On the quality of the drainage network cartographic representation

Abstract

One of the most important features of topographic maps is the stream network. Its accurate representation is essential for several applications. This work evaluates the quality of the stream network representation of Brazil and Portugal's official topographic maps. These maps were produced using different scales (1:10,000, 1:25,000, and 1:50,000) and methods (photo interpretation and automatic drainage network extraction). The intention of this analysis is to focus on quality data analysis, optimization and reduction of management costs, and the achievement of better planning. To assess the completeness and positional quality, two actions were taken. The first, concerning the completeness assessment, used the methodology proposed by ISO 19157. The second is related to positional quality analysis using the Buffer Overlay Statistical Method. Results show that completeness and positional errors can appear at different locations, intensities, and scales and may promote changes in the extent and direction of mapped watercourses, drainage density, and consequently the size of the watersheds.