This map is fascinating. It looks to have started from a satellite view of the Zone region just south of the CNPP, but there's a few interesting edits. I've opened the same region in google maps and will compare the differences.

• The entire CNPP and cooling pool (I think) area is unchanged from the map.
• Chernobyl (town) and the swamp north of it (I believe this inspired the boats in Yanov) is intact, but scaled up from what it looks like on the real map. I've always wondered why we never saw the town in any games.
• In the lower left there's the DUGA-3 antennae, which is in the right position compared to the CNPP, but like Chernobyl is scaled up in size.
• The rest of the satellite image is pretty much empty, so everything else is (I think) new additions. The most obvious one is Rostok. Some of them (like the building/complex southwest of Rostok) has been clearly cut-and-paste from a satellite image - that particular one is located at coordinates (51.246022, 30.160394). I imagine all of the additions are pieces of the satellite map cut up and moved around, as they all match the look of the map (except for Rostok).
• The river is definitely new, the swamp doesn't have any river like that leading into it on the real map.

I can't find locations for any of the other new areas on the map, but I'll keep looking. My thoughts at this point is that this map would have to be huge. The CNPP to the north was big enough to take up an entire map in SoC. I would guess that the maps in CoP were not larger than 3x that map. I would say this map is a minimum of 10x the size of SoC's CNPP map, unless they make the power plant unrealistically small.