I am new to QGIS.

I need to create both interior and exterior buffers around a country border, however MMQGIS does not allow me to create a buffer that is, for example, -10 km from the border. Now I'm forced to use the Vector, Geo Processing tool to create buffers with degrees but would rather use km or mi to stay consistent as I create buffers around the globe.

Could anyone advise with either method?

  • What QGIS version are you using? – Stu Smith Jun 5 '20 at 4:39

If you're looking to make a world map with a geographic (lat/lon) CRS I doubt if it is possible to apply buffers to it in any simple or meaningful way.

You could try transforming your lat/lon country polygons to EPSG:3857 (Spherical Mercator) and buffering these using a buffer value of (say) -10000 metres.

I don't know what your maps are for, but please note that there can be serious scale errors when using EPSG:3857. For more information you could try Googling something like "epsg 3857 scale errors".

Make sure you select 'Cartesian' when using the measuring tool.

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