[Proj] (no subject)
Frank Warmerdam
warmerdam at pobox.com
Wed Jul 30 01:36:51 EDT 2008
usha regadi wrote:
> hello
>
> give me procedure to perform inv projection operation to convert
> the coordinates from x,y to (lambda, phi)
>
> regards
> usha
Usha,
I think you need to give more context to get a good answer. Do you want
to do it with commandline utilities? C API? Do you just want the math?
What projected coordinate system are you interested in? I'll assume
you mean projected easting,northing by x,y and longitude,latitude by
lambda,phi. If that is so, perhaps a commandline example for a particular
projection would be helpful.
proj -I +proj=utm +zone=11 +ellpse=WGS84 < in.dat > out.dat
in.dat might contain a value like:
400000 3730000
and then out.dat will be written as:
118d4'44.85"W 33d42'18.962"N
In the above command, the -I means inverse (ie. projected to geographic rather
than geographic to projected), and +proj=utm +zone=11 +ellps=WGS84 defines the
coordinate system.
Keep in mind, the quality of the answer you get does bear some relation to
the quality of the question.
Best regards,
--
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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
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