I have a geoTIFF with orthorectified aerial imagery in .sid format that does not project correctly in QGIS. The file originally did not have a .prj file, but projection information is stored in the file metadata, listed as "NAD_1927_Washington_North"

The file opens up and projects fine in ArcMap 10.4 (it lines up fine with other aerials, rasters, and vector data), but I don't have regular access to ArcMap. I tried exporting a .prj file for the projection from ArcMap with it correctly aligned, but that doesn't make a difference when I open it in QGIS.

My project is in EPSG:102748- Washington StatePlane North NAD 83 US Feet I have on the fly projection turned on. I have several different layer in different projections (e.g. UTM zone 10N, WGS 84) that all project fine, but I can't make this aerial line up.

I tried opening the raster in a clean workspace, then adding other data, but this doesn't seem to solve the problem.

I tried assigning a number of different projections, but couldn't find anything that worked. In EPSG: 32148, NAD83/Washington North, I can make it line up about 150 km east of the "correct" location, but can't do better without georeferencing the image from scratch.

I have intermittent access to ArcMap, so if there is something I can do to reproject the file there, it would be fine, but need to be able to use the layer in QGIS.

  • 1
    You can reproject the file but not as a SID, unless you have the MrSID cartridge. If you don't have enough access to ArcMap you can use gdal warp -s_srs EPSG:32048 -t_srs EPSG:102748 and output as JPEG or GeoTIFF with compression to keep the file small... depending on the size of your input and your workstation specs be prepared for it to run overnight or even a few days to project the whole raster. You could try define projection in ArcCatalog which should write the projection to an AUX file which QGIS may read if it's ignoring the PRJ file. – Michael Stimson Jun 13 '17 at 23:35

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