“The MAPEDIT System for Automatic Map Digitization” by Holmes, Austin and Benson

  • ©Harvard H. Holmes, Donald M. Austin, and W. H. Benson




    The MAPEDIT System for Automatic Map Digitization



    A system for the automatic digitization of polygon boundaries is described. Digitized map files are created from a driver tape containing identification codes and approximate centroids of polygonal boundaries (e.g., census tracts), and a film image of the map. The digitizer scans on the film plane in an automatic line-following mode, producing the first stage of the map file for the editing system. The MAPEDIT system, which can be used either interactively or in batch mode, reads maps in several standard formats and provides for combining and selecting maps by census (or other) geocodes or by longitude and latitude. This system provides several stages of data compression, analysis, and verification, including algorithms for detecting straight lines, finding corners, fitting insets of maps together and matching boundaries common to a pair of polygons. Auxiliary programs (1) provide a very high resolution (1 part in 25,000) C.R.T. plot of the map, (2) allow a detailed examination and editing of the map and (3) supply missing geocodes using auxiliary tapes such as the Medlist tapes.

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