Accession Number : ADA134999

Title :   Application of Hierarchical Data Structures to Geographical Information Systems.

Descriptive Note : Contract rept. 29 Jul 82-29 Jun 83 on Phase 2,

Corporate Author : MARYLAND UNIV COLLEGE PARK COMPUTER VISION LAB

Personal Author(s) : Samet,H ; Rosenfeld,A

PDF Url : ADA134999

Report Date : 30 Sep 1983

Pagination or Media Count : 84

Abstract : 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.

Descriptors :   *Digital maps, *Data processing, Topographic maps, Data bases, Programming languages, Data management, Editing, Hierarchies, Data storage systems

Subject Categories : Cartography and Aerial Photography

Distribution Statement : APPROVED FOR PUBLIC RELEASE