id summary reporter owner description type status priority milestone component version severity resolution keywords cc 7164 vrt multiresolution mosaic glitch mclausen warmerdam "we are trying to setup an aerial image multi resolution mosaic with vrt. These vrt files will be used afterwards for the visualization with mapserver 6.4. we would like to combine two raster datasets one with 10cm pixel size and one with 25cm pixel size in one vrt file. the aerial image data is in the same reference system. what we observe is, if you overlay the mixed resolution vrt (dop25_dop10_kombo.vrt) with the lower resolution vrt (dop25.vrt) or with the source dataset you can see an offset in the lower resolution parts of the image. you can use this link to visualize the offset [1]. The offset is not evenly distributed on the image and it depends on zoomlevel and image detail. The same effect is visible in gqis 2.14.8 and arcmap 10.4.1 using this vrt files directly. do you have any idea what is causing this effect and how we could get around it? you will find the data here [2] this is how we have created the vrt files and some metadata about the source images [3] thank you in advance for your help. marcel [1] https://s.geo.admin.ch/7719c8ee5e [2] https://data.geo.admin.ch/test/ltclm/testdata.tar.gz [3] {{{ $ echo 1126-33.tif DOP10_LV95_25861219_2015_1_15.tif | xargs gdalbuildvrt -resolution user -tr 0.1 0.1 -srcnodata ""0 0 0"" dop25_dop10_kombo.vrt $ gdalbuildvrt dop25.vrt 1126-33.tif $ gdalbuildvrt dop10.vrt DOP10_LV95_25861219_2015_1_15.tif $ gdalbuildvrt --version GDAL 2.3.0dev, released 2017/99/99 }}} source image information 10cm pixel size: {{{ $ gdalinfo DOP10_LV95_25861219_2015_1_15.tif Driver: GTiff/GeoTIFF Files: DOP10_LV95_25861219_2015_1_15.tif Size is 10000, 10000 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 = (2586000.000000000000000,1220000.000000000000000) Pixel Size = (0.100000000000000,-0.100000000000000) Metadata: AREA_OR_POINT=Area TIFFTAG_DATETIME=2014:01:07 13:45:26 TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch) TIFFTAG_SOFTWARE=Adobe Photoshop CS4 Windows TIFFTAG_XRESOLUTION=72 TIFFTAG_YRESOLUTION=72 Image Structure Metadata: INTERLEAVE=PIXEL Corner Coordinates: Upper Left ( 2586000.000, 1220000.000) ( 7d15'18.11""E, 47d 7'55.84""N) Lower Left ( 2586000.000, 1219000.000) ( 7d15'18.22""E, 47d 7'23.46""N) Upper Right ( 2587000.000, 1220000.000) ( 7d16' 5.57""E, 47d 7'55.92""N) Lower Right ( 2587000.000, 1219000.000) ( 7d16' 5.67""E, 47d 7'23.53""N) Center ( 2586500.000, 1219500.000) ( 7d15'41.89""E, 47d 7'39.69""N) Band 1 Block=10000x1 Type=Byte, ColorInterp=Red Band 2 Block=10000x1 Type=Byte, ColorInterp=Green Band 3 Block=10000x1 Type=Byte, ColorInterp=Blue }}} source image information 25cm pixel size {{{ $ gdalinfo 1126-33.tif Driver: GTiff/GeoTIFF Files: 1126-33.tif 1126-33.tif.ovr Size is 17500, 12000 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 = (2585000.000000000000000,1221000.000000000000000) Pixel Size = (0.250000000000000,-0.250000000000000) Metadata: AREA_OR_POINT=Area TIFFTAG_RESOLUTIONUNIT=3 (pixels/cm) TIFFTAG_XRESOLUTION=28.346458 TIFFTAG_YRESOLUTION=28.346458 Image Structure Metadata: COMPRESSION=YCbCr JPEG INTERLEAVE=PIXEL SOURCE_COLOR_SPACE=YCbCr Corner Coordinates: Upper Left ( 2585000.000, 1221000.000) ( 7d14'30.54""E, 47d 8'28.15""N) Lower Left ( 2585000.000, 1218000.000) ( 7d14'30.90""E, 47d 6'51.00""N) Upper Right ( 2589375.000, 1221000.000) ( 7d17'58.19""E, 47d 8'28.46""N) Lower Right ( 2589375.000, 1218000.000) ( 7d17'58.45""E, 47d 6'51.30""N) Center ( 2587187.500, 1219500.000) ( 7d16'14.52""E, 47d 7'39.74""N) Band 1 Block=256x256 Type=Byte, ColorInterp=Red Overviews: 8750x6000, 4375x3000, 2188x1500, 1094x750, 547x375, 274x188, 137x94 Band 2 Block=256x256 Type=Byte, ColorInterp=Green Overviews: 8750x6000, 4375x3000, 2188x1500, 1094x750, 547x375, 274x188, 137x94 Band 3 Block=256x256 Type=Byte, ColorInterp=Blue Overviews: 8750x6000, 4375x3000, 2188x1500, 1094x750, 547x375, 274x188, 137x94 }}} " defect closed normal default unspecified normal invalid