What Coordinate System is Best?

05-05-2023 01:37 PM
Occasional Contributor II


I am using ESRI Field Maps in association with ArcGIS Online hosted features to collect wetland delineation data.  I am using an iPhone connected to the Trimble DA2 with Catalyst 60.  Was wondering what coordinate system I should be using for the hosted features?  Should it be WGS 1984 Web Mercator Auxiliary Sphere for x,y and WGS 1984 for z?  Should it be WGS 1984 all around?



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New Contributor III

WGS84 would be the safest bet as this is the default for the map and requires less reprojecting. 
for z, make sure your feature class is Z-enabled, in the Trimble Mobile Manager App under GNSS settings download the proper Geoid (geoid 18 conus in in continental US) while these values will not `be represented in the FS fields (altitude is always the HAE meters) you can use field calculator or an expression in field maps to call the Z value that DOES get passed from the GPS to the feature. Round(Geometry($feature).z2)

i have experimented with many different FS coordinate systems and they all seem to work fine. had a couple concerns and was sweating pretty hard. the biggest mistake i see is that users can keep the position source as integrated and the profile set to what the DA2 needs and this results in a large shift of features.

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