Custom geoid in d2m?

[Pål_Herman_Sund]

Total d2m newbie here, and have just got same data related to a supportcase (Norwegian distributor).

My client has GCP's which are surveyed by professional RTK and corrected for the (quasi)geoid which is the basis for the national height system (NN2000). Horisontal reference is EPSG:2583x (x = 2 or 3).

From one EXIF I can see lat/longs (DMMSS.ss) and an AltitudeRef= SeaLevel and an altitude in meters.

So far so good, but what to do with vertical settings in d2m:

• the geoids available, none are the correct for my case. Can I make a custom geoid? (I have a textfile with the datapoints for the geoidmodel for NN2000)
• my initial idea was to drop geoid settings and just set a constant height. The geoid undulation is probably non-existing in his small projects (constant is probably good enough. Would that still provide good results?
• Is the altitude of the frames a problem when there are GCP's at all? would believe the GCP's would tie the model to ground and not at some "random" height given by the EXIF's

Might even be some of you are willing to share some experiences

best

Pål Herman

[CodyBenkelman]

Pål

Drone2Map 2.0 (coming this summer) will have more datum support.  Until then, you can simply use a constant elevation value, but this is only used for the initial estimation of scale/resolution.  If you apply GCPs, they define the final height values for 3D products.

Cody B

[Pål_Herman_Sund]

Thanks Cody. Got it going with ellipsoidal height+constant for the camerapositions (and of course also with EGMxx as a choise). 

After the initial processing and connecting the GCPs is the solution updated, or is it time for a new estimation with the improved initial POS values?

Best

Pål Herman