Ground control points (GCPs) can be used when working with satellite, aerial, or LiDAR imagery. Using GCPs improves the accuracy of your product and brings the additional value of ground truth by tying your data to an actual earth location. Introducing, GCPs into the orthorectification process can result in sub-meter accuracy, increasing the quality and value of the final product.
To see the distribution of our global archive have a look at the continuously updated map above or download the entire archive as a kml file below. The coordinates of the points are truncated but you can judge the quality of the points. All the archive points come with relevant metadata (photos of the point, station diagrams & accuracy reports). Just zoom and click on the individual points when browsing.
|Quality||Horizontal accuracy||Vertical accuracy|
|1||1 - 10 cm||1 - 10 cm|
|2||10 - 20 cm||10 - 20 cm|
|3||20 - 50 cm||20 - 75 cm|
|4||50 - 70 cm||75 - 125 cm|
|5||70 - 250 cm||125 - 500 cm|
Points can be delivered in any datum or projection required, including WGS84 (G1150) (World Geographic System), ITRF2000, ITRF2008, NAD83, ETRF89 with geographical coordinates in Latitude / Longitude or projections like UTM, Lambert, and Gauss with standard elevations as height above Sea Level or Height Above Ellipsoid (HAE).