High Accuracy GPS , leica gg04 plus, Field Maps on Android. Altitude is incorrect

[LaurenceLanglois1]

I have 'Zeno connect' running on the Android Tablet. With This Result

This is the result From the point I took in Field Maps.

The Altitude is not in meters, it is about a quarter of the live results on the screen.

Any suggestions? 

This is the settings from the "Zeno Connect' screen.

I could not get Z values to show up.

Thanks in advance Larry

[BillFox]

looks like that one is on the steps of the Sharon Public Library at

11 N Main St, Sharon, MA 02067

[LaurenceLanglois1]

I was on a known benchmark where I took my point.

[LaurenceLanglois1 · Accepted solution]

Thanks for the replies. I am going to make a new more specific post:

I just purchased a new GPS unit ‘Leica gg04 plus’  

I am using an android tablet.

The 'Leica Connect app’ displays the correct elevation 72.23 meters Orthometric Height.

 But in 'Field Maps' it stores an altitude of 44.09 (Height above ellipsoid (HAE)).

Does anyone have this Leica gg04 unit, and recording the elevation correctly without post processing?

[LuisaC]

Not sure if this is something you're still working out, but we've run into this issue as well with our Trimble R2s. What we found is that when Field Maps is configured for high-accuracy recievers the ellipsoidal height is recorded in the altitude field, but the z-value captured in the feature's geometry should be the orthometric height from your reciever. There are some vague references to this issue in the field maps doc pages that I can track down if you're interested.

To display the correct elevation for our users, we did end up creating a new "orthometric height" field and copying the z-value to it with an arcade expression in our field maps collection form. 

Hopefully this is is still relevant for you! 

[JeremyJones1]

Did you do your arcade expressions in AGOL?  I've tried the pop up method and it just does not work.  I also tried attribute rules in pro before publishing the layers for use in fieldmaps and that didn't seem to work either.  I really wish they would fix this.  My users really want to see the elevations in feet and accuracy in inches etc. when the data point is collected.

[LaurenceLanglois1]

I was able to get z to populate with command Geometry($feature).Z 

When I created the feature, I checked the box for collect Z information. 

This is somewhat worthless because it is post-processing procedure.  I want the elevation taken during the point acquisition.   I confirmed there is an official  ESRI enhancement request for this to gather elevation in the feature. The elevation number shows up on my Zeno connect software. I used third party Apglos Survey Wizard and it collected the correct elevation. 

[LaurenceLanglois1]

Hello LuisaC,

I was able to calculate Z value, with an arcade value online. I could also do it with 'calculate geometry' in ArcMap pro. But I still wish it was automatic.  I made an ESRI case to highlight this upgrade. I am working on changing the 'base map' in Field Maps to my State Plane projections, but I was unsuccessful on my first try. 

I think my X and Y are off due to the projection changes also.

This is not as easy and seamless as I hoped.

Larry

[tikola]

I have now spend a lot of time with this topic in Finland and conclution in early 2025 is that Leica extenal GPS devices (FLX100 in my case) works like a charm if working in XY. It requires just adding additional location source via bluetooth and thats it - extremely simple.

When you start measuring heights things get bit more complex and key player is the basemap used in WebMap. So Field Maps with external (and internal) location sources follow in recorded values the coordinate system used in basemaps. If you are working with Esri global basemaps you get coordinates in Web Mercator and height in WGS84 ellipsoid. To get them to your local orthometric height you must switch basemap to your local projections and elevation systems.

While doing this you must also remind that height in GPS metadata attributes might still differ from ones stored in geometry attributes.

So key thing if you end up in troubles with height systems is the basemap used in your webmap.

My case is Apple IOS and I have a feeling that we might see some differences in Android cases. In practise external GPS works more or less equally in both OS, but device internal GPS seems to work in Android in a way that heights tend to stick in WGS84 while with same settings Apple IOS gives local orthometric heights as expected. So there could be some difference how different OS provide GPS data to applications.

The key thing is that if you get either Ellipsoidal or Orthometric height the issiues is mainly a Field Maps basemap dependable.

[LaurenceLanglois1]

I have not been able to setup a Basemap on ArcGIS online using my Local State projection. And then choose it in field maps.
Larry

[tikola]

So are you saying that just opening any Local State data and using that as a basemap does not work? I can not help much on that as In Finland I have no Local State projection but this is the process I use with local files here. So I do not click the add data but I rather open the data dialog and there instead of opening it I just click use as a basemap option. I agree that getting your own data might be a bit hard as basemap should be some defined layer type. Not all feature layers can act as a basemap. 

My screenshots are in Finnish language but you should find right clicks by following ones rounded with yellow. That path leads you to but some Tile Image layer as a basemap. This is how I have done it.