- The Hough transform is an established tool for discovering linear features in images. The present investigation presents a new and specific algorithm for detecting geological lineaments in satellite images and scanned aerial photographs which incorporates the Hough transform, a new kind of a "directional detector," and a special counting mechanism for detecting peaks in the Hough plane. Three test sites representing different geological environments and remote sensing altitudes were selected. The first site represents sedimentary conditions of chalk beds on cherry picker photography; the second represents plutonic conditions of granite rocks on an aerial photograph; and the third represents tectonic fractures of carbonates, chalks, and cherts on digital satellite data. In all cases, automatic extraction and mapping of lineaments conformed well to interpretation of lineaments by human performance.