Scan-Line Methods in Spatial Data Systems

摘要

This paper examines a method of manipulating data in grid cell spatial data management systems such as Geographic Information Systems (GIS) and digital cartographic systems. While scan line methods have advantages when used only in traditional GIS operations such as manipulation of region polygons (binary overlays), much of this paper discusses digital imagery, digitized map backgrounds, and other types of 'pictorial' or multibit data. This is because the integration of these kinds of data with GIS will become more prevalent and because scan-line techniques are especially useful for pictorial data. The incorporation of remote sensing data into GIS is a major current issue. Jensen notes that 'The full potential of remote sensing and GIS can best be achieved if the technologies are integrated. Remote sensing data consists mostly of digitized photography, so it is important to be able to handle photographic data in a GIS. Modern digital cartography entails the handling of ever-larger data sets. And it may take many of these data sets to cover a region of interest. This amount of data cannot be handled well on present computer systems, and extrapolation of computer capabilities shows that handling large amounts of data will be difficult for many years to come.