Accordingly, results are not contaminated by conventional difficulties in conjugate image identification. In addition, the photogrammetric system was calibrated under operational circumstances. These circumstances produced exceptionally good results approaching those predicted by theoretical extrapolations. Results indicate that excellent accuracies are possible based on airborne-GPS controlled strips of photography. The added requirement, when using strips compared to blocks, is the need for at least one imaged ground control point.
Additional points are necessary only for check purposes.
This added point, if provided with orthometric elevation, should be sufficient to transform the ellipsoidal height to its orthometric equivalent. It is recommended that those concerned with surveying and mapping for transportation systems explore the adoption of airborne-GPS methods as a primary tool for providing control to meet their topographic mapping requirements.