BOUBA
Guest
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 Posted:
Sun Nov 20, 2005 5:10 pm Post subject:
VBA assistance |
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Dear Friends,
I am a new subscriber, and I would like to ask for your assistance
regarding a simple VBA program:
I would like to know how to write the VBA algorithm for the following
program :
Computing Clockwise Rotation
Determining if a point is to the left or right of a line
One effective computational geometry task is to determine if a point is
located clockwise from
a straight line. This is useful to determine if a point is inside a
polygon, or if a house is located
on a particular side of the street.
Given a straight line segment, and an individual point as defined
below:
Line := (10,10)
(50,50)
Point := (25,26)
The cross product of the line matrix can be computed through standard
arithmetic. If the
sign of the cross product is positive, then the directed segment p1pn
is clockwise from p1p2.
Crossprod:=(point0-line0,0).[line1,1-line0,1]-(line1,0-line0,0).(point1-line0,1)
Crossprod=-40
I am looking forward your assistance at your soonest convenience
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