Blake Willmarth wrote:
> Hi all, I'm new to geoprocessing and C in general.
>
> The Plan: Get coordinates from a shapefile and look up their values in a
> geotiff image. Both use datum GCS_NAD83, the tiff is projected in Albers
> Equal-Area Conic (both use ellipsoid GRS 1980).
>
> The problem is the coordinates are coming out in degrees and I need to
> project them to Albers meters in order to look up the tiles - it's
> simply(?) a matter of converting the units. Is there a way to do this in
> libgeotiff or do I have to use another library, such as PROJ.4?
Blake,
This is not a simple conversion of units. The transformation between
projected (albers meters) and geographic (lat/long degrees) is non-linear
and needs to be done using a projections library like PROJ.4. PROJ.4
should be fairly easily used in combination with libgeotiff and you can
see some example use in the bin/listgeo.c utility.
Best regards,
--
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