RTK ellipsoid height to orthometric/geoid height not working

[JamesBurton1]

Since downloading drone2map 2023.1 a few months ago I was never able to get my RTK data to project from ellipsoid height to orthometric/geoid heights. The only way to make it work was using ground control, but that defeats the purpose of RTK. I could not make it work despite all my attempts at selecting ellipsoidal Z coordinate systems for my Image coordinates and then using a geoid Z coordinate system for my project.

Come to find out I was doing everything correctly, but missing a crucial program called "ArcGIS Coordinate Systems Data", which you can view in Control Panel-Programs-Programs and Features. If you don't have that program, you need to download it from the ArcGIS Pro section on myESRI. 

Thanks to @CodyBenkelman for putting in the time to figure this out. 

[JamesBurton1 · Accepted solution]

This is the program needed.

[JerryBartz]

Not accessible by the above method on my computer, but it is also available at My Esri.com: Downloads .

[Pål_Herman_Sund]

@JerryBartz  @CodyBenkelman Thanks! a follow up 🙂 what with geoid-models not delivered with ArcGIS Coordinate Systems Data but the geoid model are in the bin-format? Think I saw some doc for this issue but could not figure out, most countries in Europe will have the issue with a national geoidmodel relative some ETRF/ETRS 1989 (or derived from) geodetic datum? Possible to add the Data as a user and configurate (in my case the Norwegians HREF2018 model for our vertical datum NN2000 and relative ETRS 1989?

[Pål_Herman_Sund]

That last post was late evening and with a cell phone 🙂 early morning now and in front of my pc. 
Reading again I do think I need help and what I am looking for is a vertical transformation "ETRS1989 to NN2000" vertical transformation based on the  geoid model HREF2018B_NN2000_EUREF89 which is freely available here: https://kartkatalog.geonorge.no/metadata/hoeydereferansemodell-nn2000/71a73064-59a5-4f03-a0b8-fa5c64...

With pure RTK based missions (no GCP) my workaround is so far to export the GPS data, correct heights (either by a constant shift or based on a raster I have made from the geoid model), and import back. Would be nice to have the geoid model available without these extra steps. If You could enlighten this topic @CodyBenkelman it would be much appreciated. Best Pål Herman

[JasonWeis_Westwood]

I believe I am having the same issue - getting Mavic 3E RTK imagery (HAE) to convert to NAVD88. I am using D2M v 2023.1.1 and have the ArcGIS Coordinate System Data installed, but the DSM keeps generating at HAE elevation.  Which Image and Project vertical coordinate systems did you end up using to get your process to work?

[Pål_Herman_Sund]

@JasonWeis_Westwood my only "success" (a limited one) so far is XY and Z set both to WGS84 for the imagery and WGS84UTMxx for XY and EGM96 for Z for the PCS. Have not had the time to do research since my post 3 weeks ago

[MelodyVeldorale]

I'm having this exact same issue.  How do you use the Coordinate Systems Data tool to solve it?  Can you only do that in ArcGIS Pro, or can you use the tool in Drone2Map?  I have the tool, but still can't figure this out.

Thanks!

[Pål_Herman_Sund · Accepted solution]

@MelodyVeldorale @JasonWeis_Westwood sorry I did find the solution but forgot to update. The answer is as @JamesBurton1 pointed out, the "ArcGIS Coordinate System Data". 

This program is available for download at My Esri, I do believe it is in use both for Pro and D2M and for sure a separate download together with D2M.

With the program installed I was successful when defining Image Coordinate System (ICS) heights as ellipsoidal and my Project Coordinate Systems (PCS) vertical as "ortometric" (NN2000 in my case). Was pretty satisfied to see the transformation in the processing report for sure 😄

In the installation directory you can have a look for what is available of geoids, in my case (Norway) C:\Program Files (x86)\ArcGIS\CoordinateSystemsData\pedata\vertical\europe\norway\geoid lists the 2 geoids I need. 

Please reach out if you guys need more assistance, hope you find this answer helpful. Best pH 

[CodyBenkelman]

Thank you for posting this Pål_Herman_Sund

For  MelodyVeldorale 

and others, there are no tools that you need to run - this is just a data package to support coordinate systems and transforms, and the same package works for both ArcGIS Pro and Drone2Map.  Once you have it installed, you'll have all the coordinate systems available.  As noted in the previous post, if you do not have this package installed, you can find and download from your MyEsri portal.

Note for anyone with an RTK-enabled drone (or PPK data) be sure to set your Image Coordinate System to agree with the drone data before processing.  RTK/PPK is almost always referenced to ellipsoidal height (usually WGS84 but you will have to verify with your drone), and the default for Drone2Map currently assumes input image data is referenced to the EGM96 Geoid (not ellipsoidal height).  See this recent blog for more discussion of RTK  https://esriurl.com/d2mRTK

Cody B