<div class="gmail_quote">I sometimes get the error message "ERROR 1: latitude or longitude exceeded limits" when using gdalwarp with Quickbird, Worldview and Geoeye images using RPCs, both with and without a DEM. Sometimes I also get the error message "ERROR 1: Too many points (441 out of 441) failed to transform, unable to compute output bounds". Both errors suggest that the RPC transformations are not working, sometimes often enough for the process to completely fail and sometimes enough only to make the output extent really bogus.<br>
<br>Using the config option CHECK_WITH_INVERT_PROJ=TRUE does not help. Nor does setting the center long with the CENTER_LONG config option. Nor does using WGS84 as the target coordinate system. When I run gdalwarp with --debug on, I get up to 88,000 lines like these:<br>
<br>RPC: Iterations 10: Got: 153.057,-43.5705 Offset=-88416.5,407.11<br>RPC: Iterations 10: Got: 34.9369,156.643 Offset=-328767,-402.914<br>ERROR 1: latitude or longitude exceeded limits<br><br> I am a python coder, not a C++ guru, but looking through the underlying code it seems that even after the maximum 10 iterations the RPC inverse transform cannot get close to the correct pixel/line value (see the function RPCInverseTransformPoint). Any ideas what is wrong with these RPCs?<br>
<br>My images are almost entirely in polar regions (above 60 and below -60), but not near the poles themselves. Only about 5% of the images fail. I am running on both the 1.8 gdal build for OSGeo4w and also on a 1.9 linux build made by our Sys Admin. Both builds have the same error. The images will orthorectify correctly using ERDAS. I can provide debug output files and sample images if necessary.<br>
<br>Example syntax: gdalwarp --debug ON -t_srs EPSG:3031 -rpc -to "RPC_DEM=y:/dem/RAMPv2_osu91a200m.tif" QB02_05OCT222204548-M1BS-10100100049A4300.ntf QB02_10oct22_3031.tif<br><br>Thank you,<br>Claire<span class="HOEnZb"><font color="#888888"><br>
<br>-- <br>
Claire Porter<br>
Remote Sensing Scientist<br>
Polar Geospatial Center<br>University of Minnesota<br><br>
</font></span></div><br>