Here you can curve fit and surface fit your 2D and 3D data online with
a rich set of error histograms, error plots, curve plots, surface plots,
contour plots, VRML, auto-generated source code, and PDF file output.
If you're looking for quality curve fitting and surface fitting, this is the
site for you! Source code is available at the Google Code Repository.
To begin, select an equation family from the drop-down menus above or try
the "Function Finders" to help determine the best curve fit for your data.