Line Simplification Algorithms

Work on the generalisation of cartographic line data, so that small scale map data can be derived from larger scales, has led to the development of algorithms for a variety of generalisation operations, including line simplification. A major objective when capturing linear digital map data is the creation of accurate representation of naturally occurring lines, using a minimum of processing time and storage. When paper maps are converted into a digital representation using manual digitising methods, one time saving method used is that of stream mode digitising. In stream mode the digitiser samples continuously as the cursor is moved along the manuscript line. Co-ordinate density in stream mode is usually determined by time interval, which can lead to the generation of surplus co-ordinate data. For a number of practical considerations this superfluous data should be eliminated. These considerations include: