A Complete High-Resolution Coastline of Antarctica Extracted from Orthorectified Radarsat SAR Imagery

摘要

A complete, high-resolution coastline of Antarctica, extracted from an orthorectified mosaic of Radarsat-1 synthetic aperture radar (SAR) images through a sequence of automated image processing algorithms, is presented, A locally adaptive thresholding method is used to segment the orthorectified SAR images, while image-object formation and labeling, and edge-tracing techniques are used to process the segmented images into vector-based cartographic products of coastline, defined here as the boundary b etween continental ice or rock exposures and sea ice covered ocean. The absolute accuracy of planimetric positioning of the resultant coastline is estimated to better than 130 m, and its spatial resolution (25 m) is adequate for supporting cartographic a nd scientific applications at 1:50,000 scale. This radar-image-derived coastline gives an accurate description of geometric shape and glaciological characteristics of the Antarctic coasts and also provides a precise benchmark for future change-detection studies.