有没有办法移动地图以显示整个大圆路线？ （底图）

Question

我试图为我的文书工作制作一个程序，该程序将实时显示两个城市之间的范围，我想要但我遇到了一个我无法处理的问题。

实际地图是这样的：

代码：

from mpl_toolkits.basemap import Basemap
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.widgets import Slider

# Create new figure, axes instances.
fig = plt.figure()
ax = fig.add_axes([0.1, 0.3, 0.8, 0.6])  # Adjusted axes position for the map.

# Setup mercator map projection.
m = Basemap(llcrnrlon=-180., llcrnrlat=-60., urcrnrlon=180., urcrnrlat=85.,
            rsphere=(6378137.00, 6356752.3142),
            resolution='l', projection='merc',
            lat_0=40., lon_0=-20., lat_ts=20.)

# Define latitude and longitude coordinates for Singapore (sglat, sglon) and San Francisco (sflat, sflon).
sglat = 1.35
sglon = 103.82
sflat = 37.77
sflon = -122.42

# Calculate points along the great circle route.
num_points = 1000
lons, lats = m.gcpoints(sglon, sglat, sflon, sflat, num_points)

# Draw great circle route between Singapore and San Francisco.
m.drawgreatcircle(sglon, sglat, sflon, sflat, linewidth=2, color='b')
m.drawcoastlines()
m.fillcontinents()

# Draw parallels and meridians.
m.drawparallels(np.arange(-90, 90, 20), labels=[1, 1, 0, 1])
m.drawmeridians(np.arange(-180, 180, 30), labels=[1, 1, 0, 1])

ax.set_title('Great Circle from Singapore to San Francisco')

# Create a slider for animation.
slider_ax = fig.add_axes([0.25, 0.1, 0.5, 0.03])
slider = Slider(slider_ax, 'Position', 0, 1, valinit=0)

# Initialize the marker.
marker, = ax.plot([], [], marker='o', markersize=8, color='r')


# Function to update marker position based on slider value.
def update_marker(val):
    position = int(val * (num_points - 1))  # Calculate the index along the route.
    lon, lat = lons[position], lats[position]
    marker.set_data([lon], [lat])  # Pass lon and lat as sequences
    fig.canvas.draw_idle()


# Connect the slider to the update function.
slider.on_changed(update_marker)

plt.show()

所以一般我希望整个路线显示在中间。非常感谢您的帮助。

Answer 1

解决方案：

将 lon_0“地图中心经度”偏移为您的旅行路径中心左侧 180 度（直线距离）。