---------- Message transmis ---------- Sujet : Re: [gdal-dev] Alpha band masking Date : mardi 17 novembre 2015, 19:08:06 De : MUTLU OZDOGAN <ozdo...@wisc.edu> À : Even Rouault <even.roua...@spatialys.com>
Dear Even, It turns out that the problem was on my end! I was clipping the input image to corner coordinates that was outside of the input image and hence the 0 values. Thank you so much for you help. Mutlu.. On Nov 17, 2015, at 10:50 AM, Even Rouault <even.roua...@spatialys.com<mailto:even.roua...@spatialys.com>> wrote: Le mardi 17 novembre 2015 10:19:59, Mutlu Ozdogan a écrit : Yes I have removed the xml file sorry I forgot to include that Try also adding "-co alpha=no -overwrite" to the gdalwarp command line, although it shouldn't have any influence on the pixel values at that stage. Sent from my iPhone On Nov 17, 2015, at 3:04 AM, Even Rouault <even.roua...@spatialys.com<mailto:even.roua...@spatialys.com>> wrote: Le mardi 17 novembre 2015 04:08:41, MUTLU OZDOGAN a écrit : Dear Even, The result of the gdalinfo -mm command is this: Driver: GTiff/GeoTIFF Files: pr026029_5m.tif pr026029_5m.tfw Size is 35921, 41035 Coordinate System is: PROJCS["NAD83(HARN) / Wisconsin Transverse Mercator", GEOGCS["NAD83(HARN)", DATUM["NAD83_High_Accuracy_Reference_Network", SPHEROID["GRS 1980",6378137,298.2572221010002, AUTHORITY["EPSG","7019"]], AUTHORITY["EPSG","6152"]], PRIMEM["Greenwich",0], UNIT["degree",0.0174532925199433]], PROJECTION["Transverse_Mercator"], PARAMETER["latitude_of_origin",0], PARAMETER["central_meridian",-90], PARAMETER["scale_factor",0.9996], PARAMETER["false_easting",520000], PARAMETER["false_northing",-4480000], UNIT["metre",1, AUTHORITY["EPSG","9001"]]] Origin = (296789.742753763101064,562520.115095380693674) Pixel Size = (5.000000000000000,-5.000000000000000) Metadata: AREA_OR_POINT=Area Image Structure Metadata: INTERLEAVE=PIXEL Corner Coordinates: Upper Left ( 296789.743, 562520.115) ( 92d51'25.45"W, 45d30' 1.70"N) Lower Left ( 296789.743, 357345.115) ( 92d46' 5.00"W, 43d39'20.14"N) Upper Right ( 476394.743, 562520.115) ( 90d33'30.53"W, 45d32' 5.47"N) Lower Right ( 476394.743, 357345.115) ( 90d32'27.79"W, 43d41'16.23"N) Center ( 386592.243, 459932.615) ( 91d40'51.66"W, 44d36' 1.34"N) Band 1 Block=35921x1 Type=Byte, ColorInterp=Red Computed Min/Max=0.000,255.000 Mask Flags: PER_DATASET ALPHA Band 2 Block=35921x1 Type=Byte, ColorInterp=Green Computed Min/Max=0.000,255.000 Mask Flags: PER_DATASET ALPHA Band 3 Block=35921x1 Type=Byte, ColorInterp=Blue Computed Min/Max=0.000,255.000 Mask Flags: PER_DATASET ALPHA Band 4 Block=35921x1 Type=Byte, ColorInterp=Alpha Computed Min/Max=0.000,255.000 the exact commands I used are: gdal_translate pr026029_5m.tif tmp.tif -co alpha=no --> Did you remove tmp.tif.aux.xml as I mentionned before ? Note: given the use of gdalwarp you make, you could also just use gdal_translate -projwin instead (caution: the order of arguments is not the same since -projwin expect upper_left_x upper_left_y lower_right_x lower_right_y) then gdalwarp -te 422861.999 225313.018 489606.999 308903.018 -tr 5 5 tmp.tif out.tif The results of the out.tif is the problematic output as all the bands are zeros as in: Driver: GTiff/GeoTIFF Files: out.tif Size is 13349, 16718 Coordinate System is: PROJCS["NAD83(HARN) / Wisconsin Transverse Mercator", GEOGCS["NAD83(HARN)", DATUM["NAD83_High_Accuracy_Reference_Network", SPHEROID["GRS 