MapWinGeoProc:Utils IsLeft
From MapWindow GIS
IsLeft
Syntax
double IsLeft(System.Double x0, System.Double y0, System.Double x1, System.Double y1, System.Double x2, System.Double y2)
Summary
Tests if a point is left|on|right of an infinite line.
See: the January 2001 Algorithm "Area of 2D and 3D Triangles and Polygons"
at http://softsurfer.com/Archive/algorithm_0101/algorithm_0101.htm
Parameters
| x0 | X value for point 0 of the line. |
| y0 | Y value for point 0 of the line. |
| x1 | X value for point 1 of the line. |
| y1 | Y value for point 1 of the line. |
| x2 | X value of the point being tested. |
| y2 | Y value of the point being tested. |
Returns
A value > 0 if the point is left of the line.
A value = 0 if the point is on the line.
A value less than 0 if the point right of the line.
Visual Basic Net 2005 Example Implementation Code
Visual C# 2005 Example Implementation Code
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