Field Maps App Profile Setup not working with custom basemap

Question

I have a web map using a custom basemap which is an image service.  The image service coordinate system is NAD 1983 Rhode Island State Plane Feet (EPSG 3438).  The coordinate system of this image service is not something I have access to alter as it is provided by a different organization.

The web map contains several other hosted feature layers from an Enterprise Portal which are also in NAD 1983 Rhode Island State Plane Feet.  I've double/triple checked to make sure all layers in the web map are NAD 1983 Rhode Island State Plane Feet to match the custom basemap.

I wish to use this web map in the Field Maps App to collect high accuracy data from an external GPS.  The external GPS is setup to receive location data from an NTRIP base station, documented simply as being in "NAD 83 (2011) (Epoch 2010.00).  No wkid is provided.

In the Field Map App I've tried several times to create a profile that will perform a transformation successfully.  I select:

* GCS NAD 1983 2011 (wkid 6318) as the GNSS coordinate system* this seems to be the only relevant choice

* NAD 1983 State Plane Rhode Island FIPS 3800 Feet (wkid 3438) as the Map Coordinate System* I know this is correct
* This is a projected coordinate system

* I zoom in on the State of Rhode Island where my data will be collected using the "Area for data collection" map
* I select the 1st datum transformation provided in the list of options that appears which reads "WGS_1984_(ITRF00)_To_NAD_1983_2011+WGS_1984_(ITRF00)_To_NAD_1983"* I have tried others although based on the documentation, the first is supposedly the best

* I set this as the profile in the Field Maps App

In all cases, no matter which datum transformation I select from the list, when I open the map in the Field Maps app there is an error - "Unable to open.  This map uses a different coordinate system than the current location profile".

Going back to the Default profile (which as I understand it is reading everything in GCS WGS 1984) allows me to open the Map without an error message, and I can collect data.  However, the concern is it is not being collected with the accuracy of the external device.

Hoping someone can help me determine where I am going wrong.  Perhaps I do not need a transformation, but everything I have read seems to indicate I should not be using the Default profile and that I should be "telling" the Field Maps app that the web map I am opening is not in WGS 1984.

Thank you for any assistance.

PaulLohr · Answer

Have you tried WKID 6318 for GNSS Coordinate System in  the Field Maps Location Profile? It corresponds to NAD 1983 / 2011 (unprojected). I don't know how to address MYCS2. NY DOT might be able to help with MYCS2.

WKID 2261 for your map coordinate system in Field Map Location Profile? That would be "NAD 1983 State Plane New York Central FIPS 3102 feet". This needs to match the coordinate system of your published map. This coordinate system uses the original realization of NAD 1983, which is 1986. Might want to check to be sure your map data actually uses the 1986 realization of NAD 1983.

I would think NAD 1983 (2011) (EPOCH:2010) would be correct for TMM GNSS output. But again, I don't know about MYCS2.

GNSS source reference frame in TMM NTRIP setting might use the same as above: NAD 1983 (2011) (EPOCH:2010). But again, I don't know about MYCS2.

Make sure to get some check points against NGS monuments or similar before calling it good.

AngelHinickle · Answer

Hi,

I'm having the exact same issue. We're using a Trimble R2 (survey grade) and connecting into the DOT CORs for corrections. We're using a Trimble TDC6 with Field Maps. The CORS datum is NAD83 (2011) EPOCH 2010 MYCS2. My data layers that I've upload as a web map to ArcGIS Pro are NAD 1983 State Plane New York Central FIPS 3102 feet. I'm having a heck of a time trying to figure out what profile I set up to make this work. If I go with the default, which is WGS 1984 my data will show, but I know that's not correct and won't get accuracy.

My Trimble Mobile Manager is set up for CNSS Correction Source: custom local, server NTrip. We entered all the Ntrip settings and the R2 connects perfect and gets good accuracy. We have the output as "auto" and the geoid as GeOID18 (conus).

Any guidance would be appreciate.

PaulLohr · Answer

You're welcome.

I don't think changing the WKID to one that doesn't match that of the ImageServer service will work. You could try it though.

If the aerials actually use WKID 3438 (rather than 3857 / 102100), the imageServer service could have its coordinate system changed (data frame) then recreate the service. Chances are those aerials use State Plane coordinates (rather than WGS 1984 Web Mercator; WKID 3857 / 102100). You may need to remove and re-add the basemap to force the change. The key is to get that WKID to change to 3438 in the JSON code.