score:9
For territorial changes, Wikipedia is a sufficient source. They happened in 1939-1945, and looking at every involved country you can trace them exactly.
For casualties, there is a unique book:
Micheal Clodfelter, Warfare and armed conflicts. A statistical reference. Volume 2 1900-1991. McFarland &Co, Inc. Jefferson, NC and London, 1992.
This book (2 volumes) is a unique source where all conflicts from 18 century to 1991 are covered, and the author did his best to estimate casualties. This is a highly non-trivial matter, as all specialists who tried to do this know. The casualties are divided by battles, campaigns etc. And either do not include civilian casualties, or least count them separately.
Upvote:3
Eventually what I did was:
The result is this visualization:
Red is USSR, black is Nazi Germany. The highlighted section of each curve shows a timespan of about one month.
Caveats: this data has not been validated, it's literally just reading in the number of pixels of the above vids then making a wild assumption about the numbers they represent in terms of deaths and territory, which means what the plot shows might be very far from the reality. Also, this shows total deaths (all fronts + civilian) which in the case of Germany evidently means this is not from just the Eastern Front, while territorial changes are only from there. So this is more like trying out an idea. But if I can get reliable data, this can be made realistic and the visualization itself I quite like as it turned out. And as far as I can tell, it does show the general trends relatively correctly.