raster projector

[Frank Warmerdam]

John Smith wrote:
> guys,
> trying to put a geotiff in- works but not right. here's what's happening:
> 
> i download the geotiff from national atlas. when i give no proj info 
> under LAYER it shows up but not where it should (nwis). so i copy MAP 
> proj to LAYER proj hoping for some on-the-fly magic- again it shows up 
> but nwis.
> 
> well i go over to proj_list 
> <http://www.remotesensing.org/geotiff/proj_list/> and look up the epsg 
> (EPSG?) code (9820) from metadata but it throws the 
> "msProcessProjection(): Projection library error. no options found in 
> 'init' file" error. then i try all epsg codes given by gdalinfo ;) but 
> same error. although when i try the MAP epsg code (4326) it shows up but 
> nwis.
>  
> so what's wrong here? think proj.exe geod.exe cs2cs.exe libgeotiff 
> listgeo'd help? now i don't think wld is needed because it's included 
> with the geotiff but i've tried with wld and no luck. i just hope i 
> don't have to rectify in arcmap. btw IMAGETYPE=png24 in case that matters.

John,

I don't believe there is an EPSG code corresponding to this coordinate
system:

PROJCS["TIFF 6.0, GeoTIFF Revision 1.0",
     GEOGCS["WGS 84",
         DATUM["WGS_1984",
             SPHEROID["WGS 84",6378137,298.2572235630016,
                 AUTHORITY["EPSG","7030"]],
             AUTHORITY["EPSG","6326"]],
         PRIMEM["Greenwich",0],
         UNIT["degree",0.0174532925199433],
         AUTHORITY["EPSG","4326"]],
     PROJECTION["Lambert_Azimuthal_Equal_Area"],
     PARAMETER["latitude_of_center",45],
     PARAMETER["longitude_of_center",-100],
     PARAMETER["false_easting",0],
     PARAMETER["false_northing",0],
     UNIT["metre",1,
         AUTHORITY["EPSG","9001"]]]

But the corresponding PROJECTION block to put in the LAYER definition
is:

  PROJECTION
   "+proj=laea +lat_0=45 +lon_0=-100 +x_0=0 +y_0=0 +datum=WGS84 +units=m"
  END

At one time you could also put:
  PROJECTION
   "AUTO"
  END

and MapServer would read it from the geotiff file, but I'm not sure if this
still works.

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    | President OSGeo, http://osgeo.org