Select to view content in your preferred language

Issues with altitude values when using external GNSS with Collector

06-08-2021 02:35 AM
New Contributor III

Good day,

We are testing Emlid Reach RS2 for measuring utilities. So far our surveyors used Trimble but we are looking to involve more people into the survey process by letting them use Arcgis Collector and some external GNSS device. Our choice for external GNSS receiver was Reach RS2. However, there are some issues that we observe with a new workflow.

First of all, out tests using ReachView native app showed very nice results both in horizontal and vertical accuracy. Recently added vertical datum for our region (Iceland) works very well and all height values are in accordance to the National Land Survey data. However, when same locations are measured in Arcgis Collector, the altitude always varies and sometimes the variations are up to 0.5 - 1 m. I did several tests and all of them showed stable altitude in Reachview app but ranging values in Collector. I wonder what might cause these variations. Has anyone experienced the same issues using external GNSS (particularly Reach RS2) with Arcgis Collector? 


4 Replies
New Contributor III

Hello mykola,

We have a similar problem with measuring height in Field Maps/Collector in Germany. I'm not familiar with the icelandic datum, so I can't say, that it is exactly the same problem. Field Maps and Collector seem to have a problem with interpreting the data, the GNSS Apps are providing. If I understood everything right, this is only a problem outside of the US, because there they are measureing the Height above Ellipsoid. I collected everything I know here:

Measure the orthometric height in Field Maps - Esri Community

My hope is, that we can find more people with this Problem, so esri has a reason to fix/implement this.

Good Luck and Cheers!

New Contributor III


Thanks you for the provided link. I haven´t found anything on this topic online so I decided to ask the community. From the link it seems that more people have some issues with heights in esri apps. I hope Esri takes a look into this issue otherwise the use of external GNSS might not be as reliable as we would like it to be. 

New Contributor III

I am also experiencing a similar issue here in Canada while using the Emlid Reach RS2 and ArcGIS Field Maps. The value that is stored in Fields is the height above ellipsoid. After converting to orthometric height and comparing to reported values, the accuracies I am seeing are quite good. I have inquired with ESRI and it is my understanding that this fix will not be coming for a while yet.

Occasional Contributor

What was the reply you got from Esri? I am not familiar with Emlid but Field Maps has to connect directly to Trimble and Leica receivers and not via mock location as integrated provider. Via mock location FM can only read lat long and HAE. I am interested in knowing how you connect FM to Emlid. Thanks


0 Kudos