清空筛选条件
清空筛选条件

Meshgrid - RGB triplet plots

1 次查看（过去 30 天）
dave epic
dave epic 2015-9-9
评论： dave epic 2015-9-10
I'm trying to plot data in polar coordinates mapped to RGB data.
Using a standard xy axis this is trivial, but I can't seem to plot a mesh grid with RGB triplets in the same way. Below is a working example. Figure 1 displays the data in a Cartesian grid (theta vs. rho), with the color axis represented by RGB triplets.
Figure 2 displays the meshgrid following the polar to Cartesian grid transformation - but I have only plotted the intensity of the red (R) value.
Please could somebody advise on the line of script that will allow me to plot the semi-circle shown (Figure 2) with RGB values, not intensity as in the example.
Thanks in advance.
%
clear all; close all;
theta = linspace(0,pi,18);
rho = linspace(0,pi/2,9);
C(:,:,1) = rand(numel(theta),numel(rho));C(:,1,1) = 0.5;
C(:,:,2) = rand(numel(theta),numel(rho));C(:,1,2) = 0.5;
C(:,:,3) = rand(numel(theta),numel(rho));C(:,1,3) = 0.5;
figure(1)
imagesc(theta,rho,C)
xlabel('theta');ylabel('rho');
[TH,R] = meshgrid(theta,rho);
[X,Y] = pol2cart(TH,R);
figure(2)
surf(X,Y,C(:,:,1)') % this is only the values of the R triplet
xlim([-pi/2 pi/2]);ylim([-pi/2 pi/2]);
axis square
view(0, 90)

请先登录，再回答此问题。

采纳的回答

arich82
arich82 2015-9-9
I'm not entirely sure how your actual data is formatted, but your dummy data for C needs to transpose the theta and rho dimensions to agree with meshgrid's output.
Also, to specify C as an RGP triplet to surf, I think you must explicitly pass the Z argument.
See if the below can be adapted to your needs:
clear;
rng(1);
theta = linspace(0,pi,18);
rho = linspace(0,pi/2,9);
z = 0; % define z explicitly
C = rand(numel(rho), numel(theta), 3); % transpose oringinal rho and theta dims
%
figure(1)
imagesc(theta,rho,C)
xlabel('theta');ylabel('rho');
%
[TH,R,Z] = meshgrid(theta,rho,z);
[X,Y] = pol2cart(TH,R);
figure(2)
surf(X,Y,Z,C) % specify Z explicity to use C as RGB triplet
xlim([-pi/2 pi/2]);ylim([-pi/2 pi/2]);
axis square
view(0, 90)
  2 个评论
Walter Roberson
Walter Roberson 2015-9-9
Or a little more compactly,
surf(X,Y,zeros(size(X)),'CData',permute(C,[2 1 3]))
view([0 90])
axis equal
dave epic
dave epic 2015-9-10
Both of these are great solutions. Thanks.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Surface and Mesh Plots 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by