At 11:56 AM 10/30/2002 -0500, you wrote:
I need to project a raster dataset from sphere/geodetic to an orthographic
projection. ER Mapper 6.3 seems to have problems making the conversion. I
get an error saying that the extents can not be determined or that there is
no ability to go from the geodetic data to an orthographic projection.  Does
anyone have a way to work around this? What intermediate projection might
work?
First, make sure your Geodetic image is properly projected (the reg coord
should be in decimal degrees, not D:M:S, and the coord type should be set
the EN.) Then make sure the Lat Long extents of your Geodetic image correspond
to the area defined for the orthographic projection (you don't say which one
you're trying to use). Most projections are built to cover a specific area,
the reprojection will fail if your input image extends outside that. (I've seen
people try to reproject a 30 deg wide area into a UTM zone, which would cause
the image to fold back around on itself, thus it fails.) That may
not be your problem, but it's something to consider. You may need to define
a new orthographic projection for your area.

Eric Augenstein
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Earthstar Geographics
5330 Carroll Canyon Road
Suite 206
San Diego, CA 92121 USA

Email: [EMAIL PROTECTED]
Web: www.es-geo.com
Tel: +1 858-455-9970
Fax: +1 858-455-9971
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