Hello Mike,
While Collector implements support for this new datum (and possibly epochs in the future (but don't quote me on this)), there is a way to fool the “system” with Arrow and the Datum shift feature we have in Eos Tools Pro.
When connected to your RTK base/network which is referenced to the Nad83 2017.5 datum, the output coordinates of the Arrow will also be in this same datum. This is the reason why Eos Tools Pro is showing you the right coordinates.
At the end, what Collector is expecting from the Arrow is Nad83 2011, and then it goes through the existing on-the-fly datum transformation feature of Collector to match the map in web mercator (which should be WGS84 G1762, and which is ITRF epoch 2005), if you followed the video tutorial on our web site. https://eos-gnss.com/configuring-esri-collector-ios-arrow/
Therefore, using the datum shift feature of Eos Tools Pro (Config menu), you can make the Arrow output in Nad83 2011 and keep the actual config of Collector unchanged. Here is what to do:
1) get a point (any point) in the aera where you'll be working, for which you have coordinates expressed in both Nad83 2011 and 2017.5.
2) convert lat/lon to decimal degrees and keep elevations in meters
3) in Config menu in Eos Tools Pro, activate the offset switch on the top. Enter the "from” and “to” coordinates (this will soon change in the next release to “datum shift”, to avoid confusion with the new laser offset feature we introduced at the UC this year). You want the “from” to be the 2017.5 coordinates set and the “to” to be the 2011 coordinates. Then click on “calculate offset” and save to the receiver.
If you do not have, nor cannot get a sample point from the State authorities who defined this datum, do not panic. 🙂 . Go to the HTDP web site and get a set of coordinates yourself. Here's how:
1) follow the procedure in this document (still from our learning center menu): https://eos-gnss.com/computing-datum-offset-values/ with the following difference:
2) you will need to select input datum to be NAD83 epoch 2010.0 (not 2011.0) and output Nad83 datum to have epoch 2017.5
this way you'll get your pair of coordinates.
Collector should love this output from the Arrow better :-). Once the Collector team implements support for this new Californian datum, I suggest you disable the above and let Collector handle it. At least you have a solution now.
I have assumed you are using iOS. The same is available in Eos Tools Pro for Android, under the Settings menu.
Any issue, please write to us at support@eos-gnss.com
Good luck,
Jean-Yves
Eos Positioning Systems
