Nikos: ... > Downloaded: > - extra: LT50160351988258XXX03 (includes visible clouds - maybe good for > testing?)
# import landsat bands in wgs84, utm, zone 17 # r.proj to nc_spm_08/landsat # set region g.region rast=lsat5_1988.1 -p projection: 99 (Lambert Conformal Conic) zone: 0 datum: nad83 ellipsoid: a=6378137 es=0.006694380022900787 north: 361770 south: 144750 west: 463950 east: 709530 nsres: 30 ewres: 30 rows: 7234 cols: 8186 cells: 59217524 # rgb colors for 742 i.landsat.rgb r=lsat5_1988.2 g=lsat5_1988.4 b=lsat5_1988.7 strength=96 d.rgb r=lsat5_1988.2 g=lsat5_1988.4 b=lsat5_1988.7 # obvious clouds # toar i.landsat.toar band_prefix=lsat5_1988 method=uncorrected sensor=5 product_date=1988-09-14 date=1988-09-14 solar_elevation=48.6773844 # acca i.landsat.acca -5f2 band_prefix=lsat5_1988.toar output=lsat5_1988.toar.acca # how many cats? r.info lsat5_1988.toar.acca -r min=6 max=9 # draw only "acca" cat=6 d.erase black d.rast lsat5_1988.toar.acca cat=6 -o In the "acca" result: - clouds are detected (cat=6), not that bad(ly) I suppose. Some filtering could push away the (rest of the) "noise". - obvious mis-detections (commission errors) found within - n=188310 s=168270 w=618870 e=636150 (bare ground? urban area? not sure about the confusing land cover/class here...) - n=219030 s=180510 w=646410 e=655740 (road) - in the borders due to the non-identical extent of all bands (!?) - categories 7 and 8 seem to be empty, category 9 looks very messy Could it be that non-cloudy acquisitions are mistreated by the algorithm? I can't clearly recognise clouds in the landsat scenes included in NC data set (both the 1987 and the 2000 scenes). Will (then) the algorithm work (only) with (very) cloudy data? Nikos _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
