Convert polygon contour to clockwise vertex ordering
[x2, y2] = poly2cw(x1, y1)
[x2, y2] = poly2cw(x1, y1) arranges the Cartesian
vertices in the polygonal contour (x1,
y1) in clockwise 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 counterclockwise-ordered square to clockwise ordering.
x1 = [0 1 1 0 0];
y1 = [0 0 1 1 0];
ispolycw(x1, y1)
ans =
0
[x2, y2] = poly2cw(x1, y1);
ispolycw(x2, y2)
ans =
1
You can use poly2cw 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
poly2cw with geographic coordinates,
specify the longitude vector as x1 and the latitude
vector as y1.