Nikos: > > > # so, here it goes... seems to run fine > > > i.landsat.toar band_prefix=landsat_postfire_east_sterea_ellas > > > method=uncorrected sensor=5 date=2007-09-05 solar_elevation=52.4986238 > > > product_date=2007-09-05 > > > > ... > > > > > r.info landsat_postfire_east_sterea_ellas.toar.6 -r > > > min=203.36601783578 > > > max=319.083636050686 > > > > > > No way the min value is true ( 203 K = -70.15 C -- irrational for > > > Greece - for the moment! -) > > > > > > The max value (319 K = 45.85 C) seems to fit for Greece but not for > > > September! Maybe for July/August. > > > > looking at the image/histogram again those min and max are outliers I > > guess. The main body of information starts at ~280 K (6.85 C) and stops > > at ~307 K (33.85 C). > > > > I am not sure how to explain the min < 270 K (those values lie mostly > > within water bodies), but the max > 310 K areas are burned surfaces (a > > few days old burn scars) which will explain the 45 C (at surface) in a > > September day in Greece. > > > > So, those values seem rational after all. > > And, of course, an even better look reveals that those mins are the clouds > :-) > > # acca > i.landsat.acca -5 -2 -s band_prefix=landsat_postfire_east_sterea_ellas.toar > output=landsat_postfire_east_sterea_ellas.toar.acca > > Pass one processing ... > PRELIMINARY SCENE ANALYSIS > Desert index: 0.975 > Snow cover : 0.001 % > Cloud cover : 12.856 % > Temperature of all clouds > Maximum: 299.82 K > Mean : 251.23 K > Minimum: 203.37 K > HISTOGRAM CLOUD SIGNATURE > Histogram classes: 100 > Mean temperature: 254.32 K > Standard deviation: 15.99 > Skewness: 3298.36 > 97.50 percentile: 292.86 K > 83.50 percentile: 276.87 K > Pass two processing ... > > > Finds clouds, shadows but includes too many irrelevant pixels -- bad result > here :-( > > # withous the "-s" > i.landsat.acca -5 -2 band_prefix=landsat_postfire_east_sterea_ellas.toar > output=landsat_postfire_east_sterea_ellas.toar.acca --o > > Superb! This detects clouds (not the shadows though) very precise I dare to > say :D > > # with "-f" > not sure about the real differences with the previous command. Look fine > though :-)
OK, there is some salt and pepper but this can be removed by some filtering. It can be considered acceptable (?). Maybe I should post a screenshot (...later I'll try out the NC landsat5 image as well). _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
