- 我怎样才能使任意meshgrid作为一个经常性的?
一个建议是创建一个规则的meshgrid,首先创建最小和最大x和y之间的均匀间隔值的数组。此外,您可以使用自定义滴答来反映您的数据点不是等距的事实。在代码中查看关于我如何实现该功能的评论。
- 如何使用彩色标记突出显示数据最高值的位置?
要检索的最高值,你可以使用np.max()
,然后找到该数据阵列np.where
在这个值的位置。只需在此位置绘制一个标记。
另外,使用plt.contour
你可以创建一个有足够接近最高值的位置的水平轮廓,以在其上创建它周围的环,或者甚至一个观点:
epsillon = 0.0001
levels = np.arange(max_value - epsillon, max_value + epsillon)
CS2 = plt.contour(X,Y,data, levels,
origin='lower',
linewidths=2,
extent=(-3,3,-2,2))
注意,与第一方法中,点将在现有网格节点的顶部结束,而plt.contour
会插值您的数据,并且根据所使用的插值算法,它可能会导致位置有所不同。然而在这里它似乎同意。
的代码:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib
def plot_s(data, x, y, xlist, ylist):
ax = plt.gca()
########### create your uniform meshgrid..... ############
X, Y = np.meshgrid(x, y)
CS = ax.contour(X, Y, data, colors='k')
###### ... and let ticks indicate that your new space is not linear
# assign tick positions according to the regular array
ax.set_yticks(y)
# Assign the label to reflect your original nodes position
ax.set_yticklabels(ylist)
# and same for x
ax.set_xticks(x)
ax.set_xticklabels(xlist)
#############################################################
########### GET MAXIMUM AND MARK IT WITH A POINT ########
# get maximum value in your data
max_value = np.max(data)
# get position index of this calue in your data array
local_max_index = np.where(data==max_value)
## retrieve position of your
max_x = X[local_max_index[0], local_max_index[1]]
max_y = Y[local_max_index[0], local_max_index[1]]
# plot one marker on this position
plt.plot(max_x, max_y, color="red", marker = "o", zorder = 10,
markersize=15, clip_on=False)
##############################################################
plt.title('Contour plot')
plt.show()
def main():
# Your data: 4 x 10 array
data = np.array([[ 0.56555019, 0.57933922, 0.58266252, 0.58067285, 0.57660236,
0.57185625, 0.56711252, 0.55557035, 0.55027705, 0.54480605],
[ 0.55486559, 0.57349717, 0.57940478, 0.57843897, 0.57463271,
0.56963449, 0.5643922 , 0.55095598, 0.54452534, 0.53762606],
[ 0.53529358, 0.56254991, 0.57328105, 0.57409218, 0.57066168,
0.5654082 , 0.55956853, 0.5432474 , 0.53501127, 0.52601203],
[ 0.50110483, 0.54004071, 0.55800178, 0.56173719, 0.55894846,
0.55328279, 0.54642887, 0.52598388, 0.51533094, 0.50354147]])
# create a list values with regular interval for the mesh grid
x = np.array([10 + i * (150.-10.)/9 for i in range(10)])
y = np.array([50 + i * (100.-50.)/4 for i in range(4)])
# create arrays with values to be displayed as ticks
xlist = np.array([10., 20., 30., 40., 50., 60., 70., 100., 120., 150.])
ylist = np.array([50, 70, 90, 100])
plot_s(data, x, y, xlist, ylist)
if __name__ == '__main__':
main()
瞧:
在这里,在后台的meshgrid显示变形/映射:
请注意,您不需要同时导入'pylab'和'numpy'。基本上'pylab'是'matplotlib'和'numpy'的简便组合。在脚本中,最好分别导入两个模块以确保每个方法的来源。 import matplotlib.pyplot as plt import numpy as np – Julien 2015-02-03 20:59:12