Application of Hierarchical Data Structures to Geographical Information Systems.
Abstract
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 landuse 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. In Phase II of the project a quadtree based Geographic Information System was partially implemented, allowing manipulation of images storing area, point and line data. This system included a memory management system to allow manipulation of images too large to fit into main memory, a software package to allow users to edit and update images, database management and map manipulation functions, and an English-like query language with which to access the database. Phase III of this project primarily dealt with enhancements and alteration to this information system package, an evaluation of some of the design decisions, and the collection of empirical results to indicate the utility of the software and to justify the indicated design decisions. Included with this report is a survey of appropriate data structures for future investigation vis-a-vis the current system.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 13, 1984
- Accession Number
- ADA152169
Entities
People
- Azriel Rosenfeld
- H. Samet
Organizations
- University of Maryland