[gdal-dev] 4 point, projective warping

[Jeffrey Warren]

Hi, all - I need 4-point (GCP) projective warping (
http://docs.bentley.com/en/I-RASB/irasbhelp171.html) for my very basic
rubbersheeting app at http://cartagen.org/maps (getting full-res TMS output
working). These are for aerial photographs, not scanned images.

After banging my head against a wall for a while I'm doing it in ImageMagick
then gdal_translate then gdalwarp to get a geotiff. This is a bit
inefficient. Is there just no major need for a projective warp in gdalwarp,
or has nobody ever asked?

ImageMagick refers to it as a perspective distort and it is sadly
computationally more demanding, but does not compromise GCP positioning to
find a fit given 4 corners, as does the polynomial warping. Unless I'm
missing something.

Suggestions, or am I pretty much on track?
Jeff
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