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
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