|
Track: Database Design and Automation
William Bamberger
San Diego Data Processing Corp.
5975 Santa Fe Street
San Diego, CA 92109
Telephone: 619-581-9747
Fax: 619-581-9617
E-mail: bbamber@sannet.gov
Derren Duburguet
New Technology for Digital Orthophotography
Defining Issue: Digital orthophotography is becoming a common component of GIS databases. Implementation of largearea (city and regional) digital orthophotography, however, has been difficult due to the numerous large files and the variety of possible image resolutions. New Technology: New technology is now making digital orthophotography easier to use by compressing huge multifile, multiresolution databases into a single file that can be viewed on a personal computer. MrSID (Multi resolution, Seamless, Image Database) is a new cross-platform software technology that compresses large images and image databases. MrSID is based on the discrete wavelet transform (DWT) compression technology created at Los Alamos National Laboratory (by the same team that created the WSQ standard for the FBI for compressing digital fingerprint images). The resulting image database permits viewing at multiple resolutions in a seamless manner. Methodology: The first large-scale implementation of this technology is now
operational in San Diego. MrSID decompression technology, embedded into an ArcView Version 3.0 extension, provides desktop access to a pixel resolution digital orthophoto database for the entire city of San Diego (325 square miles). The entire database--approximately 1,000 files and 12 gigabytes of data before compression--was compressed to 615 megabytes and put on a CD-ROM. This valuable database is now economically available to many users throughout the City of San Diego and can be easily integrated with other GIS data.
|
|
