Ground Control Points Archive

Ground Control Points Archive is CompassData's off-the-shelf library of more than 85,000 surveyed, photo-identifiable ground control points (GCPs) across six continents, including clusters at over 1,100 airports. Without accurate ground control, satellite, aerial and drone imagery and LiDAR cannot be tied reliably to real-world coordinates, and commissioning a new field survey adds days of fieldwork, travel and post-processing. Where archived points already cover a site and meet the required accuracy, buyers can use them instead of sending a survey crew.

Each point was surveyed in the field with high-precision, dual-frequency GNSS receivers, post-processed with precise ephemeris corrections and cross-checked against known control networks such as CORS stations, under an ISO 9001:2015-certified quality management system. Points are graded from Quality-0 (0-5 cm horizontal and vertical accuracy) to Quality-4 (50 cm-2.5 m horizontal). Airport points are processed to FAA DO-200A to support image production for aerodromes. For areas that are too remote or restricted for a surveyor, CompassData also produces Remotely Sensed Ground Control Points (RSGCP), derived from synthetic aperture radar (SAR) or imagery products, with RS-1 (≤1 m) or RS-2 (≤3 m) precision.

Buyers explore the archive in an interactive web map, where each point shows its photos, station diagram and accuracy report. Each purchased point comes as a data package: a coordinate file (latitude, longitude, elevation, easting, northing) with metadata, an accuracy report, an image chip, a surveyor's site sketch, field photos in four directions, and Esri Shapefile and Google Earth KMZ files. Typical uses are orthorectification, LiDAR non-vegetated vertical accuracy (NVA) control, positional accuracy checks and repeat mapping of the same site, such as construction monitoring.