Hi Layne,

Welcome to the MGIS Community!

I am the Product Manager for Pathfinder Office - Geodetics are a very challenging area for a lot of people, but from the information you have provided here I believe I can help. Would it be alright if I contact you via email and we can get into a bit more detail?

Thanks

------------------------------
Hamish MacMillan
TerraFlex Product Manager
------------------------------

Hello There

I am a brand new participant in this Community and I would consider myself a pretty green noob to Pathfinder Office (v5.85) even though it has been installed on my computer for years.  Let me give you the basics:

1. I have been in the GIS field (currently using ESRI ArcGIS Desktop v10.7.1 and ArcGIS Pro v3.03) for over 20 years; however, have not really ever needed to deal with vertical coordinate system (VCS) &\or changes to them.  I have used DEMs and LiDAR products within the ESRI world but never worried about how the elevation was produced\calculated - everything done, was based on these input datasets.
2. My ONLY use for Trimble Pathfinder Office is to differentially correct Ground Control Points (GCPs) for our drone flights.  Again for the most part, not really worried much about where the elevations are coming from as the produced contours and DEMs from the flight's data are used to evaluate surface water flow for a particular project area.
3. With guidance from a fellow staffer who is the Project Leader for the Geodetic Control Unit within our company, I have been simply exporting my differentially corrected data out as WGS 1984 with EGM96 as the VCS.  This was the advice given to me years ago to be easy and consistent.
4. We utilize a sub-meter (10-cm) virtual RTK broadcast network (Can-Net: vrs.can-net.ca/default.aspx) when collecting GCPs using our Geo7x.  I use TPO to connect to the same network for any PPK work that I have to conduct.

Now for the specifics:

1. This year, I have been asked to compare elevations from an AutoCAD drawing (produced in May 2010) to elevations collected this year using our DJI drone (Mavic 3 Enterprise) and ESRI's Drone2Map (v2023.1.1) software to determine if and how much overburden has been brought on-site.  My calculations will be used to either impose fines or in a remediation order directing the company to either add\remove overburden.  My question is not on how to use either my drone nor my ESRI software - though I would welcome any conversation here as well.  I cannot determine the projection information used in the creation of the 2010 contours.  Through conversations with my colleagues (both of them much more adept to VCSs than myself), they have suggested the most likely coordinate systems used in 2010 were likely NAD83 CSRS v2 (EPSG:8235) and CGVD28 (EPSG:5713).  So using my ESRI tools, I digitized these contours and created a raster surface in the prescribed coordinate systems - after having to upgrade my ESRI installation to include some additional coordinate system transformations.
2. Here is where I am running into problems.  Our Can-Net connection is producing\broadcasting its corrections in NAD83 CSRS epoch 1997(which I'm being told is v2) ; however, I cannot seem to find that coordinate system in TPO - either on the incoming side (to visualize my SSF\COR files) or on the exported side as an ESRI shapefile.
3. I have also gotten my hands on a couple of LiDAR surface for comparison and after projection, these ae not consistent with either my CAD contour elevations nor my drone contour elevations.
4. What I would like to do is to create a consistent workflow with clearly defined coordinate systems from collection through PPK to export that my troubled and poorly informed geodetic mind can follow.

Sadly my Cansel (Can-Net) contacts are not helping me out with this issue.  I would hugely appreciate ANY advice or suggestions that this group can provide.  I'm even willing (quite happily) to take this conversation offline into email &\or telephone should that be easier.

Layne Seely

------------------------------
Layne Seely
------------------------------