Surveying fundamentals can quietly make or break a drone mapping project—and grid vs. ground coordinates are one of those topics that trip people up more often than they expect.
In this episode of Your Drone Questions. Answered the conversation zooms in on the essentials every drone pilot working with mapping, surveying, or lidar data needs to understand.

The discussion is joined by Mark White from Duncan-Parnell, a licensed land surveyor with decades of experience in geospatial training and support. Together, they break down what grid and ground coordinates actually mean, why GPS measurements don’t live on the same “surface” we work on in the real world, and how scale factors quietly affect distances, areas, and deliverables.

You’ll hear clear explanations of state plane systems, ellipsoids, and why mapping on a flat grid is convenient—but not always representative of true ground distances. The episode also tackles site calibration (sometimes called localization), how it works behind the scenes, and why it’s often the key to making drone data line up correctly with survey control.

Useful links:
-TBC Power Hour Defining and Working with Grid and Ground Coordinates (16:09 mark is where the graphic referenced in the podcast is discussed): https://www.youtube.com/watch?v=-3SzLtNWa7E 

-GNSS Site Calibrations in Trimble Access – Everything You Need to Know | Survey Matters (first 2.5 minutes in particular): https://www.youtube.com/watch?v=z5fwa2tGgVA

https://www.youtube.com/@duncanparnellgeospatial

https://www.youtube.com/playlist?list=PLhkUv995xbiWXc9Vz2oGD7jdBD2O1wunK

https://www.duncan-parnell.com/