[Gdal-dev] SAR and shaded relief

[Charles Wivell]

Back in 1992 (yes, I'm that old...) when there were plans for an EOS SAR mission, my office mate and I put together an automated EOS-1/JERS-1 SAR ortho-correction system using a SAR shaded relief map as the reference.

Using the supplied position and Doppler information, we flew a math model of the SAR (solving the Doppler equation) over the DEM/Earth model and created a shaded relief map of what the SAR should have seen. Like always, SAR is the opposite of optical, meaning the brightness of the SAR return is proportional to sin(Z).  This image was then correlated to the actual SAR image and the differences were used to correct the position and attitude of the satellite. Using the corrected SAR model and the DEM/Earth model, the SAR image can then be ortho-corrected. It worked pretty good (see the April 1993 issue of PE&RS). But unfortunately, the EOS SAR idea was scrapped, so nothing ever came of our efforts. But it was a fun exercise.

Chuck

>>> "Ethan Alpert" <ealpert at digitalglobe.com> 12/13/05 12:59 PM >>>



Now the question of how to make closed vector contours from the shaded
relief output. The reason I ask this is how I think demis.nl does it.

http://www.demis.nl/home/pages/wms/demiswms.htm 

Converting to a vector contour set and overlaying partially transparent
layers on top creates quite an aesthetic look with the added advantage
when you zoom in it doesn't get grainy.

I've use NCAR Graphics to contour the output of the shaded relief cpp
sent out yesterday (using gdal_translate to convert to netCDF) and it
looks great the problem is it's not a shapefile and can only be viewed
in NCARG graphics. Anyone know of any filled contour utilities that
return polygons which I might be able to translate back into the proper
projection?

-e