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We have GPS survey projects all over the country (CONUS and OCONUS) and I am wondering what the best practice is for having to deal with multiple coordinate systems. I can go from WGS84 UTM 18N meters on one project to NAD83 TX SP E feet to multiple others in one day.

We're using GeoXH receivers and here's my current flow:

  1. On one site, I start with GIS source data in say NAD83 NC State Plane feet.
  2. In PFO: Options -> Coord Sys -> set to NAD83 NC SP feet. Import -> select the shapefile and set the coord sys to NAD83 NC SP feet. Open the imp file. Data Transfer -> Send -> Select the file.
  3. Then in TerraSync: Setup -> Coord Sys -> NAD83 NC SP feet. Set the imp as a background file, they collect the data, email it back (or toss the GeoXH on my desk).
  4. Back in PFO, I set the coord sys to whatever their data is in (sometimes it's the same - yay!), transfer, open, diff correct (*question on that later) Export -> set coord system, and back into ArcGIS it goes.

How do I simplify or streamline this workflow?

Would it be better just to reproject the source shapefiles to lat/lon, import and leave PFO and TerraSync in lat/lon, and then reproject in ArcGIS (back to SP or UTM, whatever) to avoid changing the coord sys in PFO and TerraSync back and forth? And is the projection info stored inside the SSF? I know the data only come in as lat/lon from a sat.

It it baffling that what are considered "projects" in PFO do not remember something as essential as the set coordinate system or am I missing a setting?

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I am dealing with a similar issue. Luckily, I don't have multiple sites in different coordinate systems like you. But I think you are on the right track.

Leaving PFO in lat/long (WGS84) seems to simplify things and prevent outdated or double transformations from occurring. SSFs don't store projection info, because they aren't projected; they are in what ESRI calls an Geographic Coordinate System (lat/long). You can more easily manage your transformations in ArcMap, and they get updated with documentation.

This gets even more complicated when, like in my case, your RTK base station is in another coordinate system, and applies a transformation that doesn't get documented. It prevents me from ever being able to display my points accurately relative to my background imagery on the GeoXH in the field.

My solution was to have ground control surveyed on my site that I could use for testing. This will allow you to test the different projection/transformation and correction workflows to isolate where unexpected errors are happening. After extensive testing using this ground control, I settled upon using ArcMap for all transformations and leaving PFO and TerrsSync in Lat/Long.

I'm curious to hear what, if any, progress you have made on your question.

*I am currently looking into the Trimble Positions add-in for ArcMap Desktop to simplify this process a lot more. No more shapefiles! You should check it out; there is a webinar from a month back that is very informative: http://infogeospatial.trimble.com/2016-10-05UsingTrimblePositionstointegrateTerraSyncwithArcGIS_Take2_RecordedWebinarRegistrationPage_1.html

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