Greetings, I want to shift the UL x, UL y of an image.
I am trying to find out what the *dx_dy + dy_dx* is. The code is: import gdal ### open dataset with update permission ds = gdal.Open('/data/coastal-2020.tif', gdal.GA_Update) ### get the geotransform as a tuple of 6 gt = ds.GetGeoTransform() ### unpack geotransform into variables x_tl = (-180.0000000) x_res = 0.000800000000000 *dx_dy* = y_tl = (90.0000000) *dy_dx* = y_res = -0.000800000000000 x_tl, x_res, *dx_dy*, y_tl, *dy_dx*, y_res = gt # compute shift of 1 pixel RIGHT in X direction shift_x = 1 * x_res # compute shift of 2 pixels UP in Y direction # y_res likely negative, because Y decreases with increasing Y index shift_y = -2 * y_res # make new geotransform gt_update = (x_tl + shift_x, x_res, dx_dy, y_tl + shift_y, dy_dx, y_res) >From gdalinfo: Size is 450000, 225000 Coordinate System is: GEOGCRS["WGS 84", DATUM["World Geodetic System 1984", ELLIPSOID["WGS 84",6378137,298.257223563, LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0, ANGLEUNIT["degree",0.0174532925199433]], CS[ellipsoidal,2], AXIS["geodetic latitude (Lat)",north, ORDER[1], ANGLEUNIT["degree",0.0174532925199433]], AXIS["geodetic longitude (Lon)",east, ORDER[2], ANGLEUNIT["degree",0.0174532925199433]], ID["EPSG",4326]] Data axis to CRS axis mapping: 2,1 Origin = (-180.000000000000000,90.000000000000000) Pixel Size = (0.000800000000000,-0.000800000000000) Image Structure Metadata: COMPRESSION=LZW INTERLEAVE=BAND PREDICTOR=3 Corner Coordinates: Upper Left (-180.0000000, 90.0000000) (180d 0' 0.00"W, 90d 0' 0.00"N) Lower Left (-180.0000000, -90.0000000) (180d 0' 0.00"W, 90d 0' 0.00"S) Upper Right ( 180.0000000, 90.0000000) (180d 0' 0.00"E, 90d 0' 0.00"N) Lower Right ( 180.0000000, -90.0000000) (180d 0' 0.00"E, 90d 0' 0.00"S) Center ( 0.0000000, 0.0000000) ( 0d 0' 0.01"E, 0d 0' 0.01"N) -- Regards, Clive Swan --
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