A Graphical Generalization of Localized Morphological Discontinuities on Medium-Scale State Topographic Maps

摘要

Localized morphological discontinuities are essential features in topographic maps and aid in reading terrain from a map. The present study proposes specific procedures for cartographic generalization of discontinuities on medium-scale topographic maps. Localized morphological discontinuity is defined as a location where the grade of the terrain changes discontinuously. Localized morphological discontinuity is indicated by a contour line which contains small, consecutive lines extending to its right side. Approximately 5% of localized morphological discontinuities do not collide with other elements. After performing our generalization procedures, a significant number of discontinuities conformed with constraints consisting of localized morphological discontinuity parallel to or aligned with other line features (roads, tracks, rivers, or outlines of land-use boundaries). The procedure employs two components: a database and a plugin. The database was implemented in PL/pgSQL and C, and the plugin (ArcGIS Pro plugin) was implemented in C# using.NET . Processing resolved 70% of discontinuities which were in collision. The article discusses various aspects of this generalization procedure.