Impact of no GCP on elevation extraction from WorldView stereo data

A hybrid model based on 3D deterministic Toutin’s model developed at the Canada Centre for Remote Sensing and taking full advantages of the image metadata was used to geometrically process WorldView-1 and -2 stereo images without in situ ground control points (GCPs) collection. Elevations were thus extracted and compared to 0.2-m accurate lidar elevation data to see the impact of no-GCP. Elevations linear errors with 68% confidence level (LE68) computed over bare surfaces were 2.6 m and 2.1 m for WorldView-1 and -2, respectively with small biases. The not-significant difference in LE68 (around 10–20 cm), when compared to the solution using accurate GCPs, will offer strong advantages of no-control collection in operational conditions, mainly in remote and harsh environments or when cartographic or ground control data do not exist.