Application of Hierarchical Data Structures to Geographical Information Systems.
Contract rept. 29 Jul 82-29 Jun 83 on Phase 2,
MARYLAND UNIV COLLEGE PARK COMPUTER VISION LAB
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The purposes of this investigation were twofold 1 to construct a geographic information system based on the quadtree hierarchical data structure, and 2 to gather statistics to allow the evaluation of the usefulness of this approach to geographic information system organization. To accomplish the above objectives, in Phase I of the project a database was built that contained three maps supplied under the terms of the contract. These maps described the flood plain, elevation contours, and language classes of a region in California. The map regions were represented in quadtree form, and algorithms were developed for basic operations on quadtree-represented regions set-theoretic operations, point-in-region determination, region property computation, and submap generation. The efficiency of these algorithms was studied theoretically and experimentally. On Phase II of the project, the following additional tasks were performed a Query Language Design b Database updating c Point and linear feature data construction.
- Cartography and Aerial Photography