I'm trying to make a figure of a surface plot, and beneath the surface I wish to show the contour lines, but I want the contour to be at z = -1 instead of at the default value 0. I found a previous post about this problem here, but when I try the solution the contour is still at z = 0. Maybe it has something to do with the version of MATLAB I'm using, which is 2014b?
Any ideas on how to make it work?
The code I tried:
%# plot surface and contour
Z = peaks;
surf(Z), hold on
[~,h] = contourf(Z); %# get handle to contourgroup object
%# change the ZData property of the inner patches
hh = get(h,'Children'); %# get handles to patch objects
for i=1:numel(hh)
zdata = ones(size( get(hh(i),'XData') ));
set(hh(i), 'ZData',-10*zdata)
end
So, I couldn't really figure out to do it as proposed in the example I found and posted, but I found a way that works. What I ended up doing was basically this:
figure
hold on
surf(X,Y,Z+1);
contour(X,Y,Z);
zz = get(gca,'ZTick');
set(gca,'ZTickLabel',sprintf('%3.1f\n',zz-1));
This gets me the surf and contour in the same figure, but yields some problems with color mappings.
I figured out how to solve the problem with color mappings the user Kine faced. Note: I've done the following code on MATLAB R2015b:
offset = 0.5;
plotHandle = surfc(X1, Y1, Z1);
hold on;
% This line moves the surface up from its original location and increases the space between the surface and the contour plot
plotHandle(1).ZData = plotHandle.ZData + offset;
% However in doing so the color mappings are changed. So, the line below restores these mappings
plotHandle(1).CData = plotHandle.CData - offset;
% This line changes fills the contour plot
plotHandle(2).Fill = 'on';
grid on;
% The following lines draw critical areas on the contour line, as it was more readable in my case
axisHandle = gca;
ZHeight = axisHandle.ZLim(1);
plot3(X2, Y2, ZHeight, 'o', 'MarkerSize', 10, 'LineWidth', 1, 'Color', 'k', 'MarkerFaceColor', 'm');
plot3(Y2, X2, ZHeight, 'o', 'MarkerSize', 10, 'LineWidth', 1, 'Color', 'k', 'MarkerFaceColor', 'm');
hold off
I got the same problem.
And finally, I got the contourf on plane Z=-10.
My MATLAB version is
MATLAB Version: 8.5.0.197613 (R2015a)
hope the codes work 4 you
clear all
clc
[X,Y,Z] = peaks;
[~,hContour] = contourf(X,Y,Z,20,'edgecolor','none');
hContour.ContourZLevel = -10; % set the contour's Z position
view(44,30)
colormap(jet)
Related
I have the following figure, where I plotted two surfaces and I wanted to indicate the intersection of both of them. To do that, I did the following:
zdiff = z1-z2;
C = contours(x,y,zdiff,[0 0]);
xL = C(1, 2:end);
yL = C(2, 2:end);
zL = interp2(x, y, z1, xL, yL);
line(xL, yL, zL, 'Color', 'k', 'LineWidth', 2,'Linestyle','--'); hold on;
line(xL, yL, zeros(size(zL)), 'Color', 'k', 'LineWidth', 2); hold off;
Now, I want to plot the vertical surface between the actual intersection (dash line) and its projection over XY (solid line), but I cannot figure out how to do that. Any ideas?
Another really simple option:
dist = (diff(xL).^2+diff(yL).^2).^0.5; %distance between x,y
cdist = [0, cumsum(dist)]; %cumsum of the distance
area = trapz(cdist,zL); %The area
Why not calculating it manually?
Something like (untested):
Area = 0
for i=1:numel(xL)-1
base = sqrt( (xL(i)-xL(i+1))^2 + (yL(i)-yL(i+1))^2);
Area =Area + base * (zL(i) + zL(i+1))/2;
end;
maybe not pretty but its a oneliner it might do the trick. maybe you have to adjust the format as this code is for (1,N) vectors
xL=(1:100); %size 1 100
yL=(1:100) ;%size 1 100
zL=rand(1,100);%size 1 100
line(xL,yL,zL)
line(xL,yL,zeros(size(zL)))
hold on
surf(repmat(xL,100,1),repmat(yL,100,1),cell2mat(arrayfun(#(x,y) linspace(x,y,100)',zL,zeros(size(zL)),'UniformOutput',false)))
xL=sin((1:30)/10); % Data generation for test only. Use your data
yL=cos((1:30)/10); % Data generation for test only. Use your data
zL=2+xL.*yL; % Data generation for test only. Use your data
surf([xL;xL],[yL;yL],[zeros(size(zL));zL]); % plot the surface
In the following script I get the coordinates of and coins in an image, later they are plotted. How can I also add to the plot the centroid calculated using stat (in red, marked as X)?
