Python中的轮廓 [英] Contour in Python

问题描述

Z 的计算方式

from matplotlib.pyplot import contour

contour([X, Y,] Z, [levels], **kwargs)

绘制轮廓?

我知道 Z 的意思是:绘制轮廓的高度值.

但是是通过计算标准偏差还是类似的方法得出的?

But is it drawn by calculating a standard deviation or something like that?

我在每个点之间的平均值?

An average between each point I have?

推荐答案

Z 表示取决于 X 和 Y 轴的数量.如果 X 和 Y 表示一个平面，则可以将 Z 视为一个平面，其点高度取决于 X 和 Y 坐标.轮廓是该表面的顶视图"，即投影.一个例子是等高线，它们在经度( X )和纬度( Y )变化时报告山脉( Z )的高度.
在编写时， matplotlib 的 contour 函数绘制了 Z 变量(二维 numpy.ndarray(原样为 X 和 Y )，无需进一步处理. Z 和 X 和 Y 之间的关系在绘图函数外部定义.
我在下面举一个例子，也许可能有用:

Z represents a quantity dependent on both X and Y axes. If X and Y represent a plane, Z can be thought of as a surface, whose point height depends on the X and Y coordinates of that given point. The contour is a "top view" of that surface, a projection. An example are the contour lines which report the heights of the mountains (Z) as longitude (X) and latitude (Y) change.
The contour function of matplotlib, as you wrote it, plots the values expressed in the Z variable (two-dimensional numpy.ndarray, as X and Y) as they are, without further processing. The relationship between Z and X and Y is defined outside the plot function.
I report an example below which, perhaps it may be useful:

# IMPORT
import numpy as np
import matplotlib.pyplot as pl

# INPUT
N = 100
x_min = 0
x_max = 10
y_min = 0
y_max = 10
z_min = 0
z_max = 50
z_step = 1
red = '#de7677'

# DEFINE MESH GRID
x = np.linspace(x_min, x_max, N)
y = np.linspace(y_min, y_max, N)
XX, YY = np.meshgrid(x, y)

# CALCULATE ZZ AS A FUNCTION OF XX AND YY, FOR ESAMPLE, THEIR SUM
ZZ = YY + XX

# PLOT THE CONTOUR
fig, ax = pl.subplots(figsize = (10, 10))

cont = ax.contour(XX,
                  YY,
                  ZZ,
                  levels = np.arange(z_min, z_max + z_step, z_step),
                  colors = red)

# SET THE CONTOUR LABELS
pl.clabel(cont, fmt = '%d')

# SET THE X AND Y LABEL
ax.set_xlabel('X')
ax.set_ylabel('Y')

pl.show()

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