Hi, I've been trying to convert a *.png file to geotiff and I have the necessary coordinates to do so. However I'm having problems trying to get the geotiff to display properly (it's flipped) and I need some advice!
The *.png details are: UL: 37.686398 23.744484 LL: 38.073174 21.922295 UR: 40.149170 24.165144 LR: 40.501301 22.346598 CEN: 39.0938495 23.0437195 Skew/rotation: -12.3321408987529 (anti-clockwise from North) After extensive searching on the web for solutions, this is how far I've got: Start by converting *.png to *.tif using ImageMagick: Get information on the *.tif with gdal: Driver: GTiff/GeoTIFF Files: image.tif Size is 1488, 2447 Coordinate System is `' Metadata: TIFFTAG_DOCUMENTNAME=image.tif TIFFTAG_RESOLUTIONUNIT=1 (unitless) TIFFTAG_XRESOLUTION=72 TIFFTAG_YRESOLUTION=72 Image Structure Metadata: COMPRESSION=DEFLATE INTERLEAVE=PIXEL Corner Coordinates: Upper Left ( 0.0, 0.0) Lower Left ( 0.0, 2447.0) Upper Right ( 1488.0, 0.0) Lower Right ( 1488.0, 2447.0) Center ( 744.0, 1223.5) Band 1 Block=1488x1 Type=Byte, ColorInterp=Red Band 2 Block=1488x1 Type=Byte, ColorInterp=Green Band 3 Block=1488x1 Type=Byte, ColorInterp=Blue Convert the *.tif to a geotif by using GCPs: Apply the projection, WGS84: The resulting image is: <http://osgeo-org.1560.x6.nabble.com/file/n5251005/image_init_geo.png> The image is in the correct orientation and coordinate location, but the image is upside down. I found a python script ( http://blog.perrygeo.net/2007/09/05/the-world-turned-right-side-up/ <http://blog.perrygeo.net/2007/09/05/the-world-turned-right-side-up/> ) that will flip the image to the correct view, but the orientation is now wrong: <http://osgeo-org.1560.x6.nabble.com/file/n5251005/image_geo.png> I’m new to python so I haven’t been able to work out if there is something in the python script that can be changed to resolve this problem. Initially I tried to manually create a world file ( https://en.wikipedia.org/wiki/World_file <https://en.wikipedia.org/wiki/World_file> ), but I just couldn’t get it to plot in the correct location, even with the rotation values set to zero: *.tfw contents: 0.001891736 0.0000000000 0.0000000000 -0.000916571 37.68734387 23.74494229 metadata.txt contents: Geotiff_Information: Version: 1 Key_Revision: 1.0 Tagged_Information: ModelTiepointTag (2,3): 0 0 0 37.686398 23.744484 0 ModelPixelScaleTag (1,3): 0.001891736 -0.000916571 0 End_Of_Tags. Keyed_Information: GTModelTypeGeoKey (Short,1): ModelTypeGeographic GTRasterTypeGeoKey (Short,1): RasterPixelIsArea GeographicTypeGeoKey (Short,1): GCS_WGS_84 End_Of_Keys. End_Of_Geotiff. GCS: 4326/WGS 84 Datum: 6326/World Geodetic System 1984 Ellipsoid: 7030/WGS 84 (6378137.00,6356752.31) Prime Meridian: 8901/Greenwich (0.000000/ 0d 0' 0.00"E) PROJ.4 Definition: +proj=latlong +ellps=WGS84 +to_meter=1.0000000000 Corner Coordinates: Upper Left (37.686398, 23.744484) Lower Left (38.073174, 21.922295) Upper Right (40.14917, 24.165144) Lower Right (40.501301, 22.346598) Center (39.0938495, 23.0437195) Does anyone have any ideas on how I can keep the image’s orientation correct while flipping it? -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Creating-geotiff-with-rotation-but-image-is-flipped-tp5251005.html Sent from the GDAL - Dev mailing list archive at Nabble.com. _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
