"Just hover a drone over them and record downwards" seems a lot harder! What a world where that's considered easier than other sensing options. I think vision

"Just hover a drone over them and record downwards" seems a lot harder! What a world where that's considered easier than other sensing options. I think vision is a good plan for a lake, with wide baseline. It's not great for a street with oncoming traffic. Turns out, however, that there are COTS radars that will work in the <100m range so I might go that route for the house, and try vision for the lake.