What Does the Field “ground_control” in the Metadata Represent?

The field “ground_control” corresponds to the image passing all ground control points.

Responses are a boolean value (true or false), where true corresponds to the image passing all ground control points and false corresponds to the image not able to get enough ground control points, resulting in the image being geometrically unaligned.

A ground control point (GCP) is feature that you can clearly identify in the raw image for which you have a known ground coordinate. They are used in the creation of every image and the accuracy of the product will vary from region to region based on available GCPs.

To ensure the high accuracy of all of our ortho products on a global basis, Planet uses GCPs derived from high resolution satellite and airborne imagery. For most of Earth’s land mass, GCPs are derived from an ALOS 2.5 m resolution basemap. NAIP is used over the continental United States and Landsat 8 is used as a fallback solution over remote polar areas and some small islands.