steve.Toutant at Steve.Toutant at
Wed Sep 23 13:21:50 EDT 2009

The problem might not be in your code but in the WKT projection 
information (sSpRefParams).

Steve Toutant, M. Sc.
Analyste en géomatique
Secteur environnement
Direction des risques biologiques, environnementaux et occupationnels
Institut national de santé publique du Québec
945, avenue Wolfe
Québec, Qc G1V 5B3 
Tél.: (418) 650-5115 #5281
Fax.: (418) 654-3144
steve.toutant at

"Henneke, Amanda M" <amanda.m.henneke at> 
Envoyé par : gdal-dev-bounces at
23/09/2009 11:16 AM

"gdal-dev at" <gdal-dev at>

[gdal-dev] Translating between UTM and Geographic

Hello all-

I'm trying to figure out how to reproject some points from a UTM 
projection to Geographic (WGS84) projection.  This works fine when I'm 
working in UTM Zone 12 with NAD83.  When I try the same code for Zone 11 
NAD27, I get a slight shift in the points (to the east) and an extremely 
slight shift up (to the north).

I've included the following code as it stands now, I've tried all sorts of 
things thinking that I need to somehow include more information for the 
new spatial reference (the destination SR), and so far I'm coming up 

Anyone have any ideas what I'm missing?

Where sSpRefParams is a string that contains the WKT projection 
information from a valid layer...

srOld = new OSGeo.OSR.SpatialReference(sSpRefParams);

srNew.SetGeogCS("Geographic Coordinate System", 
"Greenwich", 0.0, "degree", 0.0174532925199433);

ctTransform = new OSGeo.OSR.CoordinateTransformation(srOld, srNew);

Amanda M. Henneke
IG/DB Tools - TSS Capability Center
Boeing - St. Louis

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