There was a system that apparently determines gunfire origin from triangulation reliably in cities too. Both combined sounds like power data (no pun intended).
I believe that system is called ShotSpotter. There are a couple drawbacks (coverage isn't perfect), and I've heard someone claim that it is nearing nanny-state levels of surveillance. I don't think the microphones are clear enough to get much more than a blur of noise, but I'm not sure.
A few years back I was in the Phoenix area for New Years eve, and the local police were using ShotSpotter. There's a tradition in parts of the city to fire shots into the air in celebration, but those bullets come back down and have killed a few people.
Yep, they used these systems in Iraq and now they're setup in some of the more dangerous areas near me.