TPC 2026 - Using GPS/GNSS with Surveys

Using GPS/GNSS with Surveys

TPC makes it easy to use GPS/GNSS data with existing surveys, regardless of whether or not that survey matches the CRS used by the GPS/GNSS data.

This topic will help you understand how this works and look at three options in particular

1.Using the GPS/GNSS CRS for everything

2.Using an existing survey's CRS

3.Converting an existing survey to the GPS/GNSS CRS

Using the GPS/GNSS CRS

With TPC, a survey can use the same CRS your GPS/GNSS uses. Just match your survey's CRS to the one used by your GPS/GNSS equipment. See Coordinate Reference System and Geoids. See Using the GPS/GNSS CRS.

With this option, sharing GPS/GNSS data with your survey involves just importing and exporting data without any calibrations.

Using an Existing Survey's CRS

If you start with a survey in local (like 5000/5000) / State Plane / UTM coordinates that don't match your GPS/GNSS CRS, and you want to keep the survey where it is plus use GPS/GNSS, you can. See Calibrating GPS/GNSS to Your Survey.

Site Calibration

TPC's Site Calibration lets you easily work with GPS/GNSS in your survey. GPS/GNSS geodetic positions are automatically calibrated to your survey's CRS and any survey points export out to GPS/GNSS are automatically reverse calibrated back to the BPS/GNSS CRS.

Converting an Existing Survey to the GPS/GNSS CRS

TPC can also convert your local (like 5000/5000) / State Plane / UTM survey to the CRS used by your GPS/GNSS equipment, as if you had started with that CRS. Now everything is on the GPS/GNSS CRS. See Calibrating Your Survey to GPS/GNSS and Converting an Existing Survey to GPS/GNSS.

This features has been expanded in TPC 2023 R1 (July 2023) to include raw data and drawings. In addition, it removes any calibration reference, so your existing survey actually adopts the GPS/GNSS CRS as if it had originally been created there.

Calibrating GPS/GNSS and an Existing Survey

The option you choose, may require you to calibrate your GPS/GNSS data. TPC includes work flows that simplify how to do the calibration you want. Collecting GPS/GNSS data in the field for two or more of your survey points is all you need.

See Calibrating GPS/GNSS Data.

Grid vs Ground

The CRS you end up using will affect how you work with grid vs ground coordinates. TPC has tools to help you work efficiently with both grid and ground.

Cartesian Grid

It is not uncommon to work with a survey as if it is at ground, even if it uses a State Plane or UTM CRS. These surveys can be referred to as Site or Ground surveys that use Cartesian grid coordinates with no distance or angle corrections.

Low Distortion Projection

If your GPS/GNSS CRS is a low distortion projection, like those used by a county or other small geographical area, you may choose to consider working with Cartesian grid coordinates with no distance or angle corrections as appropriate.

State Plane or UTM

For Coordinate Reference Systems like State Plane and UTM, grid coordinates and distance are not the same as ground coordinates and distances. Again, TPC has all the tools to help you work efficiently with these differences.