plot.py 文件源码

def plot_map(ax=None, alpha=0.3, zorder=0):
    """
    Add map features (coastlines, national boundaries, etc.) to *a*
    with transparency level *alpha* and *zorder*. Return *ax*.
    """
    if ax is None:
        ax = PL.axes(projection=ccrs.PlateCarree())
    # national boundaries
    boundaries_50m = cartopy.feature.NaturalEarthFeature(category='cultural',
                                                         name='admin_0_boundary_lines_land',
                                                         scale='50m',
                                                         edgecolor='k',
                                                         facecolor='none')
    ax.add_feature(boundaries_50m,
                   alpha=alpha,
                   zorder=zorder)
    # states
    states_50m = cartopy.feature.NaturalEarthFeature(category='cultural',
                                                     name='admin_1_states_provinces_lines',
                                                     scale='50m',
                                                     edgecolor='k',
                                                     facecolor='none')
    ax.add_feature(states_50m,
                   alpha=alpha,
                   zorder=zorder)
    # coastlines
    coastline_50m = cartopy.feature.NaturalEarthFeature('physical',
                                                        'coastline',
                                                        '50m',
                                                        edgecolor='k',
                                                        facecolor='none')
    ax.add_feature(coastline_50m,
                   alpha=alpha,
                   zorder=zorder)
    # lakes
    lakes_110m = cartopy.feature.NaturalEarthFeature('physical',
                                                     'lakes',
                                                     '110m',
                                                     edgecolor='k',
                                                     facecolor='none')
    # add all shape objects
    ax.add_feature(lakes_110m,
                   alpha=alpha,
                   zorder=zorder)

    return ax