Contour and Vector Plots

Hi again,

    >> Yes, I had the thought that using C for the algorithm would be
    >> easier as well. There are actually some very well-written
    >> marching squares contouring algorithms in C already out there.
    >> I will try to find such an implementation and point you to it
    >> or send you the source code.
    > Thanks, that would be helpful. In my search I didn't come
    > across many. Keep in mind the license needs to be
    > compatible with that of matplotlib.

Of course, in addition to the license, there is the patent issue. I
believe marching squares is patented. I know marching cubes is.,710,876.WKU.&OS=PN/4,710,876&RS=PN/4,710,876

I checked the header of vtkMarchingSquares.cxx which states

  Program: Visualization Toolkit
  Module: $RCSfile: vtkMarchingSquares.cxx,v $

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or for details.

     "System and Method for the Display of Surface Structures Contained
     Within the Interior Region of a Solid Body".
     Application of this software for commercial purposes requires
     a license grant from GE. Contact:

but the patent number they reference which is linked above begins with

  A method and apparatus for displaying *three dimensional surface
  images* includes the utilization of a case table for rapid retrieval
  of surface approximation information.

emphasis mine. So I don't know for sure what the patent status of the
2D algorithm is.