Bug report #813

Upsidedown (and rotated?) Rasters Not Supported

Added by Frank Warmerdam - over 16 years ago. Updated over 16 years ago.

Assignee:Frank Warmerdam -
Affected QGIS version: Regression?:No
Operating System:Debian Easy fix?:No
Pull Request or Patch supplied: Resolution:fixed
Crashes QGIS or corrupts data: Copied to github as #:10872


Upside rasters (that is the top is further south than the bottom) do not appear to be supported by the qgsrasterlayer code. If one is opened (as the only object) an empty extent is established for the map. I'm guessing this is because the min/max values in the layer extent are backwards.

Driver: ISIS3/USGS Astrogeology ISIS cube (Version 3)
Files: r0200357_10m_Jul20_o_i3_detatched.lbl
Size is 317, 559
Coordinate System is:
PROJCS["Equirectangular Mars",
Origin = (-4766.964843750000000,-872623.625000000000000)
Pixel Size = (10.102499961853027,10.102499961853027)
Corner Coordinates:
Upper Left  (   -4766.965, -872623.625) (175d35'13.52"W,  0d 0'53.02"S)
Lower Left  (   -4766.965, -866976.328) (175d35'13.52"W,  0d 0'52.68"S)
Upper Right (   -1564.472, -872623.625) (175d35'13.32"W,  0d 0'53.02"S)
Lower Right (   -1564.472, -866976.328) (175d35'13.32"W,  0d 0'52.68"S)
Center      (   -3165.719, -869799.976) (175d35'13.42"W,  0d 0'52.85"S)
Band 1 Block=317x1 Type=Byte, [[ColorInterp]]=Undefined
  [[NoData]] Value=0

A reduced resolution analog to the above is being attached as a tiff file.

sample.tif - upside mars image. (47.8 KB) Frank Warmerdam -, 2007-11-16 01:00 PM


#1 Updated by Frank Warmerdam - over 16 years ago

  • Status changed from Open to In Progress

In the raster tranparency branch I have made changes () that will place rotated/sheared/upsidedown images in the right portion of the map, but without the correct orientation. Because this is a fairly serious failure still, an interactive warning is issued to the user.

This lets folks see these images, but the failure to orient them right means they won't overlay other layers properly - still quite a serious bug. So on that basis I'm leaving this bug open in the hopes that at some point we will rework the raster layer sufficient to display non-northup images properly. This will require substantial work.

#2 Updated by Frank Warmerdam - over 16 years ago

Actually, as I think about it, another alternative used by some other software packages (ie. Cadcorp SIS) is to create a GDAL "warped VRT" in memory that will take care of resampling on the fly within GDAL.

#3 Updated by Frank Warmerdam - over 16 years ago

  • Resolution set to fixed
  • Status changed from In Progress to Closed

I have applied which rips out the changes from and replaces it with used of a "gdal warped vrt". This will render rotated, upside down and even "gcp controlled" images in the proper place. There is an outstanding issue of recognising nodata areas that may need action but that isn't the point of this particular bug report so I'm closing.

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