立体投影有两点,如图所示:
这些点应该位于圆的一角形的终点上。如何绘制一个通过这两点的圆圈?
上述情节的代码:
import matplotlib.pylab as plt
from mpl_toolkits.basemap import Basemap
import numpy as np
from scipy.interpolate import splev, splrep
# create instance of basemap, note we want a south polar projection to 90 = E
myMap = Basemap(projection='spstere',boundinglat=0,lon_0=180,resolution='l',round=True,suppress_ticks=True)
# set the grid up
gridX, gridY = 10.0, 15.0
parallelGrid = np.arange(-90.0,90.0,gridX)
meridianGrid = np.arange(-180.0,180.0,gridY)
# draw parallel and meridian grid, not labels are off. We have to manually create these.
myMap.drawparallels(parallelGrid,labels=[False,False,False,False])
myMap.drawmeridians(meridianGrid,labels=[False,False,False,False],labelstyle='+/-',fmt='%i')
# plot azimuth labels, with a North label.
ax = plt.gca()
ax.text(0.5,1.025,'N',transform=ax.transAxes,horizontalalignment='center',verticalalignment='bottom',size=25)
for para in np.arange(gridY,360,gridY):
x= (1.1*0.5*np.sin(np.deg2rad(para)))+0.5
y= (1.1*0.5*np.cos(np.deg2rad(para)))+0.5
ax.text(x,y,u'%i\N{DEGREE SIGN}'%para,transform=ax.transAxes,horizontalalignment='center',verticalalignment='center')
summerAzi = np.array([0, 360])
summerAlt = np.array([40, 4])
summerX, summerY = myMap(summerAzi, -summerAlt)
summerX_new = np.linspace(summerX.min(), summerX.max(),30)
summerY_smooth = splev(summerX_new, splrep(summerX, summerY, k=1))
myMap.plot(summerX_new, summerY_smooth, 'g')
myMap.plot(summerX, summerY, 'go')
plt.show()
答案 0 :(得分:1)
此极坐标表示中的圆圈看起来不像矩形网格上的圆圈(即"圆形#34;)。除此之外,您可以像在笛卡尔平面上一样绘制圆,从极坐标开始,转换为笛卡尔坐标,偏移中心并使用绘图函数。
summerAzi = np.array([0, 360])
summerAlt = -np.array([40, 4])
summerX, summerY = myMap(summerAzi, summerAlt)
phi = np.linspace(0,2.*np.pi)
r = np.abs(np.diff(summerAlt))/2.
x = r*np.cos(phi)
y = -r*np.sin(phi)+summerAlt.mean()
X,Y= myMap(x,y)
myMap.plot(X,Y, color="crimson")
myMap.plot(summerX, summerY, color="gold", marker="o")
答案 1 :(得分:1)