<p>这是我用来绘制多边形形状文件的另一段代码。它使用GDAL/OGR读取shapefile并正确绘制甜甜圈形状多边形:</p>
<pre><code>from osgeo import ogr
import numpy as np
import matplotlib.path as mpath
import matplotlib.patches as mpatches
import matplotlib.pyplot as plt
# Extract first layer of features from shapefile using OGR
ds = ogr.Open('world_countries_boundary_file_world_2002.shp')
nlay = ds.GetLayerCount()
lyr = ds.GetLayer(0)
# Get extent and calculate buffer size
ext = lyr.GetExtent()
xoff = (ext[1]-ext[0])/50
yoff = (ext[3]-ext[2])/50
# Prepare figure
fig = plt.figure()
ax = fig.add_subplot(111)
ax.set_xlim(ext[0]-xoff,ext[1]+xoff)
ax.set_ylim(ext[2]-yoff,ext[3]+yoff)
paths = []
lyr.ResetReading()
# Read all features in layer and store as paths
for feat in lyr:
geom = feat.geometry()
codes = []
all_x = []
all_y = []
for i in range(geom.GetGeometryCount()):
# Read ring geometry and create path
r = geom.GetGeometryRef(i)
x = [r.GetX(j) for j in range(r.GetPointCount())]
y = [r.GetY(j) for j in range(r.GetPointCount())]
# skip boundary between individual rings
codes += [mpath.Path.MOVETO] + \
(len(x)-1)*[mpath.Path.LINETO]
all_x += x
all_y += y
path = mpath.Path(np.column_stack((all_x,all_y)), codes)
paths.append(path)
# Add paths as patches to axes
for path in paths:
patch = mpatches.PathPatch(path, \
facecolor='blue', edgecolor='black')
ax.add_patch(patch)
ax.set_aspect(1.0)
plt.show()
</code></pre>