[R-sig-Geo] Seeking example of making polygons from non-uniform grid

[Waichler, Scott R]

Hi,

I have a rectangular grid with varying cell sizes in the x and y
directions.  I am looking for an example on how to efficiently create sp
polygon objects given a complete description of the grid.  For each
cell, I have coordinates for the vertices and a value (z), which is my
case is a categorical variable.  Previously Roger Bivand suggested how I
could merge contiguous, like-valued cells into a single polygon, but the
example assumed a regular grid with uniform dx and dy.

Thanks for your help,
Scott

Scott Waichler, Senior Research Scientist
Pacific Northwest National Laboratory
MSIN K9-36
P.O. Box 999
Richland, WA   99352    USA
509-372-4423 (voice)
509-372-6089 (fax)
scott.waichler at pnl.gov
http://hydrology.pnl.gov