[mapserver-users] Re: Projection Question

[Frank Warmerdam]

"Kieran J. Ames" wrote:
> 
> Thanks, Frank, for your help. The Mapserver version I'm using at this
> time (can't get to it right now) is able to project the tif images I
> have. The new data will be stand-alone and not try to combine the
> Massachusetts tifs with the New York ones.

Kieran, 

OK, you must be using a 3.5ish version out of CVS if you have raster
resampling available (ie. mapresample.c) 
 
> Once, I found a listing that told me UTM 1927 was refered to as
> "clrk66". I can't seem to find that reference page again. I also found
> out that the Massachusetts data I have is Massachusetts State Plane
> 1983, (Mainland - meters) and I can't figure out how to declare that in
> the "proj=" portion.
> Can someone make some kind of code-decode table available for the valid
> values in "proj=" and "ellps="?
> TIA for any guidance or referals on this.

If you have PROJ fully installed the proj program has various option 
reporting commandline switches. 

"proj -lp" will list projections (+proj items)
"proj -le" will list known ellipsoids (+ellps items)
"proj -ld" will list known datums (+datum items)

For NAD 1983 it is generally sufficient for you to change your 
+ellps=clrk66 setting to +ellps=GRS80; however, with modern PROJ.4
releases you can also say +datum=NAD27 or +datum=NAD83 instead of the
+ellps settings.  The +datum settings imply +ellps settings. 

Best regards,

---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent