MrSID is a unique compression format for high-definition imagery and visual data, frequently used in geospatial industries. Although MrSID sounds like it may be a person, it’s an acronym for Multi-Resolution Seamless Image Database.
The prototype for MrSID compression technology was developed at Los Alamos National Laboratory in 1992. LizardTech created a subsequent commercial version of the technology that was called the MrSID Generation 2 (MG2) format, which was released in 1998. LizardTech continued to develop and improve the compression technology to provide greater GIS functionality. The latest version of the MrSID file format, MrSID Generation 4 (MG4), was introduced in 2009.
In 2018, LizardTech was brought into the Extensis family, and the MrSID technology is now a part of Extensis’ suite of applications and tools.
SID files can be generated from most file types, including GeoTIFF, Imagine, ECW, and LAS LiDAR files. SID files are compressed, but they preserve the quality and detail of raw imagery and point cloud data. This means that all the convenience of compressed data (easier to share, export, import, and store) can be gained, without the typical lossy image compression issues. MrSID files can be losslessly or lossily compressed — the difference with a MrSID file with lossy compression is that our compression method preserves image quality at high compression ratios — allowing the user to create a visually lossless image at a fraction of the original file size.
SID files also feature a unique attribute for viewing performance. When images are compressed to MrSID format, they are encoded as multiple resolutions of the generated image. This is similar in effect to the trick of creating image “pyramids,” but the MrSID technique does not create extra files for all the pyramid levels nor does it incur the corresponding overhead in storage space. Instead, the resolution levels are inherent in the encoding scheme and fully contained within the single MrSID output file itself. When you view a MrSID file, the file only decodes the resolution level that you need at that exact time.
In addition to enabling requests for only the resolution level desired, MrSID technology offers selective decompression, which allows applications to request and decode only the scene (geographic area) of interest from the file. Some other file formats and compression schemes, by contrast, require the whole image to be decoded even if only a small part is to be shown on the screen.
SID raster files are created using a proprietary, patented, wavelet compression technology.
Extensis’ suite of geospatial imagery tools allows you to open and view MrSID files, as well as create them.
However, through Extensis integration partnerships, MrSID files are supported by many GIS applications. Software packages such as ESRI, ERDAS, ArcGIS, ENVI, and Autodesk can all read SID files. The list continues to grow as Extensis makes Decode Software Development Kits (Decode SDK) available to the public with which developers can enable any application with the capability to read MrSID files.
Extensis also offer a free plugin for Adobe Photoshop. More information and download links available via this link.
The MrSID technology is relatively agnostic about the input file format and can be used with a wide variety of common industry formats that meet specific data type requirements. MrSID files can be generated from formats including GeoTIFF, Imagine, and ECW. New MrSID files can be created using GeoExpress and Portfolio.
MrSID files serve a wide variety of industries that rely on high-definition imagery:
As more industries experience the need for ingesting, editing, sharing, and projecting high-definition imagery, an increasing number of uses are being found for the MrSID file format’s exceptional attributes.