Divide a single polygon (with several outer-contour components) into
several polygons, a polygon for each outer contour, by modifying the
PID and SID indices.
dividePolys (polys)PolySet, possibly with the addition of an SID column if
it did not already exist. The function may also reorder columns such
that PID, SID, POS, X and Y appear
first, in that order.
PolySet with one or more polygons, each with possibly several components/holes.
Nicholas M. Boers, Staff Software Engineer
Jobber, Edmonton AB
Last modified Rd: 2007-06-06
Given the input PolySet, this function renumbers the PID
and SID indices so that each outer contour has a unique PID and
is followed by all of its holes, identifying them with SIDs
greater than one.
combinePolys.