Researchers used a drone to take pictures of a river in France in 2014 and 2015. They used these images to make detailed maps of the river's shape and erosion. The drone images were very accurate, showing changes in the river's path and where the banks were eroding. The maps made it easy to see how the river was changing over time. This method could help people who manage rivers to keep track of changes and plan how to protect the land around them.