Implications of weighting metrics for line generalisation with Visvalingam's algorithm
Visvalingam, Maheswari; Whelan, John C.
Visvalingam algorithm for line generalisation; Mapshaper; Evaluation of weights in use
- © M Visvalingam and J C Whelan, 2014
Visvalingam’s algorithm was designed for caricatural line generalisation. A distinction must be made between the algorithm and its operational definition, which includes the metric used to drive it. When the algorithm was first introduced, it was demonstrated using the concept of the effective area of triangles. It was noted that this metric could be weighted and that alternative metrics could be considered.
The Ordnance Survey (Great Britain) and others are using Visvalingam’s algorithm for generalising coastlines, with a complex parameter-driven function to weight the original metric. However, there is a need for further research. This paper shows how Mapshaper and open source data were used to scrutinize the effects of shape weighting. The paper uses these results to investigate why weighted metrics were used to comment on the range of applicability of weightings to Visvalingam’s algorithm and to reiterate the original guidance provided for the use of weights
- The University of Hull
- Additional notes
- Explorations in digital cartography discussion paper series. Discussion paper; 1 Updated version of the paper published 4/12/14
- 2 MB