[Proj] Albers reprojection anomoly?

Frank Warmerdam fwarmerdam at gmail.com
Wed Jun 29 14:10:44 EDT 2005

Gerald, or others,

In bug report:

a user reports that albers reprojection seems to not match what
he expects.  Based on his test datasets, I get:

input (+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 
          +x_0=0 +y_0=0 +ellps=clrk66 +units=m +no_defs):

  581715E, 1070148N

output (+proj=utm +zone=16 +datum=NAD27):
  239958E, 3602624N

output (expected for UTM 16 NAD27):
  239958E, 3602624N

As you can see the PROJ.4 translation seems to match well in
X but not in Y.  The user reports the expected information based
on reprojection with Global Mapper and ArcGIS.  

Can anyone comment on whether these values are in a region 
of reasonably validity for the UTM and Albers projection code?
Can anyone provide external verification one way or the other for
these albers to UTM conversions? 

Feel free to look into the bug report for details. 

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

More information about the Proj mailing list