Hi, I'm using the otb::DEMHandler and the otb::InverseSensorModel, to convert ground geographic coordinates into image coordinates (radar images). I have a problem with the TransformPoint() method in a specific case (-> 1) and a question ( ->2).
(1) Using SRTM data, I set up DEM directory with OpenDEMDirectory() method and the Geoid with the OpenGeoidFile(). (In this case i used .hgt SRTM and the egm96 grid from the otb-data) : - When the geoid affectation line is commented out (only the DEM), no geoid is taken into account and everything seems to work fine... . At the end, the TransformPoint() of the InverseSensorModel returns relevant image coordinates and as a verification the GetHeightAboveMSL() and GetHeightAboveEllipsoid() return the same value (srtm value). - But when the demHandler->OpenGeoidFile(..) is uncommented (DEM+geoid), the TransformPoint() of the InverseSensorModel returns the initial ground geographic coordinates instead of image coordinates... However the geoid is correctly taken into account as the GetHeightAboveMSL and GetHeightAboveEllipsoid return 2 values with the expected offset (50m in my area) Do i do something wrong ? In both cases should TransformPoint return radar image coordinates, but maybe slightly different ? (2) Alternatively, i want to use my own Geotif DEM on the area. The OpenDEMDirectory() works well on my DEM (GetHeightAboveEllipsoid() gives me the correct "my" DEM value). In the documentation it is said that "OTB relies on OSSIM for elevation handling. [...] Note that OSSIM internal calls for sensor modelling use the height above ellipsoid". Can you confirm me that in that case I have to give the OpenDEMDirectory() my DEM expressed in Height above Ellipsoid in the EGM96 (or EGM2008) geoid vertical datum, so that the ground to image transformation is done correctly by OSSIM ? Regards, Sébastien -- -- Check the OTB FAQ at http://www.orfeo-toolbox.org/FAQ.html You received this message because you are subscribed to the Google Groups "otb-users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/otb-users?hl=en --- You received this message because you are subscribed to the Google Groups "otb-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
