[matlab] 2.数据可视化

t=(0:0.01:2)*pi;
x=sin(t);
y=cos(t);
z=cos(2*t);
plot3(x,y,z,'r-','linewidth',1.5);
box on; %打开坐标系边框
legend('三维曲线作图');

x=0:0.2:1;
y=x;
[x y]=meshgrid(x,y);
plot(x,y,'b+')
%这就是所有(x,y)的取值 ,然后计算所有的z=f(x,y)就可以了

 

dd=0.001;n=1+1/dd;
[x,y]=meshgrid(0:dd:1,0:dd:1);
z=0;
for j=1:n
    for i=1:n
        if x(i,j)<sqrt(1-y(i,j).^2)
            z(i,j)=x(i,j).^2+y(i,j).^2;
        else
            z(i,j)=0;
        end
    end
end
surf(x,y,z);
shading flat;

 

附件链接( 密码ju5z ) 

下载附件 a.csv 给出了高程数据，共有 2913 列，2775 行

filename = 'a.csv';
z = csvread(filename);
x0=1:1:2775;
y0=1:1:2913;
[xx0,yy0]=meshgrid(x0,y0);
xx=xx0';%依题意 进行转置
yy=yy0';
figure
contourf(xx,yy,z,8)
saveas(gcf,['e:\','a','.png']); %无损存图

filename = 'a.csv';
z = csvread(filename);
y0=1:1:2913;
x0=1:1:2775;
[xx0,yy0]=meshgrid(x0,y0);
xx=xx0';%依题意 进行转置
yy=yy0';
contour(xx,yy,z,[1,3000],'r.') 
saveas(gcf,['e:\','test','.png']); %存图

filename = 'a.csv';
z = csvread(filename);
x0=1:1:2775;
y0=1:1:2913;
[xx0,yy2]=meshgrid(x0,y0);
xx=xx0';%依题意 进行转置
yy=yy0';

s=surf(xx,yy,z);
s.EdgeColor = 'none';
shading flat;

hold on
title('Contour map of the area');
xlabel('East(Degree)');
ylabel('South(Degree)');
hold off

saveas(gcf,['e:\','a','.png']); %存图 比gui存图 

 

function y = circle( x,y,r )
rectangle('Position',[x-r,y-r,2*r,2*r],'Curvature',[1,1],'linewidth',1),axis equal
end

[x, y] = meshgrid(1:10);            %构造测量网格
h = [0, 0.02, -0.12, 0, -2.09, 0, -0.58, -0.08, 0, 0;...
    0.02, 0, 0, -2.38, 0, -4.96, 0, 0, 0, -0.1;...
    0, 0.1, 1, 0, -3.04, 0, -0.53, 0, 0.1, 0;...
    0, 0, 0, 3.52, 0, 0, 0, 0, 0, 0;...
    -0.43, -1.98, 0, 0, 0, 0.77, 0, 2.17, 0, 0;
    0, 0, -2.29, 0, 0.69, 0, 2.59, 0, 0.3, 0;...
    -0.09, -0.31, 0, 0, 0, 4.27, 0, 0, 0, -0.01;...
    0, 0, 0, 5.13, 7.4, 0, 1.89, 0, 0.04, 0;...
    0.1, 0, 0.58, 0, 0, 1.75, 0, -0.11, 0, 0;...
    0, -0.01, 0, 0, 0.3, 0, 0, 0, 0, 0.01];          %测量数据点
[xi, yi] = meshgrid(1:0.01:10);               %构造插值网格
hi = griddata(x, y, h, xi, yi, 'v4');             %griddata进行V4插值
surf(hi);                                 %画出地貌
shading flat;                           %去除网格线
colorbar;                                   
xlabel('x'), ylabel('y'), zlabel('h')

未经插值的原图是

MATLAB RGB数值

 

 

figure
ax1 = subplot(2,1,1);
x = linspace(0,10,50);
y1 = sin(2*x);
plot(ax1,x,y1)
title(ax1,'Subplot 1')
ylabel(ax1,'Values from -1 to 1')

ax2 = subplot(2,1,2);
y2 = rand(50,1);
scatter(ax2,x,y2)
title(ax2,'Subplot 2')
ylabel(ax2,'Values from 0 to 1')

使用 subplot 函数在一个图窗中创建多个坐标区，该函数可将图窗划分为若干个子图网格。

例如，创建两个堆叠子图，并将 Axes 对象赋给变量 ax1 和 ax2。在每个子图中添加绘图、标题和轴标签。指定 Axes 对象作为每个 graphics 函数的第一个输入参数，以确保此函数以正确的坐标区为目标。