
Re: Classification of quadrilaterals
Posted:
Dec 21, 1994 6:48 AM


There appear to be a number of 'computational geometry' algorithms that involve splitting larger polygons up into (convex) trapezoids and working out various facts for these simple objects. The process often begins with sweeping a line of fixed slope through the object, picking up vertices and drawing those lines in  creating a set of trapezoids (or triangles which are thought of as degenerate trapezoids). Last year at the Cinicnnati meeting Joe Malkovitch mentioned a recent IBM patent on dividing polygons into trapezoids.
Of course all that fits John's observation  just simple convenience because people would rather not really 'do geometry'!
Walter Whiteley

