Hi there,

Does anybody has ever tried to orthorectify an "Ortho Ready Standard" QuickBird image with .TIL files?

To whom might be interested, there is a couple of sample data on digitalglobe.com and you can always find DEM on USGS.COM.

Contrary to GDAL standards :) in most of those sample dataset the .RPB file are not directed associated to the Geotiff file. Like in

some_file_name.tif
some_file_name.rpb

That is usually the case when the scene covered is too big and the data provider decided to dived it on tiles.

The .TIL file describe the offsets in lines/pixel/X/Y of each of the tiles and the .RPB is related to the .TIL file. Like in:

some_file_t1.tif
some_file_t2.tif
some_file_t3.tif
some_file_name.til
some_file_name.rpb

Since GDAL does not support the .TIL file, what one needs to do is to use gdalbuildvrt to create a VRT to represent the same tilling as the .TIL file.

At that point it is still not ready to do orthorectification yet because gdalwarp doesn't seems to digest the combination .VRT .RPB.

some_file_name.vrt
some_file_name.rpb

But that is just a matter of converting the VRT to GTIFF and go ahead and run:

gdalwarp some_file_name.tif the_output_name.tif -rpc -to RPC_DEM=the_dem_file.tif -t_srs EPSG:32610

But after all that I can't see much more accuracy when overlaying a vector road map on top of the original non-orthorectified than over the orthorectified output. It is a little bit better in some places but worse in some others.

I found much better results with datasets without tilling. I mean, without .TIL files. Just one GTIFF and one .RPB

Has anybody had that same experience?

Do we have plans to support the .TIL file in GDAL?

Best regards,

Ivan










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