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--------------------------------------------------------------------------------- General GIS Topics and Points of Interest ESRI GIS Dictionary GPS - Global Positioning System General GIS Topics and Points of Interest... United States Geological SurveyEnvironmental Systems Research Institute GIS Dictionary of TermsReading Contours on a Map What is the difference's between recreational and professional grade GPS Devices? MrSID (Multi-resolution Seamless Image Database) is an image compressor, viewer, and file format for extremely large raster graphics images. MrSID, created by LizardTech, works by putting together hundreds of small image tiles into one large seamless image that can be compressed and decompressed with little or no degradation. One problem previously associated with raster images was the long amount of time it took to open very large files. The creators of MrSID overcame that problem by giving the user the ability to decompress just the portion of the image they wanted to view. The user can move from one part of the image to another quickly without having to wait for the entire image to decompress. Another problem associated
with massive raster images was the large amount
of storage space they required. MrSID uses a
patented "wavelet" technology first developed at
the National Research Laboratories at Los Alamos
to achieve a compression ratio of 20:1 for The wavelet technology used by
MrSID relies on advanced mathematical
algorithms both to compress an image and
build the
MrSID Viewer (GeoViewer) Screen Shot Showing Color Photography...
MrSID Viewer Screen Shot Showing decades-old DOQQ's
Additional Information: MrSID is a patented, wavelet-based file format designed
to enable portability of massive bit-mapped (raster) images. The format employs
discrete wavelet transformations (DWT) in a seamless fashion on tile subsets of
the image data and stores the wavelet coefficients in a data structure that
supports efficient retrieval of the data needed to generate a specified
rectangular zone of the image at a chosen spatial resolution. The data structure
of a MrSID image is a set of bitplanes designed to support 'transactions' of
image data by extracting and delivering exactly and only those bitplanes
necessary to construct a view according to desired scene, scale, or image
quality, independent of bandwidth constraints. The format was designed to enable
instantaneous viewing and manipulation of imagery both locally and over networks
without sacrificing quality. Excerpt from GIS Department E-Mail Update: I have had a few questions on our new Aerial
Photography. Our recommendation is that if you want to view MrSID imagery
(stand-alone), download and install the Express View Browser Plug-In from
Lizardtech, which can be found here...
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