# Colour plot vs Time on a circle

7 ビュー (過去 30 日間)
Sankar Ram T 2020 年 5 月 25 日

I have temp vs time data for 100 points along a circle.
I would like create a small animation of the temp vs time basedon colour of the circle.
(If not a circle I would atleast like to try it along a line. )
Is it possible somehow?
A sample/Example would be like this
This has 6 frames, with the color representing the temperature and frames representing the passage of time.
Here it is made as a contiuous diagram, with smooth gradients. If it is not possible, is it possible as discreet sections of a circle.

#### 4 件のコメント

Sankar Ram T 2020 年 5 月 26 日
Geoff . Added a sample animation.
darova 2020 年 5 月 26 日
Sankar Ram T 2020 年 5 月 26 日
Coloum 1 is Time (Sec)
Rest are temperatures of 20 Sectors

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### 回答 (1 件)

Kelly Kearney 2020 年 5 月 26 日
It's not clear to me whether you've already created the circle plots in Matlab, or if you just sketched out your desire outcome.
If you haven't plotted them yet, I think using a simple patch is the easiest way to achieve that look. To animate, it depends on whether you just want to animate on screen or export to something like a gif. The example below shows the former.
% Some example data
t = linspace(0,1,100)'; % time coordinate, normalized
data = rand(100,3); % three time steps of random data
% Use patch to plot the circle
th = 2*pi*t;
rmin = 0.8; % inner radius
rmax = 1; % outer radius
xouter = rmax.*cos(th);
xinner = rmin.*cos(th);
youter = rmax.*sin(th);
yinner = rmin.*sin(th);
x = [xouter; xinner(end:-1:1); xouter(1)];
y = [youter; yinner(end:-1:1); youter(1)];
c = [data; data(end:-1:1,:); data(1,:)];
axes
p = patch(x,y,c(:,1));
axis equal;
set(gca, 'visible', 'off');
set(p, 'edgecolor', 'none');
% Loop over to animate
for it = 2:size(data,2)
pause(1);
set(p, 'cdata', c(:,it));
end

#### 3 件のコメント

Sankar Ram T 2020 年 5 月 29 日
Frankly, I didn't understand the code fully. I ran it and something is happening. I tried loading my own data and it was not working very well. It is plotting a circle and it is colouring it but it looks more like random patchs and not like each seperarte sectors haveing some colour.
I am trying to understand the code, but can you use the data I have attached above and see whether the code is working as intended?
Kelly Kearney 2020 年 5 月 29 日
Here's the example again, this time with your data and more comments:
data = table2array(tmp(:,2:end))'; % sector x time array
sector = 1:size(data,1); % sector, 1,2,...20
% Step 1: upsample your data. This isn't strictly necessary but will allow
% your ring to look more like a circle than a 20-gon
secup = linspace(1,20,100)';
data = interp1(sector, data, secup); % new higher-res sector x time array
% Step 2: Calculate x- and y-coordinates of the ring
secnorm = (secup - min(secup))./(max(secup)-min(secup)); % normalize sector...
th = 2*pi*secnorm; % ... and then convert to angle between 0 and 2*pi
rmin = 0.8; % inner radius
rmax = 1; % outer radius
xouter = rmax.*cos(th); % coordinates of outer ring (counterclockwise from right)
xinner = rmin.*cos(th);
youter = rmax.*sin(th); % coordinates of inner ring (counterclockwise from right)
yinner = rmin.*sin(th);
% ... to draw the ring, connect the outer circle counterclockwise, then the
% inner circle clockwise, and then back to the first point of the outer
% circle.
x = [xouter; xinner(end:-1:1); xouter(1)]; % ring x coords
y = [youter; yinner(end:-1:1); youter(1)]; % ring y coords
c = [data; data(end:-1:1,:); data(1,:)]; % color data corresponding to each vertex
% Prepare time label (just for reference)
tstr = cellstr(num2str(tmp.Time, '%6.4f')); % # time x 1 cell array
% Step 3: Plot using the color data for the first time step
axes;
p = patch(x,y,c(:,1)); % plot patch
axis equal; % set aspect ratio equal
set(gca, 'visible', 'off', 'clim', [0 1505]); % hide the axis box and ...
% set the color limits to match the data
t = text(0, 1.1, tstr{1}, 'horiz', 'center'); % Add a text label with the time
set(p, 'edgecolor', 'none'); % hide the edges of the patch
% Step: Loop to animate, changing color data and time label
for it = 2:size(data,2)
pause(0.01);
set(p, 'cdata', c(:,it));
set(t, 'string', tstr{it});
end
Sankar Ram T 2020 年 5 月 29 日
By the time I undersood your pevious code, you made a improved version. 👍👍
I had worked around the previos code to plot my data. I found 2 bugs.
1) The top of the image has a 'patch'. The colours are not uniform there. What would cause that?
(May be the vertices on outer and inner are not lining up corretly???)
2)There is a jump in colour towards the right side of circle. I believe it is the start of the patch. Any way to smoothen this out?
I will go through the 2nd set of code, and get back. THANK YOU for the prompt reply.

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