No, a population heat map means it's darker over the cities. There's more reports in Chicago than say, middle of nowhere Montana because there are more people there to report. This map is reporting the locations people are when they report it is down. And the circles get bigger and darker the more reports from that area. So if it was down everywhere, you would see the biggest circles over the biggest cities, and smaller circles in smaller cities, just like in this map. You see NYC, Boston, Chicago, San Fran have the biggest ones, and then smaller cities like Minneapolis have smaller ones.