Adler C. G. da Silva Shin-Ting Wu Preserving Coincidence and Incidence Topologies in Saalfeld’s Polyline Simplification Algorithm. 107-121 2005 conf/geoinfo/2005 GeoInfo http://www.geoinfo.info/geoinfo2005/papers/P64.pdf db/conf/geoinfo/geoinfo2005.html#SilvaW05