Information extraction from images of paper-based maps

The design of a system to extract information automatically from paper-based maps and answer queries related to spatial features and structure of geographic data is considered. The foundation of such a system is a set of image-analysis algorithms for extracting spatial features. Efficient algorithms to detect symbols, identify and track various types of lines, follow closed contours, compute distances, find shortest paths, etc. from simplified map images have been developed. A query processor analyzes the queries presented by the user in a predefined syntax, controls the operation of the image processing algorithms, and interacts with the user. The query processor is written in Lisp and calls image-analysis routines written in Fortran