text:  So you can start to see fences. You can start to see details that are important, like sandbags, for example. So what we saw was really, really helpful when using drones for mapping these informal areas. Imagine if you're a flood planner and you need to work to develop a flood plan for informal sediment. They are informal. Nobody made a plan of where a house would be, which means that you have no idea what's out there.