I want to generate a .vrt in epsg:3857 from a series of raster tiles in epsg:4326, and am trying to do so in one step using gdalbuildvrt with the -a_srs flag:
gdalbuildvrt -a_srs epsg:3857 ortho_3857.vrt ortho-*.tifThe projection is changed to 3857 as desired, however the corner coordinates, center and pixel sizes are incorrect (they are still in 4326, with the geographic extents of the corner coords messed up):
Driver: VRT/Virtual RasterFiles: ortho_3857.vrt /Users/jeremyeastwood/Desktop/debug/ortho-0-0.tif /Users/jeremyeastwood/Desktop/debug/ortho-0-1.tif /Users/jeremyeastwood/Desktop/debug/ortho-1-0.tif /Users/jeremyeastwood/Desktop/debug/ortho-1-1.tifSize is 9191, 7284Coordinate System is
ROJCS["WGS 84 / Pseudo-Mercator", GEOGCS["WGS 84", DATUM["WGS_1984", SPHEROID["WGS 84",6378137,298.257223563, AUTHORITY["EPSG","7030"]], AUTHORITY["EPSG","6326"]], PRIMEM["Greenwich",0, AUTHORITY["EPSG","8901"]], UNIT["degree",0.0174532925199433, AUTHORITY["EPSG","9122"]], AUTHORITY["EPSG","4326"]], PROJECTION["Mercator_1SP"], PARAMETER["central_meridian",0], PARAMETER["scale_factor",1], PARAMETER["false_easting",0], PARAMETER["false_northing",0], UNIT["metre",1, AUTHORITY["EPSG","9001"]], AXIS["X",EAST], AXIS["Y",NORTH], EXTENSION["PROJ4","+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs"], AUTHORITY["EPSG","3857"]]Origin = (-122.318962274868440,37.873466153295041)Pixel Size = (0.000000446142119,-0.000000446142119)Corner Coordinates:Upper Left (-122.3189623, 37.8734662) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Lower Left (-122.3189623, 37.8702165) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Upper Right (-122.3148618, 37.8734662) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Lower Right (-122.3148618, 37.8702165) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Center (-122.3169120, 37.8718413) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Band 1 Block=128x128 Type=Byte, ColorInterp=Red NoData Value=0Band 2 Block=128x128 Type=Byte, ColorInterp=Green NoData Value=0Band 3 Block=128x128 Type=Byte, ColorInterp=Blue NoData Value=0Band 4 Block=128x128 Type=Byte, ColorInterp=Alpha NoData Value=0 I can achieve the desired result by generating the vrt in the native projection then warping the result to 3857 with gdalwarp afterwards, but then I need to keep both .vrts about for future operations as the warped vrt references the native one, which references the original geotiffs, which is pretty messy.
Any suggestions on correct usage of the -a_srs flag in gdalbuildvrt (or a better understanding of its limitations), or how to generate a single warped vrt in a different projection from the raw geotiffs would be greatly appreciated.
Thanks.
أكثر...
gdalbuildvrt -a_srs epsg:3857 ortho_3857.vrt ortho-*.tifThe projection is changed to 3857 as desired, however the corner coordinates, center and pixel sizes are incorrect (they are still in 4326, with the geographic extents of the corner coords messed up):
Driver: VRT/Virtual RasterFiles: ortho_3857.vrt /Users/jeremyeastwood/Desktop/debug/ortho-0-0.tif /Users/jeremyeastwood/Desktop/debug/ortho-0-1.tif /Users/jeremyeastwood/Desktop/debug/ortho-1-0.tif /Users/jeremyeastwood/Desktop/debug/ortho-1-1.tifSize is 9191, 7284Coordinate System is
ROJCS["WGS 84 / Pseudo-Mercator", GEOGCS["WGS 84", DATUM["WGS_1984", SPHEROID["WGS 84",6378137,298.257223563, AUTHORITY["EPSG","7030"]], AUTHORITY["EPSG","6326"]], PRIMEM["Greenwich",0, AUTHORITY["EPSG","8901"]], UNIT["degree",0.0174532925199433, AUTHORITY["EPSG","9122"]], AUTHORITY["EPSG","4326"]], PROJECTION["Mercator_1SP"], PARAMETER["central_meridian",0], PARAMETER["scale_factor",1], PARAMETER["false_easting",0], PARAMETER["false_northing",0], UNIT["metre",1, AUTHORITY["EPSG","9001"]], AXIS["X",EAST], AXIS["Y",NORTH], EXTENSION["PROJ4","+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs"], AUTHORITY["EPSG","3857"]]Origin = (-122.318962274868440,37.873466153295041)Pixel Size = (0.000000446142119,-0.000000446142119)Corner Coordinates:Upper Left (-122.3189623, 37.8734662) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Lower Left (-122.3189623, 37.8702165) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Upper Right (-122.3148618, 37.8734662) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Lower Right (-122.3148618, 37.8702165) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Center (-122.3169120, 37.8718413) ( 0d 0' 3.96"W, 0d 0' 1.22"N)Band 1 Block=128x128 Type=Byte, ColorInterp=Red NoData Value=0Band 2 Block=128x128 Type=Byte, ColorInterp=Green NoData Value=0Band 3 Block=128x128 Type=Byte, ColorInterp=Blue NoData Value=0Band 4 Block=128x128 Type=Byte, ColorInterp=Alpha NoData Value=0 I can achieve the desired result by generating the vrt in the native projection then warping the result to 3857 with gdalwarp afterwards, but then I need to keep both .vrts about for future operations as the warped vrt references the native one, which references the original geotiffs, which is pretty messy.Any suggestions on correct usage of the -a_srs flag in gdalbuildvrt (or a better understanding of its limitations), or how to generate a single warped vrt in a different projection from the raw geotiffs would be greatly appreciated.
Thanks.
أكثر...