Integrating quantitative and qualitative aspects of digital line simplification
Robert G. Cromley, Gerard M. Campbell · The Cartographic Journal · 1992
Digital line simplification is a common cartographic operator for removing redundant detail from encoded lines due to scale changes or in-stream digitising procedures. In most discussions of line simplification algorithms, it is assumed that the parameters for the simplification, such as the bandwidth or the percentage reduction in objects, have already been determined and are constant. There is rarely any discussion of how parameters are set. In this case, one enters the line simplification problem at the second stage, dealing only with the issue of determining which segments to retain. Although simplification operators exist to eliminate detail as map scale changes, there is little connection between scale and the bandwidth parameter. As scale changes, there are no established guidelines for setting a bandwidth. However, Topfer and Pillewizer's radical law states that the number of objects to be retained in a scale change is proportional to the square root of the scale change. This paper presents a method for combining the quantitative measure of how much detail to retain with a qualtitative measure of which detail to retain in an attempt to produce a better objective method for implementing the subjective rules of manual compilation.