On Tue, Oct 18, 2016 at 12:24 PM, Stefan Sylla <[email protected]> wrote: > I have two Lansat 8 scenes from the same path/row and I try to perform > topographic correction with i.topo.corr. I have converted all images to > reflectance (DOS1) using i.landsat.toar. After that I tried to correct > topography using i.topo.corr. > > It seems to work fine with the 1st scene, but I get strange results with the > 2nd scene: > > Range of Scene 1 (Band 5) before i.topo.corr: min = 0.133723349810153 max > = 0.906354180100938 > Range of Scene 1 (Band 5) after i.topo.corr: min = 0.133760732072622 max = > 0.907846862031268 > Seems fine. > > Range of Scene 2 (Band 5) before i.topo.corr: min = 0 max = > 0.832036359894079 > Range of Scene 2 (Band 5) after i.topo.corr: min = -17160.1716925017 max = > 1438.29470705194 > > Don't understand why the value-range in scene 2 completely changes after > i.topo.corr.
I assume that both scenes overlap like 100%? Is it a rugged terrain? And: which method did you use? Note that the cosine method saturates when the slope is > 40° if I recall correctly. Markus _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
