把{"metaInfo":{"apiDescription":"hmiserver api","currentTime":"20200409T213249428Z"},"payloadItem":{"routePath":[[{"jobModel":0,"kappa":0.0,"relativeTime":0.0,"s":0.0,"theta":-0.033711594924239571,"v":4.1699999999999999,"x":268023.5661949619,"y":3939971.0870088288},{"jobModel":0,"kappa":0.0,"relativeTime":0.10000000000000001,"s":0.41700000000000004,"theta":-0.033711594924239571,"v":4.1699999999999999,"x":268023.98295803001,"y":3939971.0729537564}],[{"jobModel":0,"kappa":0.0,"relativeTime":0.0,"s":0.0,"theta":-0.033711594924239571,"v":4.1699999999999999,"x":268023.5661949619,"y":3939971.0870088288},{"jobModel":0,"kappa":0.0,"relativeTime":0.10000000000000001,"s":0.41700000000000004,"theta":-0.033711594924239571,"v":4.1699999999999999,"x":268023.98295803001,"y":3939971.0729537564}]]}}这种格式文件中的x,y坐标提取出来用pyplot画成路径图，并且把[268002.1082035586,3939994.353474072],[268252.94345078256,3939985.894218068],[268248.1305912363,3939843.182516996],[267997.2953440123,3939851.641773]这四个点画成四边形外边界的代码怎么写

要绘制四边形外边界，你可以在绘制路径图之前添加额外的代码来绘制这个四边形。下面是修改后的代码示例：

import json
import matplotlib.pyplot as plt
from matplotlib.patches import Polygon

# 读取文件
with open('your_file.json', 'r') as f:
    data = json.load(f)

# 提取x和y坐标
x_coords = []
y_coords = []

route_path = data['payloadItem']['routePath']
for path in route_path:
    for point in path:
        x_coords.append(point['x'])
        y_coords.append(point['y'])

# 绘制路径图
plt.plot(x_coords, y_coords)

# 绘制四边形外边界
polygon_coords = [[268002.1082035586, 3939994.353474072],
                  [268252.94345078256, 3939985.894218068],
                  [268248.1305912363, 3939843.182516996],
                  [267997.2953440123, 3939851.641773]]
polygon = Polygon(polygon_coords, closed=True, fill=None, edgecolor='red')
plt.gca().add_patch(polygon)

plt.xlabel('X')
plt.ylabel('Y')
plt.title('Path with Polygon')
plt.show()

在这个示例代码中，我们使用`matplotlib.patches.Polygon`类来绘制四边形外边界，然后将它添加到路径图中。四边形的坐标被存储在`polygon_coords`变量中。运行此代码将生成一个带有路径和四边形外边界的图形。请将`your_file.json`替换为包含路径数据的文件的路径。