如何在 Matlab 中绘制圆形而不是直线轴？

Question

我有一组 3 个数据集，我想在 MATLAB 中绘制，但是“x”轴，我想以圆形而不是直线的形式给出。有什么想法吗？

示例图：

在 MATLAB 中绘图的常规命令是plot(x, data1, x data2, x, data3)，其中 x 轴被视为直线。我希望将 x 轴视为一个圆圈。请问有谁知道它的命令。

Answer 1

@Alok 询问你是否想要一个极坐标图。我告诉你，你确实想要一个极地情节！有关函数 polar() 及其关系，请参见 Matlab 文档，例如 cart2pol。根据您的具体要求（我没有关注您的链接），您可能会发现制作您想要的情节相对容易或相当困难。

Answer 2

下面是一个完整的例子，展示了如何将数据从线轴映射到圆。

我展示了两种实现目标的方法：

• 三个数据系列重叠（即全部映射到同一范围）
• 另一种选择是将它们叠加绘制（在不同的相邻范围上）

基本思想：如果您有一个系列D，则将点映射到半径等于数据值的圆，使用：

theta = linspace(0, 2*pi, N);    %# divide circle by N points (length of data)
r = data;                        %# radius
x = r.*cos(theta);               %# x-coordinate
y = r.*sin(theta);               %# y-coordinate
plot(x, y, '-');

选项 1

%# some random data
K = 3;
N = 30;
data = zeros(K,N);
data(1,:) = 0.2*randn(1,N) + 1;
data(2,:) = 0.2*randn(1,N) + 2;
data(3,:) = 0.2*randn(1,N) + 3;

center = [0 0];                        %# center (shift)
radius = [data data(:,1)];             %# added first to last to create closed loop
radius = normalize(radius',1)'+1;      %# normalize data to [0,1] range

figure, hold on

%# draw outer circle
theta = linspace(5*pi/2, pi/2, 500)';  %# 'angles
r = max(radius(:));                    %# radius
x = r*cos(theta)+center(1);
y = r*sin(theta)+center(2);
plot(x, y, 'k:');

%# draw mid-circles
theta = linspace(5*pi/2, pi/2, 500)';  %# 'angles
num = 5;                               %# number of circles
rr = linspace(0,2,num+2);              %# radiuses
for k=1:num
    r = rr(k+1);
    x = r*cos(theta)+center(1);
    y = r*sin(theta)+center(2);
    plot(x, y, 'k:');
end

%# draw labels
theta = linspace(5*pi/2, pi/2, N+1)';    %# 'angles
theta(end) = [];
r = max(radius(:));
r = r + r*0.2;                           %# shift to outside a bit
x = r*cos(theta)+center(1);
y = r*sin(theta)+center(2);
str = strcat(num2str((1:N)','%d'),{});   %# 'labels
text(x, y, str, 'FontWeight','Bold');

%# draw the actual series
theta = linspace(5*pi/2, pi/2, N+1);
x = bsxfun(@times, radius, cos(theta)+center(1))';
y = bsxfun(@times, radius, sin(theta)+center(2))';
h = zeros(1,K);
clr = hsv(K);
for k=1:K
    h(k) = plot(x(:,k), y(:,k), '.-', 'Color', clr(k,:), 'LineWidth', 2);
end

%# legend and fix axes
legend(h, {'M1' 'M2' 'M3'}, 'location', 'SouthOutside', 'orientation','horizontal')
hold off
axis equal, axis([-1 1 -1 1] * r), axis off

选项 2

%# some random data
K = 3;
N = 30;
data = zeros(K,N);
data(1,:) = 0.2*randn(1,N) + 1;
data(2,:) = 0.2*randn(1,N) + 2;
data(3,:) = 0.2*randn(1,N) + 3;

center = [0 0];                                %# center (shift)
radius = [data data(:,1)];                     %# added first to last to create closed loop
radius = normalize(radius',1)';                %# normalize data to [0,1] range
radius = bsxfun( @plus, radius, (1:2:2*K)' );  %# 'make serieson seperate ranges by addition

figure, hold on

%# draw outer circle
theta = linspace(5*pi/2, pi/2, 500)';   %# 'angles
r = max(radius(:))+1;                   %# radius
x = r*cos(theta)+center(1);
y = r*sin(theta)+center(2);
plot(x, y, 'k:');

%# draw mid-circles
theta = linspace(5*pi/2, pi/2, 500)';  %# 'angles
r = 1.5;                               %# radius
for k=1:K
    x = r*cos(theta)+center(1);
    y = r*sin(theta)+center(2);
    plot(x, y, 'k:');
    r=r+2;             %# increment radius for next circle
end

%# draw labels
theta = linspace(5*pi/2, pi/2, N+1)';    %# 'angles
theta(end) = [];
r = max(radius(:))+1;
r = r + r*0.2;                           %# shift to outside a bit
x = r*cos(theta)+center(1);
y = r*sin(theta)+center(2);
str = strcat(num2str((1:N)','%d'),{});   %# 'labels
text(x, y, str, 'FontWeight','Bold');

%# draw the actual series
theta = linspace(5*pi/2, pi/2, N+1);
x = bsxfun(@times, radius, cos(theta)+center(1))';
y = bsxfun(@times, radius, sin(theta)+center(2))';
h = zeros(1,K);
clr = hsv(K);
for k=1:K
    h(k) = plot(x(:,k), y(:,k), '.-', 'Color', clr(k,:), 'LineWidth', 2);
end

%# legend and fix axes
legend(h, {'M1' 'M2' 'M3'}, 'location', 'SouthOutside', 'orientation','horizontal')
hold off
axis equal, axis([-1 1 -1 1] * r), axis off

---

我应该提到normalize() 是一个自定义函数，它只是执行最小最大归一化（(x-min)/(max-min)），定义为：

function newData = normalize(data, type)
    [numInst numDim] = size(data);
    e = ones(numInst, 1);
    minimum = min(data);
    maximum = max(data);
    range = (maximum - minimum);

    if type == 1
        %# minmax normalization: (x-min)/(max-min)   =>   x in [0,1]
        newData = (data - e*minimum) ./ ( e*(range+(range==0)) );
    end

    %# (...)
end

Answer 3

您可以找到here 所有可用的 MATLAB 2-D 和 3-D 绘图函数。

Answer 4

对不起，如果这可能不是您问题的正确答案（您已经有很多了）。我最近发现了一个非常强大的工具来绘制圆圈 - CIRCOS：http://mkweb.bcgsc.ca/circos/ 看看，数字真的很惊人。它不是基于 Matlab，而是基于 Perl，而且它是免费的。也许你会发现它很有用。