OpenDroneMap / OpenDroneMap/ODM
GCP with CRS and elevations in feet results in tilted dem
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Description
We are using a GCP point file based on a MA State Plane (ft) projection. This has x,y,z values in ft.
We noticed that this resulted in a tilted ground and that the GCP location elevations did not match the elevations originally input.
Digging into it we noticed that webODM converts the GCP file to UTM 18N and in the process converts the x,y to meters but does not convert the z.
This is understandable as this is typical of GIS processes that do not attempt to convert elevations.
Thanks for all of your work on this great software. A warning that elevations need to be in meters would help or a way to tell WebODM what the units are so it can do the appropriate conversion.
Converting the Z to meters completely fixed the issue.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
The issue does not name a file or test. Start by tracing the GCP reprojection path for MA State Plane feet into UTM 18N, then verify how z values are handled. Done means feet-based GCP input no longer produces a tilted DEM through unit-aware handling or a clear warning.
Written by the indexing model from the issue text.
Assessment
- Domain
- data
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100