导入的shapefile外部的掩码区域(底图/ matplotlib)

Question

我正在通过Matplotlib在美国和加拿大东海岸的底图上绘制数据.除了基础层(填充的等高线图),我使用Matplotlib的readshapefile工具在数据顶部覆盖了这个焦点区域的shapefile.

我想知道如何掩盖shapefile之外的所有网格数据.我显然可以通过Matplotlib做一个maskocean命令,但我仍然留在圣劳伦斯以西的填充轮廓.现在有人怎么做？我在线搜索没有太多运气.

def make_map(lon,lat,param):
    fig, ax = plt.subplots()
    ax.axis('off')
    x1 = -83.
    x2 = -57.
    y1 = 37.
    y2 = 50.
    projection='merc'
    resolution='h'
    m = Basemap(projection=projection, llcrnrlat=y1, urcrnrlat=y2, llcrnrlon=x1,
                urcrnrlon=x2, resolution=resolution)
    x,y = m((lon-360.),lat)
    m.ax = ax
    my_cmap = cm.get_cmap('coolwarm')
    pp = m.contourf(x, y, param, 30, cmap=my_cmap, extend='both')  
    m.drawmapscale(-67, 39.5, -70, 43.5, 500, fontsize=8, barstyle='fancy') 
    return fig, m, x, y

def drawstates(ax, shapefile='../StateProv_UTMrp'):
        shp = m.readshapefile(shapefile, 'states',zorder = 1, drawbounds=True)
        for nshape, seg in enumerate(m.states):
            poly = Polygon(seg, facecolor='w',alpha=0.0, edgecolor='k')
            ax.add_patch(poly)

fig, m, x, y = make_map(lon, lat, param)
drawstates(m.ax)

Answer 1

我想我刚刚找到的这篇文章可以给你一些帮助。但我不确定这是否是完整的答案。

http://basemaptutorial.readthedocs.org/en/latest/clip.html