I'm working in the polar regions and make maps in different scales. The convention is to show e.g. the Antarctic continent with the prime meridian upwards on the map and polar stereographic projection. In this way, south is toward the center of the map and east is clockwise (and opposite for the Arctic region).
However, when working on higher resolution, I want to have north facing upwards on the map, both on the canvas and in the composer, even if the layers and my project are polar stereographic projection.
The rotate function for the canvas is really handy, and I know that I can also rotate a map in the composer and use an expression. This is how I do it today, but it's complicated as I have to change the rotation every time I adjust the extent of the map, due to the converging meridians near the poles.
I could imagine a couple of ways to simplify my work flow:
- A dream scenario would be if the center of the view was always be rotated so that true-north faces upwards. Just as working in a Mercator projection.
- Or, how should I write an expression in the print composer to rotate the map to 360 - lon_c where lon_c is the longitude of the center of the map extent. My data is in UTM, but can I access the coordinates without writing a complex formula to convert meters to degrees?
- A last option would be to pass the canvas rotation to map rotation in the composer. Can it be scripted?
How can I achieve any of those options? I don't want to change the projection, just rotate the view so that north at center of the map is facing upwards in print composer.