Photogrammetric ground control points (GCPs)

Ground control points (or GCPs) are points on the ground with known coordinates.

In an aerial mapping survey, GCPs are points that the surveyor can precisely pinpoint: with a handful of known coordinates, it’s possible to accurately map large areas. 

The data can be downloaded at www.geoportal.gov.pl in the "data for download" layer group - photogrammetric data - photogrammetric matrix - photopoints