Check Point

Check Point is a surveyed geographic location used to independently evaluate the positional accuracy of GIS, drone mapping, photogrammetry, LiDAR, and remote sensing datasets. Unlike Ground Control Points (GCPs), check points are not used to control or georeference the mapping project. Instead, they are reserved for accuracy assessment after data processing.

In drone surveying and photogrammetry, check points are typically measured using high-accuracy GNSS or RTK/PPK equipment and distributed across the project area. Their known coordinates are compared with the corresponding coordinates extracted from the final orthomosaic, Digital Elevation Model (DEM), Digital Surface Model (DSM), or 3D point cloud. The differences are used to calculate horizontal and vertical errors, RMSE, and overall mapping accuracy.

Check points are essential for quality control in GIS mapping, UAV surveying, aerial imagery, LiDAR processing, cadastral mapping, engineering surveys, and geospatial analysis. Properly distributed check points provide an independent and reliable way to validate whether a geospatial dataset meets project accuracy requirements and industry standards.