Question

当其他条件如+180和-180时，它将变为rigtht。当0应该在右边时，它没有出现。

该网站的结果是相同的，没有正确的0

https://scitools.org.uk/cartopy/docs/latest/gallery/tick_labels.html?highlight=tick

我已经阅读了地轴代码，并尝试另一种方法来显示rigtht中的0。

如果使用matplotlib方法，结果将更加错误。

如果使用Cartopy地图网格线和刻度线标签，则结果相同。

https://scitools.org.uk/cartopy/docs/latest/matplotlib/gridliner.html#cartopy.mpl.gridliner.Gridliner.xformatter

#===================================================
#plot the world map central 180 
#===================================================
import matplotlib.pyplot as plt
import cartopy.crs as ccrs
import cartopy.feature as cfeature
from cartopy.mpl.ticker import LongitudeFormatter, LatitudeFormatter
def make_map(scale):
    fig=plt.figure(figsize=(8, 10))
    ax=plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
    ax.set_global()
    land = cfeature.NaturalEarthFeature('physical', 'land', scale,edgecolor='face',
                                                              facecolor=cfeature.COLORS['land'])
    ax.add_feature(land, facecolor='0.75')
    ax.coastlines(scale)
    #===set tick
    ax.set_xticks([0, 60, 120, 180, 240, 300, 360], crs=ccrs.PlateCarree())
    ax.set_yticks([-90, -60, -30, 0, 30, 60, 90], crs=ccrs.PlateCarree())

    lon_formatter = LongitudeFormatter(zero_direction_label=False)
    lat_formatter = LatitudeFormatter()
    ax.xaxis.set_major_formatter(lon_formatter)
    ax.yaxis.set_major_formatter(lat_formatter)
    #=====set grid
    #gl = ax.gridlines()
    ax.grid()
    return fig,ax
fig,ax=make_map(scale='110m')

enter image description here

Answer 1

在我看来，应该显示在右侧的零也显示在左侧；请注意该ticklabel如何比其他的大胆？

原因似乎是360％360 == 0，所以滴答声一直旋转到起点。

一种解决方法是将最后一个刻度设置为略微偏移，例如

[0, 60, 120, 180, 240, 300, 359.9999999999]

或

[0, 60, 120, 180, -120, -60, -1e-10]

示例：

import matplotlib.pyplot as plt
import cartopy.crs as ccrs
import cartopy.feature as cfeature
from cartopy.mpl.ticker import LongitudeFormatter, LatitudeFormatter
def make_map(scale):
    fig=plt.figure(figsize=(8, 6))
    ax=plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
    ax.set_global()
    land = cfeature.NaturalEarthFeature('physical', 'land', scale,edgecolor='face',
                                        facecolor=cfeature.COLORS['land'])
    ax.add_feature(land, facecolor='0.75')
    ax.coastlines(scale)

    ax.set_xticks([0, 60, 120, 180, 240, 300, 359.9999999999], crs=ccrs.PlateCarree())
    ax.set_yticks([-90, -60, -30, 0, 30, 60, 90], crs=ccrs.PlateCarree())

    lon_formatter = LongitudeFormatter(zero_direction_label=True)
    lat_formatter = LatitudeFormatter()
    ax.xaxis.set_major_formatter(lon_formatter)
    ax.yaxis.set_major_formatter(lat_formatter)

    ax.grid()
    return fig,ax

fig,ax=make_map(scale='110m')
plt.show()

当central_longitude = 180时无法在右边显示0滴答声

1 个答案: