What are ground control points used for in remote sensing?

Ground control points (GCPs) are crucial in the field of remote sensing as they serve as reference locations that help in geo-rectifying images. When satellite or aerial images are captured, they may not initially align accurately with real-world geographic coordinates due to various factors such as sensor errors, atmospheric conditions, or distortions from the Earth's surface. GCPs are precisely surveyed points on the ground, and their known geographical coordinates allow for the correction of these discrepancies.

By utilizing GCPs during the processing of images, analysts can ensure that the imagery reflects true locations on the earth's surface. This correction process allows for more accurate mapping, analysis, and integration of remote sensing data into geographic information systems (GIS). As a result, the images become more useful for understanding spatial relationships and making informed decisions based on the data.

While graphical representations of terrains, monitoring vegetation changes, and establishing legal property boundaries are all important aspects of geospatial analysis, they rely on the accuracy provided by properly geo-rectified images, which is fundamentally achieved through the use of ground control points.