The synoptic view of Landsat imagery provides a new perspective in archaeology. This is especially significant for large, complex sites such as Angkor, the religious and administrative centre of Khmer dynasts for more than 500 years. In this study the major features of the Angkor townscape
, -barays, temple-pyramids and canals - are examined. Landsat-TM signatures are developed for each class of feature and detectability ratings established. Changes in the urban perimeter are identified and set in a chronological framework. The regional road network is mapped with the addition of new details. The benefits of the Landsat overview are shown to be the discovery of hitherto unrecorded detail, increased understanding of the site situation from contextual environmental relations and an improved comprehension of the historic landscape as a whole.