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Author Topic: force DEM on ground control  (Read 2174 times)

frank.stremke

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force DEM on ground control
« on: January 21, 2016, 01:12:45 PM »
hi
i have a project where the reference pane gives nice values for my ground control points usualy errors around 10cm (flight heigt was 500m) i have optimized the allignment but still the DEM created gives me on many ground control points elevation deviations of up to a meter. i understand that photogrammetry is limited in accuracy and that i can only get so much accuracy out of it but i am confused by the error values (and teh estimates) since they look ok and as expected but the final result Mesh and DEM is different from that estimated values in the control.
is there a wasy to force the model onto the gcp
thanks
frank
edit i was cheking it a bit more closely and it seems the errors are in the range they where before optimisation so it looks like the allignment was not realy changed with the optimization even if the values in the reference pane got better
« Last Edit: January 21, 2016, 01:24:08 PM by frank.stremke »

upland@mcsnet.ca

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Re: force DEM on ground control
« Reply #1 on: February 29, 2016, 09:55:03 PM »
make sure your cameras are unselected and your GCP's (markers are selected) before you optimize.  Set your accuracy paramaters according to your GCP accuracy.  this should bring your DEM (after you re-do your dense clould) to very tight with your GCP's.