Better Accuracy in Field Maps with Trimble DA2

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05-01-2023 07:41 AM
SeanNagy1
New Contributor III

My company recently acquired the Trimble DA2 GNSS receiver to use with Field Maps and Survey123 for data collection. We did a test of accuracy by comparing points collected with Field Maps to actual surveyed points and in general the points were off by about 6" all in the east south east direction. I know our survey crews use PA83-SF with US Survey Foot units as their coordinate system. I believe the standard for ArcGIS online with basemaps uses the Web Mercator with meters as their unit. Is there a way to set Field Maps up to collect in PA83-SF so we don't need to worry about projections that might skew data? I would also prefer obtaining elevation information in feet instead of meters and currently have to use arcade to obtain the elevation at the MSL and then do a calculation into feet which doesn't auto populate the elevation field when bringing into CAD. I included the current Trimble Mobile Manager and Field Maps profile settings for reference.

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4 Replies
RhettZufelt
MVP Frequent Contributor

If your basemap(s) and data are in PA83-SF, you data will be collected in that.

Howerver, you will still need to get the profile "converting" the GIS data appropriately.

R_

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SeanNagy1
New Contributor III

Any idea on the settings i apply to Trimble Mobile manager and Field maps for the GNSS profiles? I can have the NAD 1938 2011 as the GNSS in Field Maps and can add the PA83 SF coordinate system to match the new basemap but i am unsure of the datum transformation to add

 

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RhettZufelt
MVP Frequent Contributor

Sorry, I do not.  I'ts been some time since I used a Trimble with ESRI app, and that was with collector, and don't have anything to test nowadays.

R_

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TracyGarrison
New Contributor III

I am not familiar with PA83-SF but if that is NAD 83 Pennsylvania State Plane South Zone (2011 adjustment) and you have GNSS setup as GCS NAD 1983 2011 then there would not be any datum transformation because they are both based on the same datum "NAD 1983 2011 adjustment".

But, in order for this to work you need to have an ArcGIS Portal so that you can create your own basemap.  The basemap would have to be in the NAD 83 2011 Pennsylvania South Zone coordinate system andin survey feet.   Then when you collect the data with the DA2 the point saved will have the X,Y for that state plane zone in us ft.  The Z will be in Meters (sorry) and be from the Geoid18 CONUS that you set in your Trimble Mobile Manager.   

Use arcade to display the data in the portal var xpoint = geomertry($feature).z*3.28083333333 for z.

If you go into ArcGIS Pro you can add the Feature Service and add three fields N, E, Zmeter and use calculate Geometry using the appropriate  property for each field:  For the Field "Zmeter" the property would be point z coordinate but, this will be in meters.  Then create new field "Z" and calculate that field to be equal to Zmeter*3.280833333.   The N, and E fields would not need further calculations.

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