RX GCPs coordinate system and geoid in external app

  1. Using Emlid Flow and Reach RX
    2: I want to capture data with another app
  2. I want to use UTM 32N ETRS89 - DVR90
  3. Using the inbuild Survey project - the coordinates are fine. But using another app I´ll get WGS84 coordinates and another geoid.
    Is it possible to get the wanted transformed data in another app as QField or Mergin

Lene Fischer
University of Copenhagen

How are you getting the data to the other app? And are you using the 3rd party app to survey in real-time? If your using a NMEA string, you will not get the UTM coordinates your are looking for, but latitude and longitude instead. I would look into the settings of your 3rd party app and see if WGS84 to UTM can be done there


Thanks for your answer
I can easily transform long/lat tol UTM in either QField or Mergin Maps. Both have underlying QGIS to do the calculation - it is the transformation of the height to danish DVR90 that are the issue.

Can you load a geoid file for dvr90 into qgis?

Hi Lene,

As @snillor999 said, NMEA contains geographic coordinates and 2 fields of elevation data: orthometric height and geoid-ellipsoid separation. Usually, apps receiving position in NMEA can sum up these values to calculate ellipsoidal height and then apply any necessary geoid model if it’s supported.

I am not sure if this is possible in QField or Mergin Maps, but I have checked that Emlid Flow supports ETRS89 / UTM 32 N with DVR90 heights. Why don’t you collect the data directly in it? Do you need any special features for your project?

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Hi Julia,
I know that Emlid Flow support the wanted coordinate and geoid, but I use Mergin Maps - which are directly syncronized in the sky and with my desktop QGIS.
Using Emlid Flow I have to Export a shapefile, Import shapefile and change it into a geopackage or database.
Secondly I can capture or edit points, lines and polygons in Mergin and QField. Thats´the reason for excluding Emlid flow.
Lene Fischer

Hi Lene,

Thanks for clarifying!

So do you need data to be in GeoPackage or database for further work? How do you use it? I just think that I can register it as a feature request. But to do that, I need to gather more info about how it works for you.

Emlid Flow supports working with points and lines. I’ve linked the guides to our docs to learn more about it. As for polygons, I’ve noted your request. Thank you!