adapter.py 文件源码

def _isClockwise(self, coords):
        # A modified shoelace algorithm to determine polygon orientation.
        # See https://en.wikipedia.org/wiki/Shoelace_formula
        n = len(coords)
        area = 0.0
        for i in range(n):
            j = (i + 1) % n
            area += coords[i][0] * coords[j][1]
            area -= coords[j][0] * coords[i][1]
        return area < 0.0