使用matplotlib绘制shapefile

我正在尝试读取shapefile并使用matplotlib对其进行绘制。这是代码：

import matplotlib.pyplot as plt
import shapefile   

shpFilePath = "D:\test.shp"  
listx=[]
listy=[]
test = shapefile.Reader(shpFilePath)
for sr in test.shapeRecords():
    for xNew,yNew in sr.shape.points:
        listx.append(xNew)
        listy.append(yNew)
plt.plot(listx,listy)
plt.show()

但是，我得到了连接多边形的线。如何绘制多边形，使它们成为shapefile中的方式。这是使用ArcGIS打开时的图和shapefile的屏幕截图。

我将留给您如何收集形状，但这是原理

import numpy as np
from matplotlib import pyplot as p  #contains both numpy and pyplot
x1 = [-1,-1,10,10,-1]; y1 = [-1,10,10,-1,-1]
x2 = [21,21,29,29,21]; y2 = [21,29,29,21,21]
shapes = [[x1,y1],[x2,y2]]
for shape in shapes:
  x,y = shape
  p.plot(x,y)
p.show()

为了将来参考，以下是我按照上面的建议提出的解决方案。

import shapefile as shp  # Requires the pyshp package
import matplotlib.pyplot as plt

sf = shp.Reader("test.shp")

plt.figure()
for shape in sf.shapeRecords():
    x = [i[0] for i in shape.shape.points[:]]
    y = [i[1] for i in shape.shape.points[:]]
    plt.plot(x,y)
plt.show()

生成的图形将非常丰富多彩，但是随后，您只需要调整plot关键字即可。

您需要使用matplotlib 路径和补丁，并且有一个Python模块专用于使用这些函数Descartes从shapefile中绘制多边形。

由于Pyshp（shapefile）具有geo_interface（PyShp的新geo_interface）约定，因此可以使用它。

polys  = shapefile.Reader("polygon")
# first polygon
poly = polys.iterShapes().next().__geo_interface__
print poly
{'type': 'Polygon', 'coordinates': (((151116.87238259654, 135890.8706318218), (153492.19971554304, 134793.3055883224), (153934.50204650551, 133892.31935858406), (152623.97662143156, 131811.86024627919), (150903.91200102202, 130894.49244872745), (149347.66305874675, 132991.33312884573), (149151.08424498566, 134383.76639298678), (151116.87238259654, 135890.8706318218)),)}

结果是几何的GeoJSON表示形式，您可以使用如何使用matplotlib / python绘制地理数据的解决方案

import matplotlib.pyplot as plt 
from descartes import PolygonPatch
BLUE = '#6699cc'
fig = plt.figure() 
ax = fig.gca() 
ax.add_patch(PolygonPatch(poly, fc=BLUE, ec=BLUE, alpha=0.5, zorder=2 ))
ax.axis('scaled')
plt.show()

可以使用此答案中讨论的geopandas或pyshp来完成。Geopandas在其后端使用matplotlib进行绘图。

除了ldocao回答之外，并回答FaCoffee问题。如果您有孤立的孤岛并且它们是同一功能的一部分，则可以尝试以下操作：

import shapefile as shp
import matplotlib.pyplot as plt

sf = shp.Reader("test.shp")

plt.figure()
for shape in sf.shapeRecords():
    for i in range(len(shape.shape.parts)):
        i_start = shape.shape.parts[i]
        if i==len(shape.shape.parts)-1:
            i_end = len(shape.shape.points)
        else:
            i_end = shape.shape.parts[i+1]
        x = [i[0] for i in shape.shape.points[i_start:i_end]]
        y = [i[1] for i in shape.shape.points[i_start:i_end]]
        plt.plot(x,y)
plt.show()

这使它为我工作。形状的属性“部分”返回要素内部不同几何形状的起始索引。

但是，在一个shapefile形状中，可能会有多个部分。这将分别在一个形状中绘制每个零件。

import matplotlib.pyplot as plt
import shapefile
import numpy as np

this_shapefile = shapefile.Reader(map_file_base) # whichever file
shape = this_shapefile.shape(i) # whichever shape
points = np.array(shape.points)

intervals = list(shape.parts) + [len(shape.points)]

ax = plt.gca()
ax.set_aspect(1)

for (i, j) in zip(intervals[:-1], intervals[1:]):
    ax.plot(*zip(*points[i:j]))