Convert polygon contour to counterclockwise vertex ordering
[x2,y2] = poly2ccw(x1,y1)
[x2,y2] = poly2ccw(x1,y1) arranges the Cartesian
vertices in the polygonal contour (x1,y1) in
counterclockwise order, returning the result in x2 and
y2. If x1 and
y1 can contain multiple contours, represented
either as NaN-separated vectors or as cell arrays,
then each contour is converted to clockwise ordering.
x2 and y2 have the same
format (NaN-separated vectors or cell arrays) as
x1 and y1.
Convert a clockwise-ordered square to counterclockwise ordering.
x1 = [0 0 1 1 0];
y1 = [0 1 1 0 0];
ispolycw(x1, y1)
ans =
1
[x2, y2] = poly2ccw(x1, y1);
ispolycw(x2, y2)
ans =
0You can use poly2ccw for geographic coordinates if the
polygon does not cross the Antimeridian or contain a pole. A polygon
contains a pole if the longitude data spans 360 degrees. To use
poly2ccw with geographic coordinates,
specify the longitude vector as x1 and the latitude
vector as y1.