Ansoult, MM., Soille, PJ., & Loodts, JA. (1990). Mathematical Morphology - a Tool for Automated Gis Data Acquisition From Scanned Thematic Maps. Photogrammetric Engineering and Remote Sensing, 56(9), 1263-1271. https://hdl.handle.net/2078.5/138249 (Original work published 1990)