1980",6378137,298.2572221010002, AUTHORITY["EPSG","7019"]], AUTHORITY["EPSG","6152"]], PRIMEM["Greenwich",0], UNIT["degree",0.0174532925199433]], PROJECTION["Transverse_Mercator"], PARAMETER["latitude_of_origin",0], PARAMETER["central_meridian",-90], PARAMETER["scale_factor",0.9996], PARAMETER["false_easting",520000], PARAMETER["false_northing",-4480000], UNIT["metre",1, AUTHORITY["EPSG","9001"]]] Origin = (422861.999000000010710,308903.017999999981839) Pixel Size = (5.000000000000000,-5.000000000000000) Metadata: AREA_OR_POINT=Area Image Structure Metadata: INTERLEAVE=PIXEL Corner Coordinates: Upper Left ( 422861.999, 308903.018) ( 91d11'47.57"W, 43d14'48.02"N) Lower Left ( 422861.999, 225313.018) ( 91d10'55.54"W, 42d29'38.70"N) Upper Right ( 489606.999, 308903.018) ( 90d22'27.90"W, 43d15' 8.35"N) Lower Right ( 489606.999, 225313.018) ( 90d22'11.62"W, 42d29'58.50"N) Center ( 456234.499, 267108.018) ( 90d46'50.60"W, 42d52'26.06"N) Band 1 Block=13349x1 Type=Byte, ColorInterp=Red Computed Min/Max=0.000,0.000 Mask Flags: PER_DATASET ALPHA Band 2 Block=13349x1 Type=Byte, ColorInterp=Green Computed Min/Max=0.000,0.000 Mask Flags: PER_DATASET ALPHA Band 3 Block=13349x1 Type=Byte, ColorInterp=Blue Computed Min/Max=0.000,0.000 Mask Flags: PER_DATASET ALPHA Band 4 Block=13349x1 Type=Byte, ColorInterp=Alpha Computed Min/Max=0.000,0.000 Thank you so much. Mutlu.. On Nov 16, 2015, at 3:21 AM, Even Rouault <even.roua...@spatialys.com<mailto:even.roua...@spatialys.com><mailto:even.roua...@spatialys.com>> wrote: Le samedi 14 novembre 2015 22:26:48, Mutlu Ozdogan a écrit : Dear Evan Thank you so much for the input. I actually tried exactly those steps and unfortunately I still get 0s in the output file. Thank you again Could you post the result of "gdalinfo -mm your_input_file.tif" and the exact GDAL commands you use ? Mutlu Sent from my iPhone On Nov 14, 2015, at 1:00 PM, Even Rouault <even.roua...@spatialys.com<mailto:even.roua...@spatialys.com><mailto:even.roua...@spatialys.com>> wrote: Le samedi 14 novembre 2015 19:49:02, ozdo...@wisc.edu<mailto:ozdo...@wisc.edu><mailto:ozdo...@wisc.edu> a écrit : Dear All I have a 4-band air photo image in which the 4th band is the NIR band but it has also been designated as an alpha band. It is the geotiff format. For some reason whenever I reproject this file (using gdalwarp) or resize it (using gdal_translate) all four bands of the resulting files have zero values. It is as if the alpha band is being used to mask all band values. Any help reprojecting or windowing this large file without making while retaining all 4 band values would be much appreciated. Thank you Mutlu, The issue is probably indeed the NIR band being recognized as an alpha band. You can remove the alpha interpretation with : gdal_translate in.tif tmp.tif -co alpha=no rm tmp.tif.aux.xml (or del tmp.tif.aux.xml on Windows) The removal of tmp.tif.aux.xml is important otherwise the alpha interpretation would be kept in this XML file And then you can gdalwarp this tmp.file with the arguments you need : gdalwarp tmp.tif ... Even -- Spatialys - Geospatial professional services http://www.spatialys.com -- Mutlu Ozdogan, Ph.D. Associate Professor Department of Forest and Wildlife Ecology & Nelson Institute for Environmental Studies t: (608) 262-0873 e: ozdo...@wisc.edu<mailto:ozdo...@wisc.edu> -- Spatialys - Geospatial professional services http://www.spatialys.com -- Mutlu Ozdogan, Ph.D. Associate Professor Department of Forest and Wildlife Ecology & Nelson Institute for Environmental Studies t: (608) 262-0873 e: ozdo...@wisc.edu<mailto:ozdo...@wisc.edu> ------------------------------------------------------- -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
