FERRET is an interactive computer visualization and analysis environment designed to meet the needs of oceanographers and meteorologists analyzing large and complex gridded data sets. "Gridded data sets" in the FERRET environment may be multi-dimensional model outputs, gridded data products (e.g. climatologies), singly dimensioned arrays such as time series and profiles, and for certain classes of analysis, scattered n-tuples (optionally, grid-able using an objective analysis procedure provided in FERRET). FERRET accepts data from ASCII and binary files, and from two standardized, self-describing formats. FERRET's gridded variables can be one to four dimensions - usually (but not necessarily) longitude, latitude, depth, and time. The coordinates along each axis may be regularly or irregularly spaced.
FERRET was developed by the Thermal Modeling and Analysis Project at NOAA/PMEL in Seattle to analyze the outputs of its numerical ocean models and compare them with gridded, observational data. Model data sets are often multi-gigabyte in size with mixed 3 and 4-dimensional variables defined on staggered grids. FERRET offers the ability to define new variables interactively as mathematical expressions involving data set variables. Calculations may be applied over arbitrarily shaped regions.
FERRET provides fully documented graphics, data listings, or extractions of data to files with a single command. Without leaving the FERRET environment, graphical output may be customized to produce publication-ready graphics. Animations are also available. FERRET is supported on a variety of Unix worstations with a version also available for Macintosh. A point-and-click interface is under development at the time of this writing. FERRET is available at no charge from anonymous FTP [node abyss.pmel.noaa.gov] or from Mosaic [URL http://www.pmel.noaa.gov/].
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Ferret Users Guide (in text)
Ferret Users Guide (in Postscript)