[gdal-dev] gdal2tiles tile origin differences

[Matt Briggs]

Hi,
 
 I am getting different X and Y values for tiles from gdal2tiles.py when in a PC
 (OSGeo4W - GDAL 1.9.2) environment and Linux (GDAL
 1.10.1).  It seems to me that the newer 1.10.2 x's and y's are wrong (not respecting the specified origin). 

 Is this a bug, which result is correct, and how do I get them to
 behave the same?
  

===

Details:
 I've created a sample tileset on a PC in windows using the
 tools from GDAL 1.9.2 in OSGeo4W for a map in projection
 NZTM2000 (EPSG:2193).  The resulting tiles are
 generated as-per my expectations, and the origin from which
 the tiles are numbered is the origin of the projection
 (+lat_0=0 +lon_0=173).
 
 Having perfected this with a small map area, I switched to a
 cloud server running linux and gdal1.10.1.  The process
 appears to run successfully - tiles are generated, BUT the
 tile x and y numbers are different.
 
 After much stuffing around, I've realised that the x and y
 values used match those used for the same geographic area
 when using the default EPSG:4326.  
 
 During troubleshooting I have run the gdal2tiles on the same
 single map sheet with the same command line options in both
 environments, manually specifying the SRS in case the
 definitions differ, and got two different results. 
 I've also tested it using the built-in projection -s
 EPSG:2193.
 
 python gdal2tiles.py test.tif -s '+proj=tmerc +lat_0=0
 +lon_0=173 +k=0.9996 +x_0=1600000 +y_0=10000000 +ellps=GRS80
 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs' -z 5-10
 
 
 PC / Windows / Cygwin:
 mbriggs at forestero
 /d/OSGeo4W/maps_past $ ls test/11/
 1116/  1117/  1118/
 mbriggs at forestero
 /d/OSGeo4W/maps_past $ ls test/11/1116
 1303.png*  1304.png*
 mbriggs at forestero
 /d/OSGeo4W/maps_past $ 
 
 Linux:
 mbriggs at dev:~$ ls
 test/11
 2022  2023  2024  2025
 mbriggs at dev:~$ ls
 test/11/2022
 767.png  768.png  769.png
 mbriggs at dev:~$ 
 
 
 
 mbriggs at dev:~$ gdalinfo
 test.tif
 Driver: GTiff/GeoTIFF
 Files: test.tif
 Size is 4193, 2861
 Coordinate System is:
 PROJCS["unnamed",
     GEOGCS["GRS 1980(IUGG, 1980)",
         DATUM["unknown",
            
 SPHEROID["GRS80",6378137,298.257222101]],
         PRIMEM["Greenwich",0],
        
 UNIT["degree",0.0174532925199433]],
     PROJECTION["Transverse_Mercator"],
     PARAMETER["latitude_of_origin",0],
     PARAMETER["central_meridian",173],
     PARAMETER["scale_factor",0.9996],
     PARAMETER["false_easting",1600000],
     PARAMETER["false_northing",10000000],
     UNIT["metre",1,
         AUTHORITY["EPSG","9001"]]]
 Origin = (1810357.092181787360460,5488467.918922254815698)
 Pixel Size = (10.000000000000000,-10.000000000000000)
 Metadata:
   AREA_OR_POINT=Area
 Image Structure Metadata:
   INTERLEAVE=PIXEL
 Corner Coordinates:
 Upper Left  ( 1810357.092, 5488467.919)
 (175d29'27.21"E, 40d43'40.29"S)
 Lower Left  ( 1810357.092, 5459857.919) (175d30'
 2.02"E, 40d59' 7.25"S)
 Upper Right ( 1852287.092, 5488467.919) (175d59'12.51"E,
 40d42'57.90"S)
 Lower Right ( 1852287.092, 5459857.919) (175d59'54.22"E,
 40d58'24.47"S)
 Center      ( 1831322.092, 5474162.919)
 (175d44'39.06"E, 40d51' 3.45"S)
 Band 1 Block=4193x1 Type=Byte, ColorInterp=Red
   Mask Flags: PER_DATASET ALPHA 
 Band 2 Block=4193x1 Type=Byte, ColorInterp=Green
   Mask Flags: PER_DATASET ALPHA 
 Band 3 Block=4193x1 Type=Byte, ColorInterp=Blue
   Mask Flags: PER_DATASET ALPHA 
 Band 4 Block=4193x1 Type=Byte, ColorInterp=Alpha
 mbriggs at dev:~$ 
 
 
 
 Cheers,
 
 Matt