[Gdal-dev] gdalwarp incorrect output origin

[Richard Greenwood]

Hello;

Gdalwarp appears to be a wonderful tool.  Thank you Frank, for yet another 
great contribution to the world of open source geo-spatial software. 
Unfortunately, I am having some difficulty with gdalwarp, and I am seeking 
help. Specifically, I do not seem to be getting the correct origin in the 
output file. I am trying to convert from utm nad83, zone 12 to wyoming 
state plane nad83 west u.s. survey feet. I am launching gdalwarp as follows:

gdalwarp
     -s_srs "+proj=utm +ellps=GRS80 +zone=12 +north +datum=NAD83 +units=m 
+no_defs"
     -t_srs "+proj=tmerc +ellps=GRS80 +units=ft +lon_0=-110.0833333333 
+lat_0=40.5 +x_0=800000 +y_0=100000 +k=0.9999375 +no_defs"
     -order 3
     44110a71.ecw
     nw.tif

For my input file, gdalinfo returns:

     gdalinfo 44110A71.ecw
     Driver: ECW/ERMapper Compressed Wavelets
     Size is 5680, 7562
     Coordinate System is `'
     Origin = (509637.500000,4886074.500000)
     Pixel Size = (1.000000,-1.000000)

And for the output file:

     gdalinfo nw.tif
     Driver: GTiff/GeoTIFF
     Size is 5764, 7625
     Coordinate System is:
     PROJCS["unnamed",
     GEOGCS["unnamed",
         DATUM["unknown",
             SPHEROID["unnamed",6378137,298.2572221010002]],
         PRIMEM["Greenwich",0],
         UNIT[,0.0174532925199433]],
     PROJECTION["Transverse_Mercator"],
     PARAMETER["latitude_of_origin",40.5],
     PARAMETER["central_meridian",-110.0833333333],
     PARAMETER["scale_factor",0.9999375],
     PARAMETER["false_easting",800000],
     PARAMETER["false_northing",100000],
     UNIT["unknown",1]]
     Origin = (590,671.522659,1,423,022.262198)

However, using corpscon to convert the origin point yields:

     ;SOFTWARE:  Corpscon for Windows 5.11.08
     ;Horizontal Datum:  State Plane, NAD83
     ;Horizontal Zone:   Wyoming West - 4904
     ;Horizontal Units:  U.S. Survey Feet
         2,415,615.01666, 1,651,102.28794

(I realize that simply converting the origin with corpscon is not going to 
provide exactly the same output origin as gdalwarp, I'm just using it to 
illustrate the general neighborhood that I am expecting).

The source and target srs definitions are ones that I have used 
successfully with mapserver.

Any suggestions?

Rich

Richard W. Greenwood, PLS
(307) 733-0203
Rich at GreenwoodMap.com
www.GreenwoodMap.com