Question
Write a short note on Ground Control Points (GCPs).
Solution
Ground Control Points (GCPs):
GCPs are features of known ground location that can be accurately located both in terms of their image coordinates (column and row numbers) on the distorted image and in terms of their ground coordinates (typically measured from map or estabilished on the ground in terms of latitude and longitude with respect to a particular projection system, say UTM or Polvconic). A leas-square regression analysis is done to interrelated the geometrically correct (map) coordinates and distorted image coordinates. Then, image is worked to have correct geometrical relationship with its corresponding ground situation.
