Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Re: how to find the points inside a curvature shape
Posted:
Jan 23, 2013 1:12 PM


"Tinith " <snoopcat@live.com> wrote in message <kdp38c$d9g$1@newscl01ah.mathworks.com>... > Hi, i have a polygon (e.g: rectangle) where it has equally spaced points (coordinates are known) inside it. then i need to draw a curvature shape (e.g: clothoid cuve, ellipse) inside this polygon. what i want to achieve is to find the coordinates of the points which is covered by the curvature shape.           If by "shape" you mean the region enclosed by a closed curve, then use the inequality available from the equation of that curve. For an ellipse with equation
A*x^2+B*x*y+C*y^2+D*x+E*y+F = 0
you would test your points with the inequality
sign(A)*(A*x^2+B*x*y+C*y^2+D*x+E*y+F) <= 0
With a clothoid curve (cornu or Euler spiral), which is not a closed curve, I have no idea what it would be that you want. It has no inside or outside, only points along an infinitely thin curve. What would you call its "shape"?
Roger Stafford



