要在 Basemap 中针对特定情况解决此问题,您可以检查结果路径中 x 顶点的差异。从那里,我们可以将坏路分成两部分。我已经将自己的示例与底图放在一起:
from mpl_toolkits.basemap import Basemap
import numpy as np
import matplotlib.pyplot as plt
m = Basemap(projection='cyl', lon_0=0, resolution='c')
m.fillcontinents(color='coral',lake_color='aqua')
m.drawmapboundary(fill_color='aqua')
places = {'Mexico City': (19.05, -99.366667),
'London': (51.507222, -0.1275),
'Sydney': (-33.859972, 151.211111),
'Cape Town': (-33.925278, 18.423889),
'Delhi': (28.61, 77.23),
}
network = [
('London', 'Delhi'),
('Mexico City', 'Sydney'),
]
for source, target in network:
lat1, lon1 = places[source]
lat2, lon2 = places[target]
line, = m.drawgreatcircle(lon1, lat1, lon2, lat2, lw=3)
p = line.get_path()
# find the index which crosses the dateline (the delta is large)
cut_point = np.where(np.abs(np.diff(p.vertices[:, 0])) > 200)[0]
if cut_point:
cut_point = cut_point[0]
# create new vertices with a nan inbetween and set those as the path's vertices
new_verts = np.concatenate(
[p.vertices[:cut_point, :],
[[np.nan, np.nan]],
p.vertices[cut_point+1:, :]]
)
p.codes = None
p.vertices = new_verts
plt.show()
结果:
这不是一个通用的解决方案,只有当你有纬度和经度时才有效。解决一般问题要困难得多,并且是cartopy 的重点 (http://scitools.org.uk/cartopy/docs/latest/)。在接下来的几天里,我将在 cartopy 中发布一个完全相同的情节的例子。
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