Study On Multi-Scale Representation Model Based On R Tree And Petri Net

Scale is a platitude problem of geomorphology. Multi-Scale are one of the important and inside characteristic that is not neglect by the spatial data. Whether spatial data multi-scale representation or automatic cartographic generalization, its core contents is the same, and it is one of the international puzzle for the map data automatic handle and visualization reasonably be faced with the most rich intelligence and the technique challenge, which cause the extensive concern of domestic and international cartology and GIS realm. For satisfying people's need to the different detailed data, browsing automatically from a kind of scale to another scale dynamically and successionally, the research of multi-scale representation of spatial data is stared in the face. This is a huge engineering, and this paper just tries its best that do a bit of its, aim at the multi-scale representation model of spatial data and the data structure. Based of reading and analyzing domestic and international literature and information, from the angle of theories and fulfillment, multi-scale representation of spatial data is researched. The main works and creations are as the following:1. Multi-scale characteristics (spatial, temporal, semantic) and scale theories of spatial data is studied. Reference frame of the scale is defined. The scale dimensions, origin, scale value are included, which are displayed by take arrowhead to beeline and have origin and direction.2. Many applications in multi-scale representation of spatial data from the model of treed (R tree) are introduced. The model of multi-scale representation based on multi-scale R tree is put forward. For reducing excessive span of the scale, two kinds of different expression methods which are multi-scale representation of spatial data of the different scale and the same scale based on multi-scale R tree are adopted, to extend multi-scale layers of spatial data, satisfying multi-scale representation of spatial data. Multi-scale R tree is built. Data structure and the description of the arithmetic are introduced.3. Current numerous research results of the multi-scale data models are snapshot models. For the sake of more accurate describing the realistic world of the different scale, multi-scale representation model of spatial data based on the Petri net is built up, in which place, transition, and arc of a petri net are used for describing state, event of and relations between cartographicentities.4. The model of multi-scale representation based on multi-scale R trees and the Petri net is used. Finally, by making some experiment benefits of this model are analyzed in great detail.