Ben Discoe has a good point on the first post, specifically:
As I see it, the biggest gap is not in smoother uploading or cloud processing in the cloud. The biggest gap is Ground Control Points. Until there’s a way to capture those accurately at a prosumer price point, we are doomed to a patchwork of images that don’t align, which is useless for most purposes, like overlaying other geodata.
Ben’s right of course. If drone data is produced, analyzed, and combined in isolation, especially while prosumer and consumer grade drones don’t have verifiable ground control, the data can’t be combined with other geodata.
The larger framework that I’m proposing here side-steps those issues in two ways:
- Combine drone data with other data from the start. Drones are a platform and a choice. Open aerial imagery, the best available, should always be used in a larger mosaic. If Landsat is the best you’ve got… Use it. If a local manned flight has better data… use it. If an existing open dataset from a photogrammetric / engineering company is available… use it. And if the drone data gets you those extra pixels… use it. But if you don’t have ground control (which you likely don’t), tie it into the larger mosaic. Use that mosaic as the consistency check.
- The above isn’t always practical. Perhaps the existing data are really old, or are too low in resolution. Maybe the campaign is so big and other data sources so poor that the above is impractical. In this case, internal consistency is key. Since OpenDroneMap now leverages OpenSfM, we have the option of doing incremental calculation of camera positions and sparse point clouds. If we have 1000 images and need to add 50, we don’t have to reprocess the first 1000.