Question

使用this solution作为基础，是否可以创建从同一来源发出的不同目标的多个箭头？例如德里 - ＆gt;北京（116.4,39.9），德里 - ＆gt;开罗（30.0,31.2），德里 - ＆gt;东京（35.6,139.6）？

当我重复下面的代码时，我只得到第一个箭头。

#Dehli - Beijing  
    ax.annotate('Beijing', xy=(116.4, 39.9), xycoords=transform,
            size=40,
            )

    ax.annotate('Delhi', xy=(113, 40.5), xytext=(77.23, 28.61),
            size=40,
            arrowprops=dict(facecolor='red', ec = 'none',
                            arrowstyle="fancy",
                            connectionstyle="arc3,rad=-0.2",
                           ),
            xycoords=transform,
               )

#Dehli - Cairo  
    ax.annotate('Cairo', xy=(-6.26, 53.34), xycoords=transform,
            size=40,
            )

    ax.annotate('Delhi', xy=(113, 40.5), xytext=(77.23, 28.61),
            size=40,
            arrowprops=dict(facecolor='red', ec = 'none',
                            arrowstyle="fancy",
                            connectionstyle="arc3,rad=-0.2",
                           ),
            xycoords=transform,
               )

或者，是否有办法将.annotate放入此表达式中，我目前正在使用它来绘制连接线。我试着无济于事：

#Coordinates
lon_dehl, lat_dehl = 116.4, 39.9
lon_beij, lat_beij = 77.59, 12.97
lon_toky, lat_toky = 35.6, 139.6
lon_cair, lat_cair = 30.0, 31.2

plt.plot([lon_dehl, lon_beij], [lat_dehl, lat_beij],
     linewidth=2,
         linestyle='solid',
         solid_capstyle='round',
         color='#cb2c31',
        marker='o', 
         markersize=6,
         markeredgewidth=None, 
         markeredgecolor='#cb2c31',
     transform=ccrs.PlateCarree(),
        )

Answer 1

This isn't perfect (in fact, I'd welcome any improvements), but I achieved multiple arrows with annotate.

The theory is: use the same source for all arrows, but alter the target lat-lons (or more correctly, lon-lat). Seems obvious now.

Also, don't use annotate for city names. Annotate seems to put the name at the start of the arrow rather than the endpoint.

As I say, I'd welcome any suggestions for improvements (incl. for labelling).

import matplotlib.pyplot as plt
import cartopy.crs as ccrs
import cartopy.feature as cfeature
from pyproj import Proj, transform

def main():
    ax = plt.axes(projection=ccrs.PlateCarree())
    ax.set_extent([-150, 60, -25, 60])

    ax.add_feature(cfeature.LAND)
    ax.add_feature(cfeature.OCEAN)
    ax.add_feature(cfeature.COASTLINE)
    ax.add_feature(cfeature.BORDERS)


    #Labels - city locations & names
    ax.plot(77.20, 28.61, 'bo', markersize=7, transform=ccrs.Geodetic())
    ax.text(65, 33, 'Dehli', transform=ccrs.Geodetic())

    ax.plot(139.69, 35.68, 'bo', markersize=7, transform=ccrs.Geodetic())
    ax.text(139.69, 35.68, 'Tokyo', transform=ccrs.Geodetic())

    ax.plot(0.12, 51.50, 'bo', markersize=7, transform=ccrs.Geodetic())
    ax.text(0.12, 51.50, 'London', transform=ccrs.Geodetic())

    ax.plot(-71.05, 42.36, 'bo', markersize=7, transform=ccrs.Geodetic())
    ax.text(-71.05, 42.36, 'New York', transform=ccrs.Geodetic())

    ax.plot(151.81, -33.86, 'bo', markersize=7, transform=ccrs.Geodetic())
    ax.text(151.81, -33.86, 'Sydney', transform=ccrs.Geodetic())

    ax.plot(-43.2, -22.9, 'bo', markersize=7, transform=ccrs.Geodetic())
    ax.text(-43.2, -22.9, 'Rio', transform=ccrs.Geodetic())


    #Arrows lines 

    transform = ccrs.PlateCarree()._as_mpl_transform(ax)


    #Dehli to Tokyo
    ax.annotate('', xy=(139.69, 35.68), xytext=(77.20, 28.61),
            xycoords='data',
            size=20,
            arrowprops=dict(facecolor='red', ec = 'none',
                            arrowstyle="fancy",
                            connectionstyle="arc3,rad=-0.3"))

    #Dehli to London
    ax.annotate('', xy=(0.12, 51.50), xytext=(77.20, 28.61), 
            size=10,
            xycoords='data',
            arrowprops=dict(facecolor='red', ec = 'none',
                            arrowstyle="fancy",
                            connectionstyle="arc3,rad=-0.3"))

    #Dehli to New York
    ax.annotate('', xy=(-71.05, 42.36), xytext=(77.20, 28.61),
            xycoords='data',
            size=30,
            arrowprops=dict(facecolor='red', ec = 'none',
                            arrowstyle="fancy",
                            connectionstyle="arc3,rad=-0.3"))

    #Dehli to Sydney
    ax.annotate('', xy=(151.81, -33.86), xytext=(77.20, 28.61),
            xycoords='data',
            size=10,
            arrowprops=dict(facecolor='red', ec = 'none',
                            arrowstyle="fancy",
                            connectionstyle="arc3,rad=-0.3"))

    #Dehli to Rio
    ax.annotate('', xy=(-43.2, -22.9), xytext=(77.20, 28.61),
            xycoords='data',
            size=20,
            arrowprops=dict(facecolor='red', ec = 'none',
                            arrowstyle="fancy",
                            connectionstyle="arc3,rad=-0.3")
               )


    #plt.tight_layout()
    plt.show()


if __name__ == '__main__':
    main()

Cartopy - 使用注释的多个箭头

1 个答案: