Marching Squares Algorithm

Some more possible contour generating code links:

    [1] http://www.geog.uni-hannover.de/grass/
    [2] http://www.triplexware.huckfinn.de/geogfix.html
    [3] http://www.triplexware.huckfinn.de/contweber.html
    [4] http://astronomy.swin.edu.au/~pbourke/projection/conrec/
    [5] http://members.bellatlantic.net/~vze2vrva/

Hi Gary, thanks for the tips. Note that [1] appears to be GPLd and
we're looking for a routine with licenses as permissive as the
PSF/matplotlib license. I believe [2] and [4] are both pointing to
the same algorithm, by Paul Bourke - this one has a C++ implementation
that includes the following license restriction

  Additionally, the authors grant permission to modify this software
  and its documentation for any purpose, provided that such
  modifications are not distributed without the explicit consent of
  the authors and that existing copyright notices are retained in all
  copies. Some of the algorithms implemented by this software are
  patented, observe all applicable patent law.

Since this code implements the Bourke algorithm, I assume the other
implementations have the same patent restrictions, but I haven't taken
a close look.

[3] is released under the MPL -
http://www.mozilla.org/MPL/MPL-1.1.html, which as I understand has a
complex licensing history - it certainly takes a lawyer to read
through it - I'm not sure what the status is.

[5] is certainly as possibility, if as you say, we contact the author
and see if he is willing to release it to us.

Hopefully, all of this is moot, as I understand that STSci has been
working on a routine ripped from gist and Perry says they are close to
having a prototype. I still think it's worthwhile investigating
whether marching squares is patented or enforceable - Mr Horton's
response was not terribly enlightening.

JDH

True, I didn't pay much attention to licencing. In light of it though, here
are a couple more links to a couple of gentlemen who may be worth
grovelling to should the need arise. No specific licencing is mentioned.

<http://mahi.ucsd.edu/parker/Software/>

The documentation says the contouring code was written by this guy who is
the director of the SETI@...168... project:

<http://setiweb.ssl.berkeley.edu/~davea/resume.html>

regards,
Gary

*********** REPLY SEPARATOR ***********

···

On 28/10/2004 at 09:25 John Hunter wrote:

    > Some more possible contour generating code links:

    [1] http://www.geog.uni-hannover.de/grass/
    [2] http://www.triplexware.huckfinn.de/geogfix.html
    [3] http://www.triplexware.huckfinn.de/contweber.html
    [4] http://astronomy.swin.edu.au/~pbourke/projection/conrec/
    [5] http://members.bellatlantic.net/~vze2vrva/

Hi Gary, thanks for the tips. Note that [1] appears to be GPLd and
we're looking for a routine with licenses as permissive as the
PSF/matplotlib license. I believe [2] and [4] are both pointing to
the same algorithm, by Paul Bourke - this one has a C++ implementation
that includes the following license restriction

  Additionally, the authors grant permission to modify this software
  and its documentation for any purpose, provided that such
  modifications are not distributed without the explicit consent of
  the authors and that existing copyright notices are retained in all
  copies. Some of the algorithms implemented by this software are
  patented, observe all applicable patent law.

Since this code implements the Bourke algorithm, I assume the other
implementations have the same patent restrictions, but I haven't taken
a close look.

[3] is released under the MPL -
http://www.mozilla.org/MPL/MPL-1.1.html, which as I understand has a
complex licensing history - it certainly takes a lawyer to read
through it - I'm not sure what the status is.

[5] is certainly as possibility, if as you say, we contact the author
and see if he is willing to release it to us.

Hopefully, all of this is moot, as I understand that STSci has been
working on a routine ripped from gist and Perry says they are close to
having a prototype. I still think it's worthwhile investigating
whether marching squares is patented or enforceable - Mr Horton's
response was not terribly enlightening.

JDH

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------------------------------------
Gary Ruben gruben@...1...
<http://users.bigpond.net.au/gazzar>

gary ruben wrote:

True, I didn't pay much attention to licencing. In light of it though, here
are a couple more links to a couple of gentlemen who may be worth
grovelling to should the need arise. No specific licencing is mentioned.

<http://mahi.ucsd.edu/parker/Software/>

I know Bob. I'll ask him.

···

--
Robert Kern
rkern@...170...

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter

gary ruben wrote:

True, I didn't pay much attention to licencing. In light of it though, here
are a couple more links to a couple of gentlemen who may be worth
grovelling to should the need arise. No specific licencing is mentioned.

<http://mahi.ucsd.edu/parker/Software/>

Actually, having seen this code and the gist code, I'd recommend waiting for the gist-derived prototype.

To muddy the waters a bit, the gist contouring algorithm looks to my eye like Paul Bourke's CONREC algorithm, which may or may not be patented.

O software patents, how I hate thee!

···

--
Robert Kern
rkern@...170...

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter

Which gist contouring routine are you referring to? It appears to use two separate
implementations for different contour functions. We are using the code in gcntr.c.
If that is based on Bourke's routine, there shouldn't be a problem. None of the code
that uses it makes any reference to a patent; there appear to be a number of other
implementations, none of which appear to have been challenged. As far as patent
rights go, aren't they only good for 17 years? It was published in July 1987
(though I suppose it may derive from when it was granted, not published).
Then there is copyright, but that doesn't guard against reimplementation so
long as code isn't copied (But I am not a lawy...).

Perry

···

On Oct 28, 2004, at 4:58 PM, Robert Kern wrote:

gary ruben wrote:

True, I didn't pay much attention to licencing. In light of it though, here
are a couple more links to a couple of gentlemen who may be worth
grovelling to should the need arise. No specific licencing is mentioned.
<http://mahi.ucsd.edu/parker/Software/>

Actually, having seen this code and the gist code, I'd recommend waiting for the gist-derived prototype.

To muddy the waters a bit, the gist contouring algorithm looks to my eye like Paul Bourke's CONREC algorithm, which may or may not be patented.