If you have already designed a few maps in QGIS, you are probably aware of a long-standing limitation: Print Composer maps were limited to the project’s coordinate reference system (CRS). It was not possible to have maps with different CRS in a composition.
Note how I’ve been using the past tense?
Rejoice! QGIS 3 gets rid of this limitation. Print Composer has been replaced by the new Layout dialog which – while very similar at first sight – offers numerous improvements. But today, we’ll focus on projection handling.
For example, this is a simple project using WGS84 as its project CRS:
As you can see, the red overview frame in the upper left corner is curved to correctly represent the extent of the main map.
Of course, CRS control is not limited to maps. We also have full freedom to add map grids in yet another CRS:
This opens up a whole new level of map design possibilities.
Bonus fact: Another great improvement related to projections in QGIS3 is that Processing tools are now aware of layers with different CRS and will actively reproject layers. This makes it possible, for example, to intersect two layers with different CRS without any intermediate manual reprojection steps.
Happy QGIS mapping!