Matplotlib底图:消除海洋 [英] Matplotlib Basemap: Removing Ocean
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问题描述
我有一个网格图,要在底图上覆盖大洲.我正在使用此代码:
I have an meshplot onto which I want to overlay continents in basemap. I am using this code:
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
m = Basemap(width=12000000,height=9000000,projection='lcc',
resolution=None,lat_1=45.,lat_2=55,lat_0=50,lon_0=-107.)
m.drawlsmask(land_color='coral',ocean_color='aqua',lakes=True)
plt.show()
引用此,我的要求是对面的.我希望在网格图或图像的顶部都具有大洲,因此只能看到海洋区域的网格.
referring to this, my requirements is opposite. I want continents ontop of the meshplot or image I have so only mesh at the ocean area is visible.
推荐答案
您的要求:
- 在网格图和/或图像上方具有大洲的图
- 仅可见海洋区域的网格/图像
要获取图表,必须在涉及的每个图层中使用"zorder".要绘制的数据必须适当地转换.这是您可以尝试使用的代码,以及它产生的输出图.
To get the plot, you must use 'zorder' in each of the layers involved. The data to plot must be transformed appropriately. Here is a code that you can try, and the output plot it produces.
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
import numpy as np
m = Basemap(projection='lcc', width=12000000, height=9000000,
resolution='c', lat_1=45., lat_2=55, lat_0=50, lon_0=-107.)
# if resolution is None, coastlines wont draw
# draw only land areas with zorder=20
# any other layers with zorder below 20 will be hidden by land areas
m.drawlsmask(land_color='coral', ocean_color='none', lakes=True, zorder=20)
m.drawcoastlines(linewidth=0.3, color='gray', zorder=25)
filename = "small_01.png" #use your image here
lonmin, lonmax, latmin, latmax = (-130, -40, 35, 45) # set limits of the image
# compute the limits of the image in data coordinates
left, bottom = m (lonmin, latmin)
top, right = m(lonmax, latmax)
image_extent = (left, right, bottom, top)
ax = plt.gca()
# set zorder < 20, to plot the image below land areas
ax.imshow(plt.imread(filename), extent=image_extent, zorder=15)
# plot some meshgrid data
# set zorder above image, but below land
xs = np.linspace(-130, -60, 20)
ys = np.linspace(20, 60, 10)
x2d, y2d = np.meshgrid(xs, ys)
#ax.plot(*m(x2d, y2d), 'ro', zorder=16) # faster
ax.scatter(*m(x2d, y2d), s=2, zorder=16)
plt.show()
编辑1
一些有用的代码段:
# This plots shaded relief terrain covering land and sea.
m.shadedrelief(zorder = 25)
# This plots only ocean/sea parts on top.
m.drawlsmask(land_color='none', ocean_color='aqua', zorder=26)
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