GPS control for 1:50,000-scale topographic mapping from satellite images

Abstract

Ortho-images from digital SPOT satellite data were generated to test their application in production and updating of 1:50,000-scale Canadian National Topographic Maps. The orbital parameters were modeled with Ground Control Points (GCP), and the transformation between image and geographic coordinates was defined. Successful production and update of digital map files, or GIS feature extraction from base images, requires knowledge of the total error budget in the ortho-image process. The errors were found to include the GCP geographic position error, the pointing error for GCPs in image coordinates, DEM error, and transformation and resampling errors.