[Gdal-dev] gdal_translate with onearth png

[wsacul]

I'd like to take elevation data from the onearth server and convert it
to a geotiff.

Here's a server request:

http://onearth.jpl.nasa.gov/browse.cgi?wms_server=wms.cgi&layers=worldwind_dem&srs=EPSG:4326&width=1000&height=1000&bbox=-120,30,-90,60&format=image/png&styles=feet_short_int&zoom=

I save the image and attempt to process it with gdal_translate:

gdal_translate -of GTIFF -a_ullr -120 15 -90 45 test.png test.tif

(at this point, gdal 1.3.0 on gentoo complains "option -a_ullr
incomplete, or not recognized", but the same thing in cygwin with
1.3.0.0b1 processes the image fine)

gdal_translate has worked fine for me with making image geotiffs, but
now that I want to make an elevation geotiff what do I need to do?  Is
there a different tool I should be using?

Thanks,

lucasw