颜读（24）：Matlab学习之三维线图和text函数

摘要：plot3(x, y, z) 是 MATLAB 中用于绘制三维空间曲线或点集的核心函数，其功能类似于二维绘图中的 plot 函数，但增加了对z 轴数据的支持。x,y,z表示长度相同的向量或矩阵，表示点的三维坐标。

分享兴趣，传播快乐，

增长见闻，留下美好！

亲爱的您，这里是LearningYard学苑。

今天小编为大家带来

“颜读（24）：Matlab学习之三维线图和text函数”

欢迎您的访问！

Share interest, spread happiness,

increase knowledge, and leave beautiful.

Dear, this is the LearningYard Academy!

Today, the editor brings the

"Yan Du (24): MATLAB Learning: 3D Line Plots and the text Function "

Welcome to visit!

一、思维导图（Mind Mapping）

二、绘制三维线图（Draw a 3D line plot.）

（1）关键参数说明（Key Parameter Descriptions）

plot3(x, y, z) 是 MATLAB 中用于绘制三维空间曲线或点集的核心函数，其功能类似于二维绘图中的 plot 函数，但增加了对z 轴数据的支持。x,y,z表示长度相同的向量或矩阵，表示点的三维坐标。

The plot3 (x, y, z) function in MATLAB is the core function used for plotting 3D space curves or point sets. Its functionality is similar to the plot function in 2D plotting, but with added support for z-axis data. Here, x, y, and z represent vectors or matrices of the same length, indicating the three-dimensional coordinates of the points.

在 MATLAB 中，view 是一个用于控制三维图形的观察视角的函数，它决定了用户从哪个角度查看三维图形。通过调整视角，可以让数据呈现更直观的空间关系。接下来让我们来了解它的基本语法。view(azimuth, elevation)表示设置方位角和仰角，view([x, y, z])表示设置视线方向向量，view(2)表示切换为二维俯视图（XY平面），view(3)表示恢复默认三维视角。

In MATLAB, the view function is used to control the viewing perspective of 3D graphics, determining the angle from which the user views the 3D plot. By adjusting the perspective, you can make the spatial relationships of the data more intuitive. Next, let's explore its basic syntax. view(azimuth, elevation) sets the azimuth and elevation angles, view([x, y, z]) sets the viewing direction vector, view(2) switches to a 2D top-down view (XY plane), and view(3) restores the default 3D perspective.

在 MATLAB 中，grid on 是一个用于在图形中显示网格线的简单但强大的命令。它会在当前图形的坐标轴上添加灰色虚线网格，帮助用户更直观地判断数据点的位置和数值大小，可以使用 grid off 关闭网格。

In MATLAB, the grid on command is a simple yet powerful tool for displaying grid lines in a graph. It adds gray dashed grid lines to the current graph's axes, helping users more intuitively determine the positions and numerical values of data points. The grid can be turned off using the grid off command.

（2）绘图步骤（Steps for Plotting）

首先准备生成或定义三维曲线的坐标数据（X, Y, Z），使用plot3函数绘制三维线图，并自定义线条的形式，这里小编绘制一条螺旋线，如下图所示。

First, prepare or define the coordinate data (X, Y, Z) for generating a 3D curve. Use the plot3 function to draw the 3D line plot and customize the line style. Here, I will draw a helical curve, as shown in the following figure.

然后添加坐标轴的标签，将标题设置为“三维螺旋线”，同时使用grid on函数显示图形中的网格。

Then, add labels to the coordinate axes, set the title as "3D Helical Curve," and use the grid on function to display the grid lines in the graph.

最后我们可以使用view函数调整图形视角，这里调整到方位角30度，仰角45度。

Finally, we can use the view function to adjust the perspective of the graph. Here, we set the azimuth to 30 degrees and the elevation to 45 degrees.

三、text函数：在3D曲线上添加文本（text function: Add text to a 3D curve）

在MATLAB中，text 函数用于在图形中的指定位置添加文本注释。它可以用于二维（2D）和三维（3D）图形，允许用户自定义文本内容、位置、字体、颜色等属性。接下来我们应用上面绘制的三维线图，在曲线上的起点添加注释，设置好文本的字体大小和颜色，绘制结果如下图所示。

In MATLAB, the text function is used to add text annotations at specified positions within a graph. It can be applied to both two-dimensional (2D) and three-dimensional (3D) graphics, allowing users to customize attributes such as the text content, position, font, color, etc. Next, we will apply this to the 3D line plot we created earlier by adding a comment at the starting point of the curve, setting the font size and color of the text appropriately. The resulting plot is shown in the figure below.