Geometric Processing of Ikonos Stereo Imagery for Coastal Mapping Applications

Abstract

Ikonos and other high-resolution commercial satellite imaging systems are used for coastal mapping, monitoring, and change detection. In addition to offering high-resolution and multispectral data, these systems provide a short revisit time (2.9 days) and the capability to perform stereo mapping. This article reports on the photogrammetric mapping of a Lake Erie coastal area from 1-m-resolution Ikonos Geo stereo images. The nominal accuracy of ground point de-termination with vendor-provided Rational Function (RF) coefficients is evaluated; the authors report that systematic errors are found when compared with ground control points. However, a significant improvement in the accuracy is achieved by a refining process that applies a three-dimensional affine transformation to the RF-calculated 3D ground points to correct the systematic errors. A digital elevation model (DEM) is automatically generated and an orthoimage is produced using the DEM and the refined geometric model. Finally, a 3D shoreline is extracted through manual digitization in one image of a stereo pair and then automatic matching in the other image. The authors include a discussion of issues concerning the production of digital tide-coordinated shorelines using instantaneous observations. The authors conclude that high-resolution satellite imagery will come to play a significant role in coastal mapping.