如何在MATLAB中绘制第二个图形而不是颜色编码 [英] How to plot a second graph instead of color coding in matlab

问题描述

事情是，我在曲面上有一个轨迹一个行星/月球的任何东西（一个.mat随时间和坐标），然后我有一些.mat随着时间和当时的测量。

我是能够在散点图（）中将其绘制为颜色编码轨迹（使用测量和坐标），这非常棒。然而，我的问题是我需要一些东西更复杂
我现在需要采取轨迹，而不是颜色编码它，我应该添加测量（这是给每个点）的图形（价值）的轨迹（这不总是一条直线），我会添加一个小图来解释我想要的，红色箭头显示我想要添加到我的情节，绿色显示我有什么。

$ / $> $ / $> $ / $> $ / $> $ / $> b
$ b

  x = 0：0.1：10; 
 y = x; 
 m = 10 * sin（x）; 
  

因此，您需要的是每个数据点处的曲线法向量：

  dx = diff（x）; ％2向后有限差分：终点
 dx = [dx（1）dx]; ％第1点的正向有限差分
 dy = diff（y）; 
 dy = [dy（1）dy]; 
 curve_tang = [dx; DY]; 
％逆时针旋转切向90°
 curve_norm = [--dy; DX]; 
％对矢量进行归一化：
 nrm_cn = sqrt（sum（abs（curve_norm）。^ 2,1））; 
 curve_norm = curve_norm ./ repmat（sqrt（sum（abs（curve_norm）。^ 2,1）），2,1）; 
  

将该向量与测量值相乘（ m ），用数据点坐标抵消它，你就完成了：

  mx = x + curve_norm（1，：）。*米; 
 my = y + curve_norm（2，：）。* m; 
  

将其与以下图表合并：

 图。坚持
轴相等; 
 scatter（x，y，[]，m）; 
 plot（mx，my）
  

这正是您想要的。这个例子只有一条直线作为坐标，但是这段代码可以处理任何曲线：

  x = 0：0.1： 10; Y = X ^ 2; M =的sin（x）; 
  

$ b

  t = 0：pi / 50：2 * pi; x = 5 * cos（t） ; Y = 5 * SIN（T）; M = SIN（5 * T）; 
  

i just started with my master thesis and i already am in trouble with my capability/understanding of matlab.

The thing is, i have a trajectory on a surface of a planet/moon whatever (a .mat with the time, and the coordinates. Then i have some .mat with time and the measurement at that time.

I am able to plot this as a color coded trajectory (using the measurement and the coordinates) in scatter(). This works awesomely nice.

However my problem is that i need something more sophisticated. I now need to take the trajectory and instead of color-coding it, i am supposed to add the graph (value) of the measurement (which is given for each point) to the trajectory (which is not always a straight line). I will added a little sketch to explain what i want. The red arrow shows what i want to add to my plot and the green shows what i have.

解决方案

You can always transform your data yourself: (using the same notation as @Shai)

x = 0:0.1:10;
y = x;
m = 10*sin(x);

So what you need is the vector normal to the curve at each datapoint:

dx = diff(x); % backward finite differences for 2:end points
dx = [dx(1) dx]; % forward finite difference for 1th point
dy = diff(y);
dy = [dy(1) dy];
curve_tang = [dx ; dy];
% rotate tangential vectors 90° counterclockwise
curve_norm = [-dy; dx];
% normalize the vectors:
nrm_cn = sqrt(sum(abs(curve_norm).^2,1));
curve_norm = curve_norm ./ repmat(sqrt(sum(abs(curve_norm).^2,1)),2,1);

Multiply that vector with the measurement (m), offset it with the datapoint coordinates and you're done:

mx = x + curve_norm(1,:).*m;
my = y + curve_norm(2,:).*m;

plot it with:

figure; hold on
axis equal;
scatter(x,y,[],m);
plot(mx,my)

which is imo exactly what you want. This example has just a straight line as coordinates, but this code can handle any curve just fine:

x=0:0.1:10;y=x.^2;m=sin(x);

t=0:pi/50:2*pi;x=5*cos(t);y=5*sin(t);m=sin(5*t);

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