[Proj] Azimuthal Equidistant projection Northern Hemisphere centric

Andrew Williams awilliams at rapidmap.com.au
Tue Jan 31 23:32:57 EST 2006

Hi folks,
I'm using GDAL to try and warp an AEQD projected image to Latlong. 
This is the syntax
gdalwarp -s_srs "+proj=aeqd +lat_0=0 +long_0=134 +x_0=0 +y_0=0" -t_srs "+proj=latlong +datum=WGS84" input.tif output.tif
The issue is that the image is a Southern hemisphere Equatorial projection of Australia. The image is warping, but instead of "spreading" the Southern part of the image so that line of longitude no longer converge, it's spreading the Northern part of the image and making it worse.
It looks like the warp calculation is assuming a Northern aspect where the lines of longitude converge at the top of the image rather than the bottom of the image in a Southern aspect.
The reason for my enquiry here is to find out if I can (or need to) add some other parameter to the source definition to make GDAL sensitive to the fact that it's a Southern Hemisphere rather than Northern hemisphere projection.

More information about the Proj mailing list