I keep getting poor image quality after exporting (high DPI) from the map composer in QGIS.

The original Geotiff is 254 DPI and has great image quality (smooth lines).

After opening in QGIS and exporting from Map Composer, the lines are jagged.

Best quality with PDF, but still not good enough.

Is there something that QGIS is doing to the TIFF when importing?

  • Are you using on-the-fly reprojection where the input TIFF and project are not in the same projection? – BradHards Oct 10 '15 at 3:03
  • In the composer what resolution have you chosen for the output raster? – nhopton Oct 11 '15 at 9:51
  • Yes I am using on the-fly-reprojection. Don't really understand what you mean with the TIFF and project being in the same projection. Sorry I am a noob with Qgis. I am just using it to make maps for hiking trips. I Just open a project. Import a Raster Layer. change the CRS to UTM 31N. Then I add lat/long grids and UTM grids in the map composer. I export the map as PDF. Where do I chose the resolution for a pdf? If i export as a image file and use 300 DPI or 254DPI I get the same poor quality. – Toshii Oct 12 '15 at 1:49
  • Have you tried changing the resampling method for the Geotiff layer? The default is to use nearest neighbour but you might get better results if you change it to bilinear / average. – mixedbredie Dec 23 '15 at 14:18

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