Mapping as in.. drawing the outlines of buildings and computing the square footage yourself?
https://www.datacenterfrontier.com/cloud/article/11431213/sc...
A decade ago, there was a burst in construction and in some places the bottleneck was not getting the machines or electricity, but how fast they could deliver and pour cement, even working overnight.
Also how do you know their efficiency? Google might have less space but also a way to pack twice as much compute in the same place.
Like I said, this is impossible to know without a lot of insider information from a lot of companies.
Of course, it's all estimates. You can get fancier and count generators and transformers and stuff too.