Matlab使用contourf

时间:2016-03-07 08:03:36

标签: matlab plot contourf

我在嵌套for循环中生成的矩阵中有数据。我想只绘制满足特定条件的数据(例如,它必须大于0.6)。数据点是否符合该条件在1矩阵中存储为0mlist

在Matlab中绘制此图的最简单方法是什么?对于不符合条件的数据点,它可以只是空格。

xlist = linspace(-1,1,20);
ylist = linspace(-2,2,30);

zlist = zeros(length(xlist),length(ylist));
mlist = zeros(length(xlist),length(ylist));

% iteration counter
ii = 0;
jj = 0;

for x = xlist
    ii = ii + 1;

    for y = ylist
        z = sin(x*y);
        jj = jj + 1;
        zlist(jj) = z;

        if z > 0.6
            mlist(jj) = 1;
        else
            mlist(jj) = 0;
        end
    end
end

contourf(ylist,xlist,zlist)

mesh(ylist,xlist,zlist)

2 个答案:

答案 0 :(得分:1)

在MATLAB中“删除”数据时,无需从数据中实际删除数据(因为您将遇到非均匀网格等问题)正在将其替换为NaN,如大多数MATLAB图将NaN视为缺失数据,并且不会在该点上绘制任何内容。

您可以将程序更改为不使用循环:

[x,y]=meshgrid(linspace(-1,1,20),linspace(-2,2,30));

z = sin(x.*y);
zlist(z<0.6)=NaN;
contourf(y,x,zlist); % // maybe x,y?

答案 1 :(得分:0)

我认为,最简单的方法是限制z轴:

xlist = linspace(-1,1,20);
ylist = linspace(-2,2,30);
zlist = zeros(length(xlist),length(ylist));
mlist = zeros(length(xlist),length(ylist));

% iteration counter
ii = 0;
jj = 0;

for x = xlist
    ii = ii + 1;
    for y = ylist
        z = sin(x*y);
        jj = jj + 1;
        zlist(jj) = z;
    end
end

contourf(ylist,xlist,zlist)
mesh(ylist,xlist,zlist)
zlim([0.6,max(z)])

为了增加可见性,我会考虑将contourf和mesh调用更改为:

surf(ylist,xlist,zlist)