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I am trying to get oblique tiles into a mosaic dataset. The tiling scheme works perfectly well for vertical and north imagery (using google tiling scheme) through the GDAL driver, however I am struggling to get 45 degree tiles in.

The tiles are indexed very similarly to google tiles (starting at top left) as per example below (East orientation):

enter image description here

The crux of the problem is the CRS as defined by the GDAL XML. This is what it looks like for vertical imagery:

<GDAL_WMS> <Service name="TMS"> <ServerUrl>http://example.com?x=${x}&amp;y=${y}&amp;z=${z}</ServerUrl> </Service> <DataWindow> <UpperLeftX>12523442.7125</UpperLeftX> <UpperLeftY>-1878516.40687</UpperLeftY> <LowerRightX>13149614.8481</LowerRightX> <LowerRightY>-2504688.5425</LowerRightY> <TileLevel>21</TileLevel> <SizeX>8388608</SizeX> <SizeY>8388608</SizeY> <TileX>1703936</TileX> <TileY>1146880</TileY> <YOrigin>top</YOrigin> </DataWindow> <Projection>PROJCS["WGS_1984_Web_Mercator_Auxiliary_Sphere",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433],AXIS["Lat",SOUTH],AXIS["Long",EAST]],PROJECTION["Mercator_Auxiliary_Sphere"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",0.0],PARAMETER["Standard_Parallel_1",0.0],PARAMETER["Auxiliary_Sphere_Type",0.0],UNIT["Meter",1.0],AUTHORITY["EPSG",3857]]</Projection> <BlockSizeX>256</BlockSizeX> <BlockSizeY>256</BlockSizeY> <BandsCount>3</BandsCount> <UnsafeSSL>true</UnsafeSSL> <MaxConnections>10</MaxConnections> </GDAL_WMS>

My theory is that I need to rotate the coordinate system so that, in the example of East orientation, Y axis gots towards East, and X axis goes towards South. After trying a few things I could not get it to work. The best candidate was an affine transform as described here https://gis.stackexchange.com/a/159134/52713, however that just resulted in an invalid dataset (using identity transform or no-op transform), showing up in ArcMap like so:

enter image description here

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Igor Zevaka
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  • how are the tiles oblique? Is it a rotated rectangular image or nodata filled. All images must be rectangular but can be rotated or filled... generating seamlines on a raster dataset might help. – Michael Stimson May 05 '16 at 23:44
  • The tiles are square. The are "oblique" because they were taken at an angle and then chopped up into tiles. Depending on the orientation, a different compass point is at the top edge of the tile as per the diagram in the question. – Igor Zevaka May 06 '16 at 00:24
  • Can you show what one tile looks like.. what format are they in? is there a world file to show the parameters? I suspect that your tiles contain all data but have rotation coefficients in their georeference.. In the old days we would Rectify these images which fills in the rest of the rectangle by adding nodata because ArcINFO couldn't display a rotated image. You should be able to Affine the extents using the world file https://en.wikipedia.org/wiki/World_file if you export to world tiff (gdal_translate with TFW=YES parameter). – Michael Stimson May 06 '16 at 00:33
  • Why not rotate them by -90 in batch using spatial analyst? – FelixIP May 06 '16 at 01:22
  • @FelixIP Rotating the tiles is not really feasible due to the scale and we want them to be in that orientation so that they can be displayed in a web client without the need to rotate them. – Igor Zevaka May 06 '16 at 03:40
  • @MichaelMiles-Stimson I don't have a world file. I can have a go hand crafting it, but it requires a projection, which I don't have, which is also the question that I am asking. – Igor Zevaka May 06 '16 at 03:44
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    Not really, if the tiles are georeferenced the coordinates are specified as a 6 parameter transformation (affine), spatial reference is something else entirely. It only becomes a problem of spatial reference if you've got the tiles (rectangular) in one spatial reference but want to see them in a different spatial reference, if that's the case create the boxes in the native spatial reference, densify and project the boxes. Try one and see what you get. – Michael Stimson May 06 '16 at 04:03
  • Now that you have experimented with doing this using GDAL and ArcMap, I think you should reduce the scope of your question to one, the other, or to some other GIS product to try and entice potential answerers to provide one. – PolyGeo Jun 25 '16 at 00:01

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