Background Understanding;
Our AGOL Feature Layer is in NAD83 Zone 17 CSRS (epsg:2958) as well as our correction service (NTRIP) is provided using a Trimble R2. I am assuming that Collector and all AGOL webmaps are in the SRS Web Mercator (epsg:3857)
We also know datum Transformations introduce error.
In Canada, certain Datum Transformation regarding NAD83 Zone 17 CSRS (epsg:2958) are unavailable in Collector (as I understand it, due to IP rights of some organization) so that leaves me using a Default Location Profile in Collector. So what is exactly happening? Is the value of having the high-accurate GNSS connected diminished?
My Question(s);
My end goal is to build a SQL point database with the GIS accuracy (7cm-30cm) in the NAD83 Zone 17 CSRS (epsg:2958) system. When I export my AGOL Feature Layer to shape/GDB I see that the .prj is still in NAD83 Zone 17 CSRS (epsg:2958). Can I assume the 7cm accuracy is maintained through this download process (R2 with Corrections > Collector > AGOL > Export > GDB)?
Also, the data collectors will be using Collector to navigate back to a location in an emergency valve shut-off scenario.
I understand that placing the Collected Data on an AGOL webmap may have an undesirable shift (due to a default location profile), as even the best transformation model will introduce centimetres or metres of error. Therefore, isn’t the 7cm-30cm just washed away during a transformation onto a webmap? As an example: NAD83_1983_To_WGS_1984_1 provides 4m of accuracy (https://support.esri.com/en/technical-article/000005929)
So I suppose my questions in a nutshell would be;
I plan on observing a few benchmarks to know for sure but am looking for a bit of explanation on this from the pros.
Thanks for anything you can offer.