https://www.cnblogs.com/zzcpy/p/10524348.html
维基百科-鞋带公式:https://en.wikipedia.org/wiki/Shoelace_formula
def polygon_area(points): """返回多边形面积 """ area = 0 q = points[-1] for p in points: area += p[0] * q[1] - p[1] * q[0] q = p return area / 2
最后记得绝对值一下