[PATCH] RPC_DEM functionality in GDALRPCTransform

[bishop]

Fixed in r24094

[bishop]

add support for DEM files

[Even Rouault]

I've made a few changes and commited them in r19864 and r19866. Test added in r19865.

The changes are :

• lazy opening of the DEM file the first time we need it and close it only when the transform is destroyed (address the point in your comment)
• caching of the inverse geotransform et coordinate transform
• replace OGR errors -> CPL errors
• test that dX, dY is in the extent of the dataset
• replace GDT_Int16 by GDT_Int32 as we use array of int and not array of short
• several fixes in the bDstToSrc == FALSE case that wasn't probably much tested (padfX[i] used instead of padfY[i] at line 736, poCT->Transform() was wrongly tested against OGRERR_xxx instead of TRUE/FALSE)

Please test and report if it still works for you.

[bishop]

Great work! I have tested it. The result is more accurate (in case of output image size) and the speed is march faster (about 5 times). The test data with RPC was taken from DigitalGlobe samples (​http://www.digitalglobe.com/index.php/70/Product+Samples) - QuickBird: Ortho Ready Standard Satellite Imagery And DEM file was taken from here ​http://www.gdem.aster.ersdac.or.jp/

[bishop]

I added cubic interpolation of elevation and config option (GDAL_RPCDEMINTERPOLATION) to choose between BILINEAR and CUBIC

[bishop]

dem interpolation patch