Cartographic objects in a multi-scale data structure

ABSTRACT GIS need a function to draw sketches quickly and in arbitrary scales. We propose a multi-scale hierarchical spatial model for cartographic data. Objects are stored with increasing detailand can be used to compose a map at a particular scale. This results in a multi-scalecartographic forest when applied to cartographic mapping. The structure of the multi-scaleforest is explained. It is based on a trade-off between storage and computation. Methods toselect cartographic objects for rendering are based on the principle of equal informationdensity. 1. INTRODUCTION Geographic Information Systems manage data with respect to spatial location and those dataare presented graphically as a map or sketch. There are a number of similar graphicsapplications, where a database of entities with some geometric properties is used to renderthese entities graphically for different tasks. Typically these tasks require graphicalrepresentations at different levels of detail, ranging from overview screens to detailed views(Herot