Ferret V5.0 Release Notes

New capabilities

Minor Enhancements

Bug Fixes

Known Bugs

New Capabilities

• Ability to access remote Internet data sets
  • Using DODS, the Distributed Oceanagraphic Data System, users have the ability to access data from anywhere on the internet using Ferret. Employing technology similar to that used by the World Wide Web, DODS and Ferret create a powerful tool for the retrieval, sampling, analyzing and displaying of datasets
  • Descripton
  • Demonstration
    
• External Functions Capability
  • User-written Fortran subroutines are used on the Ferret command line just as Ferret internal functions are used. Once defined, these functions operate on arguments defined in a Ferret session and can be plotted, used in expressions, etc.
  • Ferret External functions are compiled individually as shared object files and are dynamically linked with Ferret at run time.
  • Example external functions are available including sorting, gridding data, FFT's and simple template examples for developers.
  • Description
    
• Ability to grid scattered data
  • External Functions give a choice of two gridding algorithms to put scattered (x,y,f(x,y)) or (x,z,f(x,z)) data triples on a Ferret grid.
  • Demonstration
    
• Filled polygons
  
• Support for patterns in FILL, SHADE and POLYGON plots
  
• Greatly enhanced map projection facilities
  • Map projections can now make use of the full range of Ferret graphics with 3-argument versions of the CONTOUR and VECTOR commands. In addition, the /NOAXIS qualifier on SHADE, FILL, CONTOUR and VECTOR and the mp_aspect.jnl script simplify the creation of output graphics.
    
• Visualization techniques for Langrangian data
• Improved binary file access
  • Files with binary data are read faster.
  • Files with binary data can contain different data types (i.e. INTEGER*2, REAL*8).
  • Binary files can contain big-endian or little-endian data.
  • Description
  • Demonstration
    
• WebFerret
  • WebFerret is a collection of Perl and Java programs that allow you to access Ferret with your Web browser. Users can log in to WebFerret (using Unix accounts), and use the full functionality of Ferret from remote locations.
    
• New functions for sorting and sampling data
  • External functions create a list of the indices of data sorted along a given axis.
  • A second set of functions sample data along an axis using a list of indices, which can be from a sort operation or any set of indices.
  • Demonstration
    
• FFT functions
  • External Functions are available to compute FFT amplitude spectra and phase.
  • Demonstration
    
• External function writes data from a Ferret session to a Vis5D formatted file
  • Description
  • Demonstration
    
• New "{1,3,5}" syntax to quickly enter lists of constants
  • Description
  • Demonstration
    
• Easy ways to define custom climatological axes
  • It is now simple to evaluate (say) the climatological average temperature between March 17 and June 23 or to obtain a time series of yearly average temperature between two dates.
  • Description
    
• New documentation on the use of non-gridded data sets
  • With the new capabilities for gridding scattered data, sorting, and sampling comes increased ability to merge gridded and non-gridded data into calculations and visualizations.
  • Description
    
• New functions XSEQUENCE, YSEQUENCE, ZSEQUENCE, and TSEQUENCE provide easy control over the orientation of 1D variables
  • Description
    
• More robust reading of netCDF files
  • Files with invalid coordinate axes
  • Files with case-sensitive, restricted, or "illegal" variable names
  • Files with very long irregular time axes
  • Files with permuted axis ordering
  • Files with decreasing-ordered (reversed) coordinate axes
  • Added a check for NaN when reading netCDF files
    
    

Minor Enhancements

• Improved memory cache hit rate
  • Previous to version 5.0 , when a request was made for data (with a LIST, CONTOUR, PLOT, ... command) and the region of interest on one or more axis of the request was unspecified, Ferret would often fail to reuse previously computed results in its memory cache. This behavior has been improved, so that cache hits occur in almost all possible cases.
  • Description
    
• Simplified memory management control
  • MODE DESPERATE is set automatically
  • Description
    
• SHOW AXIS can be used to view coordinates
  • Previously an axis had to be embedded in a grid to view its coordinates
  • Description
    
• New command alias PAUSE
  • Description
    
• UNRAVEL function renamed
  • The UNRAVEL function has been renamed to XSEQUENCE
    
• The grid of an abstract expression (e.g. "SIN(Y[y=0:45:5]") has changed
  • Description
    
• String arguments to functions
  • External Functions may take arguments which are strings.
  • Description
    
• Maximum string lengths increased
  • GIF output file names to 255 characters
    
• /QUIET argument added to the LIST command
  • Suppresses the displaying of the "LISTing to file XXX.XXX" message
• Added new units gregorian_year (365.2425 days/year), year366 (366 days/year), and year360 (360 days/year) for the "DEFINE AXIS/units=" command.

Bug Fixes

• Ferret is now Y2K compliant
• Normal Axes are now indicated with a "..." rather than a "1:1" using the SHOW DATA command
• Lengths for file variable names and axis names have been increased
• Allow data sets which begin with a digit to work in the [d=dset_name] syntax
• Fixed failure to do a double precision comparison when appending a new output time to an existing netCDF file
• Fixed crash when using /d in the definition of a data set independent variable
• Fixed erroneous error trap for single character replacement symbol
• The previous mp_mercator.jnl script incorrectly used LOG instead of LN in the equations.

Known Bugs

1 May 1999