The Finished Maps section of the Guild here ( https://www.cartographersguild.com/forumdisplay.php?f=36 ) has thousands of maps that can be useful as...
Cartography is the art of abstraction to fulfill a purpose. You may find that several simpler maps (or layers on a simpler map) are much more useful...
https://docs.qgis.org/3.34/en/docs/training_manual/processing/no_data.html might be helpful for using QGIS to add two layers and a constant together....
Experimentally leaning into the pop art nature of this. Possibly this reads better than the dark background? Then that leaves me with the dark purple...
Merging the brightest and darkest parts is not too hard but the arbitrary gradient in the middle would be a bit more difficult unless you can apply a...
You've got the general form down, but it's (as it almost always is) how the details are arranged. Looking at the example map, the initial thing that...