Hi Matthew,

I've been working on "rolling/windowed" libraries for quite a while. 

I'm currently working on implementations for basic moment and rank statistics - they are pretty much done and I am trying to maneuver them into  apache commons math for java.

I am also interested in implementing these statistics for python/numpy and R.  I have seen a little bit for R, but nothing yet for numpy.

/brad

On Nov 25, 2007 5:00 PM, Matthew Perry < perrygeo@gmail.com> wrote:
Hi all,

 I'm not sure if my terminology is familiar but I'm trying to do a
"moving window" analysis (ie a spatial filter or kernel) on a 2-D
array representing elevation. For example, a 3x3 window centered on
each cell is used to calculate the derivate slope of that cell.

 Can this easily be implemented using numpy?

 Currently I have tried implementing in pure python loops (too slow)
and c++ (fast but more difficult to compile, distribute, wrap in
python calls, etc). I think a good solution would be to leverage numpy
which is both fast and and easy package for end users to install.

 An example of the C++ code I'm trying to emulate is at
http://perrygeo.net/download/hillshade.html . Does anyone have any
tips or examples out there? Where should I start researching this?

--
Matthew T. Perry
http://www.perrygeo.net
_______________________________________________
Numpy-discussion mailing list
Numpy-discussion@scipy.org
http://projects.scipy.org/mailman/listinfo/numpy-discussion