|Abstract||The basic imaging geometry of the Synthetic Aperture Radar (SAR) is considered for the study of trail and road detectability in imagery of rainforests with no significant topographic relief. It is shown
that the visibility of these features on SAR images depends mainly on the SAR resolution, trail (or road) widths and their orientation relative to the SAR viewing direction. The results are confirmed experimentally on a dense forest site in the south
of Sumatra, Indonesia, using the multi-resolution capability of Radarsat. The best trail detectability was obtained with the fine modes at the highest incidence angle. The use of the ascending and descending modes is ideal. It permits trail imaging
with different orientation, and as such increases trail detectability. This permits even the detection of 5 to 6 m width trails under particular conditions. The same trails could not be detected using JERS-1 satellite SAR of coarser resolution.