What is MrSID?

MrSID is an acronym for Multi-resolution Seamless Image Database, a powerful wavelet-based image compressor, viewer and file format for massive raster images that enables instantaneous viewing and manipulation of images locally and over networks while maintaining maximum image quality. Features include unprecedented compression ratios while maintaining highest image quality, true multiple resolutions, selective decompression, seamless mosaicking and browsing.

Does GIS software support MrSID?

Yes! Most importantly, as far as MassGIS is concerned, the MrSID Portable Image Format integrates seamlessly with today's most popular GIS software from ESRI, Intergraph, ERDAS, MapInfo, Bentley, Autodesk, and others.

How is MassGIS using MrSID?

MassGIS has taken advantage of the MrSID technology by converting all of its 1:5,000 Color Ortho Images, 1:5,000 Black and White Digital Orthophotos, Scanned USGS Quads, Coastal Color Orthophotos, NOAA Nautical Charts, and Forested Land Cover images in TIFF format to the .sid format (with .sdw header files for georeferencing). The aim in the conversion is twofold: to decrease download time for ftp transfer of imagery, and to allow a greater number of files to be packaged on compact disc. With the MrSID Publisher software, for example, MassGIS achieved compression ratios of 15:1 for half-meter black and white orthos, 10:1 compression for 1-meter black and white orthos and scanned quads, and 20:1 compression for color orthophotos. In terms of file size, for example, this means that an original half-meter orthophoto at 64 megabytes is now available at about 4.5 megabytes, with very little loss in image quality. Further, MrSID takes a 16mb one-meter tiff file and produces the .sid version at about 1 megabyte.

Go to the Download Image Data page to download MassGIS imagery in MrSID format. The MassGIS Data Viewer allows for display of MrSID imagery, including the Runtime version.

Note that in order for ESRI's ArcView 3.x software to recognize some newer MrSID images as valid .sid files, users may need to download and install the latest AVMrSID.dll from http://www.lizardtech.com/download/dl_download.php?detail=geo_avmrsid_dll&platform=win.

How can I get more information on MrSID?

MrSID technology is patented and developed by LizardTech, Inc. of Seattle. For more information on MrSID visit the LizardTech web site at http://www.lizardtech.com. The site includes a free, downloadable browser plug-in and trial viewer software for displaying any MrSID image, including those available from MassGIS.

Last Updated 5/24/2005
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