Bug report #16045

QGIS Referencer: Tranformed Failed

Added by David Brown over 6 years ago. Updated over 6 years ago.

Category:C++ plugins/Georeferencer
Affected QGIS version:2.18.2 Regression?:No
Operating System:OSX Easy fix?:No
Pull Request or Patch supplied:No Resolution:not reproducable
Crashes QGIS or corrupts data:No Copied to github as #:23960


I'm using a new install of QGIS 2.18.2 on an iMac running OSX 10.10.5.

I create a new project. I use the OpenLayers plugin to show an OSM background of a part of Mayfair in London. I now use the Georeferencer to add an 9Mb .png (copy of a web map) and import three points. All the SRS/CRS are set to EPSG:3857. Transformation settings are linear.

[[This Dropbox folder] https://www.dropbox.com/sh/cazhx5j2amz55lh/AACpWfnsS5qS-UBV8vqikwWpa?dl=0] contains a copy of
  • the 9Mb map I'm trying to transform
  • the points I have previously saved
  • a screen copy of the transformation settings
  • a screen copy of the QGIS window showing the GCP table and the two maps
    At this point I run the transform and I get the message: Transform failed: Failed to compute GCP transform: Transform is not solvable.

I have no idea of what is going wrong here. I have managed to use exactly the same process (with a different but very similar .png) and it has worked in the past (but not recently), but any attempt to add a second file usually seems to fail. Trying to add the map that did work to this project also failed in the same way. Many other images/points have failed as well. I've also reduced the PNG to a 1.6Mb jpg and this also fails in the same way. I have removed all plugins other than the OpenLayers plugin and it still fails.


#1 Updated by Giovanni Manghi over 6 years ago

  • Status changed from Open to Feedback

Please remove the OpenLayers plugin too (which is source of issues) and try with the QuickMapServices instead (to get the same background maps, but better as they are pulled using standard WMS services).

#2 Updated by Giovanni Manghi over 6 years ago

  • Resolution set to not reproducable
  • Status changed from Feedback to Closed

Closing for lack of feedback, please reopen if necessary.

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