2

I want to create a geo-referenced tif or pdf to import to Avenza PDF map.

The Feature list for QGIS 2.16 states that composer creates a geo-referenced file by default.

"The existing option to create a world file has been separated from the map selection for georeferencing. The new behaviour is to always georeference outputs, and only create the separate world file if that option is checked." - reference https://www.qgis.org/en/site/forusers/visualchangelog216/index.html#feature-georeference-outputs-eg-pdf-from-composer

I have been able to create a georeferenced image but it is of no use and will not load into my map because it is in pixel coords.

C:\output>gdalinfo r4_composer_ix.tif
Driver: GTiff/GeoTIFF
Files: r4_composer_ix.tif
Size is 7015, 4960
Coordinate System is `'
Metadata:
  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
  TIFFTAG_XRESOLUTION=299
  TIFFTAG_YRESOLUTION=299
Image Structure Metadata:
  INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0, 4960.0)
Upper Right ( 7015.0,    0.0)
Lower Right ( 7015.0, 4960.0)
Center      ( 3507.5, 2480.0)
Band 1 Block=7015x1 Type=Byte, ColorInterp=Red
Band 2 Block=7015x1 Type=Byte, ColorInterp=Green
Band 3 Block=7015x1 Type=Byte, ColorInterp=Blue
Band 4 Block=7015x1 Type=Byte, ColorInterp=Undefined

Is there a trick to getting the output to be georeferenced in the EPSG the project is using?

I also cannot get a '.tfw' file created when I toggle 'Save World File' On.

1

I have found that QGIS 2.8.1 creates a world file based on the project EPSG from the 'composer' when the world file toggle is set to on. So maybe something is not working for QGIS 2.16.

And to create a Geospatial PDF from this output there is some very good points from this posting where Jakob responded (Translate (Convert Format)); Can QGIS export Geospatial PDF for Avenza PDF map app?

  • It works for me with QGIS 2.16.2. Did you set Print as raster and selected a Reference map? No world file has been created, but gdalinfo reports the extent correctly. I have no Avenza to test that. – AndreJ Sep 29 '16 at 5:33
  • @Andrej I followed your steps and it works for me now - Thank You. – Ben Sep 29 '16 at 6:59
0

I've tried exporting to GeoTIFF and Geospatial PDF with inconsistent results. According to the documentation, print composer should create a geo-referenced file by default as long as a CRS is set and in the Print Composer Composition > Export Settings > Reference Map is set to the current map. It is not necessary to create a world file for these formats since the spatial reference is embedded in the file.

I've found that sometimes I am able to export a geo-referenced image, then later using the same data with the same projection and settings I am not. Sometimes changing the projection or deleting and re-adding the map to the print composer will allow me export a geo-referenced file, but again sometimes not.

I would recommend trying the export a few more times - restart QGIS, create a new print composer, copy the layers to a new document, etc. until something works.

You could also export to JPG and save a world file (jgw). You can import a Zip file into Avenza with a JPG, JGW, and a PRJ or WKT file. QGIS does not create the PRJ/WKT file but you can download one for your coordinate system from spatialreference.org.

  • I have had similar experience, but found that it was because something had changed in my layout maybe the content had moved and if I hit the button in Composer > Item Properties > Map 0 > Extents > "Set to map canvas extent". I seem to have success. – Ben Sep 30 '16 at 11:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.