Rectangular selections from 2D piddles are easy and fast with the
range operator. However, I would like to grab a non-rectangular
selection out of a piddle, setting all out-of-area-of-interest
elements to BAD.

Background --

- The user clicks on a map and creates an irregular polygon
- I (somehow **) figure out the piddle elements, aka cells, that lie
within the drawn poly
- Out of the base piddle, I grab the tightest rect that contains the
cells within the drawn poly (the min. bounding box)
- Set all the cells outside the drawn poly to BAD so they don't figure
in the rest of the calculations

I searched the docs, but the closest discussion I found was on
convex-hulls from June 2005 [1]. Suggestions?

** the reason I say "somehow" is because I can do a lookup using a
database to get the indices of the mouse-clicks, and the elements that
lie within the bounding rect, but I would prefer to do this without a
database. I am generally finding PDL to be substantively faster than a
database, and would like to stay out of a db as much as possible. I
initiated a discussion on this a while back, but that was restricted
to rectangular selects.

[1] http://mailman.jach.hawaii.edu/pipermail/perldl/2005-June/000036.html

-- 
Puneet Kishor http://www.punkish.org
Carbon Model http://carbonmodel.org
Charter Member, Open Source Geospatial Foundation http://www.osgeo.org
Science Commons Fellow, http://sciencecommons.org/about/whoweare/kishor
Nelson Institute, UW-Madison http://www.nelson.wisc.edu
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