Beautiful Global Projections – Adding Custom Projections to QGIS
This year we are celebrating Gerardus Mercator’s 500th birthday. We have all grown very accustomed to his Mercator projection but I want to take the chance to explore some alternatives:
Radical Cartography features an extensive projection reference compiled by Bill Rankin. One of the more exotic projections is “Van der Grinten I” by Alphons J. van der Grinten, 1898. It has a “pleasant balance of shape and scale distortion”. The “boundary is a circle” and “all parallels and meridians are circular arcs (spacing of parallels is arbitrary)”.
Using the name, we can try to find the projection definition on Spatialreference.org. One of the definitions that works well in QGIS is “ESRI:53029 Sphere Van der Grinten I” with the following proj4 string:
+proj=vandg +lon_0=0 +x_0=0 +y_0=0 +R_A +a=6371000 +b=6371000 +units=m +no_defs
In QGIS Settings – Custom CRS, we can add this projection to the list of available CRS:
- Press the “Star” button to add a new empty entry”
- Add the Name and proj4 string
- Press the “Save” button to make the changes permanent
Custom projection dialog
Once this is done, “Van der Grinten I” can be selected for on-the-fly reprojection. I’ve been using NaturalEarth’s land and ocean dataset. The result might not be a perfect circle (due to the coarseness of the dataset) but I find it very appealing:
Van der Grinten projection
