I am using QGIS 3.4.

I'm creating a pretty simple map that shows major roads, cities/towns, and state/county boundaries for 4 northeastern U.S. states. All but the boundaries have labels (not buffered). I was successfully exporting large PDFs (22x36, 300 dpi) of this map as I progressed to make sure my file wasn't too large. At a certain point, my map stopped exporting, so I started turning layers off to see what would and wouldn't export. Now I'm at a point where I'm lucky if I can export just the basemap at 75 dpi. My maps renders at the same speed, but I get the 'bad allocation' notice within seconds of attempting to export anything.

Any suggestions?

  • The map displays on your screen at a much lower dpi than you're exporting to, so it's not surprising that you're not having rendering problems even though the export fails. You might need to export the map in tiles and stitch them together in a different program (hopefully you have Adobe Acrobat Pro; otherwise try exporting them as images, put them together in an image-editing software, then convert to pdf). – csk Jul 25 '19 at 16:10
  • There are multiple ways to make a tiled export; you can do it in print composer by manually setting the image extent, or you can make an atlas, or export from the map canvas, etc.Here's a (rather old) tutorial about using "QGIS from command line" (I'm not sure if that's still exists in QGIS 3). Those are just some examples. If you look into it you'll find other methods, including writing a python script. – csk Jul 25 '19 at 16:13
  • You might need to use data-defined label settings, otherwise the labels tend to move around so they won't line up between the different tiles. – csk Jul 25 '19 at 16:15
  • If your other layers are all vectors, you can probably export them at full size and resolution in a single piece. Then you only need to do the basemap in pieces. High-resolution rasters tend to be what cause the problem with high-resolution exports. – csk Jul 25 '19 at 16:18

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