Elevation errors

I processed a 112 JPEG DTM. I had 6 GCPs and able to tag GCPs in 47 of the images. GCPs were taken with a RTK GPS system.

I processed with the GCPs translated to WGS84 CRS, but kept the elevation in elipsoid units.
The DTM GSD was ~ 12".

When I checked my 3D accuracy against the GCPs, the error was dominated by elevation error. I’ve included a picture below of the elevation error by GCP in inches. The X/Y errors were small by comparison. Roughly 1/5th the size of the elevation errors at the same location.

IdeasGCP error

Which camera model did you use?

I let the S/W derive the camera model. I don’t know how to interpret this JSON information. Which values are the three key angles.
“dji fc220 4000 3000 brown 0.7222 rgb”: {
“p2”: -0.00034598784474465597,
“p1”: -0.0008177793457538107,
“width”: 4000,
“projection_type”: “brown”,
“height”: 3000,
“k3”: 0.07509978154248094,
“k2”: -0.09184856295972643,
“k1”: 0.03064830716936707,
“focal_y”: 0.753030497492569,
“focal_x”: 0.753030497492569,
“c_y”: 0.008408309493637132,
“c_x”: 2.8517284260051e-05
Thanks for your help

Did you bring the drone to a full stop while taking the pictures? ODM does not have rolling shutter correction (yet), so perhaps that could have played a factor.

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Yes, but it shouldn’t have been a factor as the Mavic has a mechanical shutter.

As far as I know, the Mavic does not have a mechanical shutter. In that form factor, it certainly doesn’t have a leaf shutter, which is the only shutter type that doesn’t require rolling shutter type correction. Focal plane shutters have the same issue as rolling shutters, just less so. Leaf shutters do not.

Without rolling shutter correction, anything but a leaf shutter will result in significant errors if the aircraft isn’t stopped for each shot.

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