If you've got a DJI drone, you can do this for tens of dollars using inexpensive software and services.
I've used the SparkPro iOS app (for mission planning and automated flight with a programmed set of waypoints with camera instructions).
And this service who'll stitch images together (for free for small enough areas. I needed a plot about 200 x 200m, and its didn't cost anything):
https://www.mapsmadeeasy.com/
Takes a bit of thinking and experimenting to get a good result. You need to get 4 or more times overlap for everything you want good stitching and elevation data from. (And the DJI specs on their cameras are misleading. I wasn't expecting the FoV spec to be diagonal, so my first attempt didn't overlap as much as Idol intended...)
I've used the SparkPro iOS app (for mission planning and automated flight with a programmed set of waypoints with camera instructions).
And this service who'll stitch images together (for free for small enough areas. I needed a plot about 200 x 200m, and its didn't cost anything): https://www.mapsmadeeasy.com/
Takes a bit of thinking and experimenting to get a good result. You need to get 4 or more times overlap for everything you want good stitching and elevation data from. (And the DJI specs on their cameras are misleading. I wasn't expecting the FoV spec to be diagonal, so my first attempt didn't overlap as much as Idol intended...)