Andreas, I assume you run a recent enough version of GDAL ?
As the image uses JPEG compression, one explanation would be that the transition betweeen data and nodata is not "clean" (which is a feature of JPEG compresssion). Therefore you would need to first translate your image to a uncompressed one (or one with a non -JPEG compression), and run nearblack - white on it so as to clean those edges. Even > Hi, > > I have Orthoimages where the boundaries aren't rectangular, but they > have corners and sometimes even diagonal edges. > > I noticed, that after creating pyramids/overview with gdaladdo, that I > get antialiasing/rendering artefacts that aren't present in the original > image at full resolution. See attached image that shows the problem. I > used a pink background to emphasize the problem. > > My nodata values are set to white (rgb 255,255,255) in the original > image. > > Here is the gdaladdo command that I used: > > gdaladdo -r cubic --config BIGTIFF_OVERVIEW YES --config > COMPRESS_OVERVIEW JPEG --config JPEG_QUALITY 85 --config > PHOTOMETRIC_OVERVIEW YCBCR --config INTERLEAVE_OVERVIEW PIXEL > dop2002_lv95.tif 2 4 8 16 32 64 128 256 512 1024 > > This is the output of gdalinfo on the original image: > > ----------------------- > > Driver: GTiff/GeoTIFF > Files: dop2002_lv95 - Kopie.tif > Size is 240000, 190000 > Coordinate System is: > PROJCS["CH1903+ / LV95", > GEOGCS["CH1903+", > DATUM["CH1903+", > SPHEROID["Bessel 1841",6377397.155,299.1528128, > AUTHORITY["EPSG","7004"]], > TOWGS84[674.374,15.056,405.346,0,0,0,0], > AUTHORITY["EPSG","6150"]], > PRIMEM["Greenwich",0, > AUTHORITY["EPSG","8901"]], > UNIT["degree",0.0174532925199433, > AUTHORITY["EPSG","9122"]], > AUTHORITY["EPSG","4150"]], > PROJECTION["Hotine_Oblique_Mercator_Azimuth_Center"], > PARAMETER["latitude_of_center",46.95240555555556], > PARAMETER["longitude_of_center",7.439583333333333], > PARAMETER["azimuth",90], > PARAMETER["rectified_grid_angle",90], > PARAMETER["scale_factor",1], > PARAMETER["false_easting",2600000], > PARAMETER["false_northing",1200000], > UNIT["metre",1, > AUTHORITY["EPSG","9001"]], > AXIS["Easting",EAST], > AXIS["Northing",NORTH], > AUTHORITY["EPSG","2056"]] > Origin = (672000.000000000000000,234000.000000000000000) > Pixel Size = (0.100000000000000,-0.100000000000000) > Metadata: > AREA_OR_POINT=Area > TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch) > TIFFTAG_XRESOLUTION=1 > TIFFTAG_YRESOLUTION=1 > Image Structure Metadata: > COMPRESSION=YCbCr JPEG > INTERLEAVE=PIXEL > SOURCE_COLOR_SPACE=YCbCr > Corner Coordinates: > Upper Left ( 672000.000, 234000.000) ( 13d51' 5.78"W, 35d55'48.10"N) > Lower Left ( 672000.000, 215000.000) ( 13d47'45.10"W, 35d46' 1.03"N) > Upper Right ( 696000.000, 234000.000) ( 13d35'53.15"W, 35d59'13.56"N) > Lower Right ( 696000.000, 215000.000) ( 13d32'34.61"W, 35d49'25.99"N) > Center ( 684000.000, 224500.000) ( 13d41'49.73"W, 35d52'37.44"N) > Band 1 Block=256x256 Type=Byte, ColorInterp=Red > NoData Value=255 > Band 2 Block=256x256 Type=Byte, ColorInterp=Green > NoData Value=255 > Band 3 Block=256x256 Type=Byte, ColorInterp=Blue > NoData Value=255 > > ---------------------------------------------------------------------------- > --- > > > Is there a way to get rid of these artefacts at the nodata borders? > > Thank you and greetings, > > Andreas -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
