If this is in the wrong place, please feel free to delete/move.
I have two requests which may (or may not be) of use to others.
Firstly, in the display window there are options to display in things in colour (eg height, crop health) using a variety of colour ramps. Would it be possible to add a simple greyscale to the slider menu?
Secondly, for those not using GCPs, other cloud-based systems (eg MapsMadeEasy) make use of the EXIF data from a single image taken on the ground against which elevation can be calibrated. Is this a feature which could be incorporated into WebODM, if not already?
Still loving it, so if these requests are not easily implemented, it’s not a major issue. For example, the greyscales can be done in QGIS - it would just be nice to have them immediately to hand.
Grayscale Color Ramp
1A) Great question. Should be do-able. Just have to see how we implement them. Hopefully GPL files so we can get a nice, wide library from QGIS and others
Ground-Elevation Image Workflow
2A) Really interesting… This workflow seems to make a number of assumptions about how much inaccuracy you’re willing to stand, as a regular single image taken at the ground level by the same platform should likely still have just as much Z-Axis inaccuracy in the GPS data as the data taken in the air, if not more (multipathing, possible loss of satellite views due to site terrain, etc.)
2B) Have you used this workflow? Does it actually help align the data with the actual site elevation, despite the limitations?
Re: 2B I have used it, and whilst obviously it is not accurate to cm level, it does help give the the DEM more realistic values on the Z Axis. By using the ground based image as “0 altitude” and (I think) relating it to its calculated elevation above sea level, the EXIF data from DJI drones can then be calibrated to give a reasonable approximation to altitude above sea-level rather than AGL, if you see what I mean?
This is taken verbatim from the MapsMadeEasy site:
" Ground Reference Image
Some cameras, like those on DJI’s drones, only record the altitude relative to the takeoff location.
To allow us to correct for it, please include an image that was taken on the ground at the takeoff point.
If no image is included, the elevation map will only be a relative one and will not give accurate elevations above sea level."
(I suspect this might be more tricky to implement, as I guess it needs to search online for the true altitude of the ground based reference image - probably like the Drone Deploy app using NASA/Mapbox and “other sources” for elevation data)