在MATLAB中控制颜色条比例 [英] Control colorbar scale in MATLAB

问题描述

问题:如何在自定义MATLAB颜色栏中指定颜色过渡?
具体来说，我想使黄色(见下文)覆盖颜色栏的更多区域(可能[19.5–21.5]或接近该区域).

Question: How do I specify color transitions in a custom MATLAB colorbar?
Specifically, I'd like to make the yellow (see below) cover more area of the colorbar (perhaps [19.5–21.5] or something close to that).

使用这个答案，我能够在MATLAB中创建自定义颜色栏.我试图理解此答案，因为它可能是相关的.

Using this answer, I was able to create a custom colorbar in MATLAB. I'm trying to understand this answer as it might be relevant.

我尝试了此答案的方法，并回顾了此答案& 这一个，无法实现我的目标.

I have attempted approaches from this answer and reviewed this answer & this one and was unable to accomplish my goal.

很明显，我缺少了一些东西.

It is clear I am missing something.

下面的完整代表示例

% MATLAB 2017a
% Data
X = [22.6 22.8 22.6 20.45 22.3 18.15 19.95 20.8].';
Y = [84 89 63 81 68 83 77 52].';
Z = [23.0 22.695 21.1450 21.5 22.09 20.5 22.075 20.915].';

% Create custom colormap  
% Reference: https://stackoverflow.com/questions/24488378/how-to-map-a-specific-value-into-rgb-color-code-in-matlab/24488819#24488819
col3 = [0 1 0]; %G
col2 = [1 1 0]; %Y
col1 = [1 0 0]; %R
n1 = 20; n2 = 20;
cmap=[linspace(col1(1),col2(1),n1);linspace(col1(2),col2(2),n1);linspace(col1(3),col2(3),n1)];
cmap(:,end+1:end+n2)=[linspace(col2(1),col3(1),n2);linspace(col2(2),col3(2),n2);linspace(col2(3),col3(3),n2)];
cmap = cmap.';

% Plot
colormap(cmap), hold on, box on
p = scatter(X,Y,[],Z,'filled','DisplayName','Data3');
cb = colorbar;
cb.Limits = [18 23];
cb.Ticks = [18:1:23];

% Cosmetics
p.MarkerEdgeColor = 'k';
xlabel('X')
ylabel('Y')
cb.Label.String = 'Z';

推荐答案

我认为您所缺少的只是对

I think all that you're missing is a call to caxis to specify the minimum and maximum values to map the color range to:

caxis([18 23]);

请注意以下一行...

Note that the following line...

cb.Limits = [18 23];

...仅更改

... only changes the tick limits displayed on the colorbar, but doesn't change anything about how the data is mapped to the color range. The caxis function is how you control that (in the above case, mapping the value of 18 to one end and the value of 23 to the other). By default, your code was mapping the minimum and maximum values in Z to the color range (20.5 and 23, respectively). When you then set the tick limits on the color bar to a larger range, it just filled it in with the last color in the color map, in this case red. That's why you see so much of it.

仅仅因为您可能感兴趣，您还可以通过 interp1 函数可轻松生成您的颜色图，如下所示:

Just because you might be interested, you could also use interpolation via the interp1 function to easily generate your color map like so:

cmap = interp1([1 0 0; 1 1 0; 0 1 0], linspace(1, 3, 41));

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