Bug report #12795

Georeferencer generates incorrect GDAL script when input file is JPG

Added by Casper Børgesen almost 10 years ago. Updated about 6 years ago.

Status:Closed
Priority:Normal
Assignee:-
Category:C++ plugins/Georeferencer
Affected QGIS version:2.8.5 Regression?:No
Operating System: Easy fix?:No
Pull Request or Patch supplied:No Resolution:end of life
Crashes QGIS or corrupts data:No Copied to github as #:20891

Description

Problem:
When georeferencing a JPEG image QGIS return telling the transformation could not be made.

Why:
According to the GDAL script QGIS can generate, the process is split into two steps:
  1. gdal_translate
  2. gdalwarp

Script:

gdal_translate -of GTiff -gcp ... -gcp ... "original.jpg" "temp.jpg" 
gdalwarp -r near -tps -co COMPRESS=LZW -dstalpha "temp.jpg" "result.tif"

The input and output argument provided to gdal_translate is both with JPG extension, while the -of argument is GTiff. gdalwarp cannot handle a GeoTIFF image with JPG extension.

Solution:
So either should the first process set the -of argument to JPEG (in this instance) or change the output extension to TIF.

History

#1 Updated by Nyall Dawson almost 10 years ago

  • Status changed from Open to Feedback

I can't reproduce - is this only when using the generated GDAL scripts? Does the georeferencing work OK from within QGIS itself?

#2 Updated by Casper Børgesen almost 10 years ago

Nyall Dawson wrote:

I can't reproduce - is this only when using the generated GDAL scripts? Does the georeferencing work OK from within QGIS itself?

I reported this problem because my users couldn't use QGIS directly and I had to create a batch script to solve the problem. Thats why I discovered the JPEG/TIFF problem.

I have a rather large (30MB) JPEG image and when I use QGIS to georeference it, I get the error "Failed to compute GCP transform. Transform is not solvable.". When I correct the JPEG/TIFF problem in the correspondig GDAL script generated by QGIS, the same transform succeeds. Thats why I thought the problem indeed was the extension.

I have just tried though with a small JPEG image and QGIS was able to transform it. I have tried both in QGIS f4c3f3d (latest weekly for windows).

Could this be image size related somehow?

#3 Updated by Nyall Dawson almost 10 years ago

So... to clarify, there's two issues. One is that the generated GDAL script is wrong, the second is that QGIS can't transform your file. Can you open a second issue for the failing to transform issue, and attach a link to the data and GCP points file?

#4 Updated by Nyall Dawson almost 10 years ago

  • Subject changed from Georeferencer sets wrong extension when inputting JPEG to Georeferencer generates incorrect GDAL script when input file is JPG

#5 Updated by Giovanni Manghi over 9 years ago

  • Operating System deleted (windows)
  • Affected QGIS version changed from 2.8.1 to 2.8.5
  • Status changed from Feedback to Open

#6 Updated by Giovanni Manghi almost 8 years ago

  • Regression? set to No
  • Easy fix? set to No

#7 Updated by Giovanni Manghi about 6 years ago

  • Resolution set to end of life
  • Status changed from Open to Closed

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