Ground Control Points vs. Check Points
While obtained the same exact way, ground control points and check points serve slightly different purposes in our workflow.
A ground control point is used with non RTK drone data. The basic GPS built into the non RTK drones give us a photo geolocation bubble of about 10’ (the actual location of the photo can be up to 10’ off from what it claims) These ground control points are then used to anchor the points in the photos to a highly precise and accurate location on earth. These ground control points are a fundamental piece of the photogrammetry process and are necessary to create an accurate map.
A check point is used with RTK drone data. The highly accurate RTK GPS built into these drones geolocates the photos to less than .1’, so there is no need for “anchors” to be used in the photogrammetry process. Instead, these points serve as checkpoints, or a quick and easy way for us to verify the accuracy on the project after it has processed.
Both ground control points and checkpoints are essential for drone data collection. Without them there is no way to verify accuracy on a project.