Large-scale Topographic Web Maps Using Scalable Vector Graphics

With the advent of the Internet, particularly the World Wide Web, the use and demand for online maps has grown very rapidly. Large scale topographic maps from the United States Geological Survey (USGS) at a scale of 1:24,000 have been traditionally distributed in paper form. To make these maps available to a larger number of people, rasterized versions are now available from various sources. Instead of the common raster format presentation, the solution presented here is based on a vector approach using Scalable Vector Graphics (SVG), a relatively new vector format describing vector graphics for the Web. SVG provides many advantages compared to the use of a raster-based presentation, such as the quality of the graphical representation, maintenance, actualization, interactivity, and extensibility through other Web programming languages. The purpose of this research is to propose an optimal and logical structure for a SVG document with a minimal file size that would be universally applicable to all USGS large scale topographic maps while maintaining the graphic quality at a comparable level with maps presented on paper. The study shows that SVG is a promising technology for delivering high quality, fully-vector topographic maps via the Internet, both in terms of graphic quality and interactivity.