Raster scanning, processing and plotting of cartographic documents.

The mass digitization of large volumes of cartographic data from analog map formats into viable digital formats is a complex task involving specialised hardware and algorithms. The work comprises: a general introduction to raster digitizing; hardware scanners, notably drum, photodiode, laser beam and video camera devices; automatic line-followers and automatic manual digitising aids. Consideration is given to interfacing digitizing hardware to host computers, and to the interactions between the cartographic document and digitizing such as resolution precision and accuracy. Software processes are detailed, such as scan conversion, cleaning, and feature tagging, vector to raster conversion, line thickening and symbolisation. A range of devices, systems and applications are discussed. A final section looks at future developments.- M.Blakemore