Coordinate systems and transformations with collector and high accuracy GNSS GPS

[JeremyLinley]

We recently purchased a Trimble R10 receiver to utilize in conjunction with the Collector app, however we are experiencing some issues with the results we are getting. I am unsure if we have our unit profile setup correctly or if we need to have our data in a different projection/coordinate system. Essentially, our client wants the deliverable in NAD_1983_StatePlane_Illinois_West_FIPS_1202_Feet, so that is what our feature classes are in. It is important to note that we are utilizing an ESRI aerial basemap that is in WGS 1984 Web Mercator Auxiliary Sphere. Below is how we have the unit currently configured:

**Web Map Configuration**

1. Feature Service Data: NAD_1983_StatePlane_Illinois_West_FIPS_1202_Feet

2. ESRI Basemap: WGS 1984 Web Mercator Auxiliary Sphere

**Unit Profile**

3. GNSS Coordinate System: GCS NAD 1983 2011

4. Map Coordinate System: WGS 1984 Web Mercator Auxiliary Sphere

5. Datum Transformation: WGS_1984_(ITRF08)_To_NAD_1983_2011

Is it possible to accurately collect in our current coordinate system (NAD_1983_StatePlane_Illinois_West_FIPS_1202_Feet) or is that not possible?

[DougMorgenthaler]

Jeremy Linley‌ the configuration you've outlined looks fine provided you are using corrected GPS locations (e.g. from RTK) that are coming in as NAD83_2011.

[SharonUngerer_DNREC]

Did ArcGIS Online allow you to add a feature service in NAD83 to a WGS basemap?  I'm having trouble with my NAD83 State Plane features becoming WGS84 once I publish them to ArcGIS Online.  I thought they were in NAD83 but after checking the feature service details noticed the spatial reference was WKID 102100 (3857) which is WGS84 Web Mercator Auxiliary Sphere.  I'm wondering if your is doing the same and if not how are you keeping the local spatial reference on the feature hosted in ArcGIS Online?

I agree, the datum transformation listed is a good fit if the following are true:

• Feature service is indeed the NAD_1983_StatePlane_Illinois_West_FIPS_1202_Feet
• Trimble R10 receiver is collecting data using RTK corrections.

If the feature service spatial reference is not right that might be where the data issues in the results are coming from. 

[PaulLohr]

Are we not supposed to use the same coordinate system as that of the basemap? In Jeremy's post, he said he is using a State Plane coordinate system.

[SharonUngerer_DNREC]

The basemap coordinates don't affect the actual data collected.  The basemap coordinate system has to align with the location profile when working in Field Maps/Collector.  Since the Map Coordinate System of the location profile matches the basemap then it will work.  The location profile doesn't change coordinate system of map or layer.  Just reconciles datum of map and receiver.