Ground Control Points (GCPs) provide a more accurate geospatial reference for your mission. GCPs are typically collected with a survey grade GPS receiver and marked on the ground using a large, easy to recognize symbol such as an ‘X’ or chevron.
To reference your mission with GCPs, you must provide Event 38 by e-mail with a text file containing labels, latitude, longitude and altitude in WGS84 and meters respectively. Information may be provided in other reference systems for an additional fee, please contact us for details. Be sure to include a header row that labels each column, as in the example below.
1,41.036167322,-81.530095353,262.8796,corner of parking lot
2,41.036166210,-81.529944057,260.8028,end of treeline
If your images aren’t geotagged or if geotags are known to be of poor quality, each GCP will need to be located visually. If this is the case, please also provide a short description of the location using landmarks visible from the air.