Script:
clc;
clear;
I = imread('coins.png');
imshow(I)
BW = im2bw(I);
BW_filled = imfill(BW,'holes');
stat = regionprops(BW_filled,'centroid');
boundaries = bwboundaries(BW_filled);
for k=1:10
b = boundaries{k};
plot(b(:,2),b(:,1),'g','LineWidth',3);
hold on;
end
Add
plot(stat(k).Centroid(1), stat(k).Centroid(2), 'rx');
after
plot(b(:,2), b(:,1), 'g', 'LineWidth', 3);
hold on;
You can also apply any additional customisations to the centroid point like
plot(stat(k).Centroid(1), stat(k).Centroid(2), 'rx', 'LineWidth', 3);
Explanation
stat(k) will get the kth element of stat. stat(k).Centroid will extract the centroid as [x, y] and we can then reference the x coordinate of the centroid as stat(k).Centroid(1) and the y as stat(k).Centroid(2).
Alternative Improvements
Some improvements to your code that I would suggest are
Put close all at the top of the script. This will close all currently open figures
Add figure; hold on; before the for loop and remove hold on from within the for loop. Calling hold on; multiple times is redundant.
I want to place three scatter plots in the same figure window and have a legend that describes them. The scatter plots all load in the same window just fine, but the legend only recognizes the last series. In other words, the legend shows a red marker (the color for the last series) for each of its entries.
How do I make the legend recognize each scatter and not just the last one? I've tried a bunch of different things, and none of them seem to work. Thanks!
The picture is the plot for one of my datasets, note the legend.
s10 = scatter3(x1, y1, z1, 'b'); hold on;
s1 = scatter3(x2, y2, z2, 'g'); hold on;
s01 = scatter3(x3, y3, z3, 'r'); hold on;
legend([s10,s1,s01], {'10ms', '1ms', '0.1ms'})
% Every legend entry is red (pertains to the last series)
I can't reproduce the problem. Using your code above with random data seems to work (I did fix a typo, you need a comma after the first argument to legend):
x1 = rand(10, 1); y1 = rand(10, 1); z1 = rand(10, 1);
x2 = rand(10, 1); y2 = rand(10, 1); z2 = rand(10, 1);
x3 = rand(10, 1); y3 = rand(10, 1); z3 = rand(10, 1);
s10 = scatter3(x1, y1, z1, 'b'); hold on;
s1 = scatter3(x2, y2, z2, 'g'); hold on;
s01 = scatter3(x3, y3, z3, 'r'); hold on;
legend([s10,s1,s01], {'Series 10', 'Series 1', 'Series 01'})
For me this seems to be associated with the recent version of Matlab (R2015b); in this version I get the same problem as you with the legend entries showing only one color (in contrast to the other answers that can't reproduce the problem). But if I roll back to a previous version (R2010b), the problem goes away. I'm not sure if you have that option, but it might help diagnose the precise issue.
If the previous answer doesn't work, you can also exploit dynamic legends. This answer is what is inspiring this post: Dynamic Legend (Updates in every recursion). This is a rather undocumented feature but it does work very well. Basically, after each plot, you are able to dynamically update what the legend looks like without having to make one call to legend that has all of them together.
As such, try something like this. I'll borrow some of the previous answer's code to get me started:
x1 = rand(10, 1); y1 = rand(10, 1); z1 = rand(10, 1);
x2 = rand(10, 1); y2 = rand(10, 1); z2 = rand(10, 1);
x3 = rand(10, 1); y3 = rand(10, 1); z3 = rand(10, 1);
scatter3(x1, y1, z1, 'b', 'DisplayName', '10ms'); hold on;
legend('-DynamicLegend');
scatter3(x2, y2, z2, 'g', 'DisplayName', '1ms'); hold on;
legend('-DynamicLegend');
scatter3(x3, y3, z3, 'r','DisplayName', '0.1ms'); hold on;
legend('-DynamicLegend');
Call scatter3, then make sure that you use the 'DisplayName' flag and place what you would normally put in the appropriate legend spot. After each call to scatter3 after, you use the legend('-DynamicLegend'); command to signal to MATLAB that the legend entries will be forthcoming... you're going to specify them in the 'DisplayName' flag.
When you do that, this is the figure I get:
As a minor note, I can't reproduce your plot either. I get the same plot as the previous answer.
This issue is caused by a Matlab bug affecting version R2015b. It was fixed in R2016a. There is a bugreport here, which contains a patch and 3 alternative workarounds.
Here are the workarounds in case the link goes dead:
If you are unable to install the patch, there are three alternative workarounds:
If the CData of each scatter plot is an RGB triplet, then assign the MarkerEdgeColor or MarkerFaceColor of each scatter plot to the value of the CData:
s1 = scatter(1:10,1:10);
hold on
s2 = scatter(2:11,1:10);
s1.MarkerEdgeColor = s1.CData;
s2.MarkerEdgeColor = s2.CData;
legend('show');
Assign an RGB triplet to the MarkerEdgeColor or MarkerFaceColor of each scatter plot:
s1 = scatter(1:10,1:10);
hold on
s2 = scatter(2:11,1:10);
s1.MarkerEdgeColor = [0 0.4470 0.7410];
s2.MarkerEdgeColor = [0.8500 0.3250 0.0980];
legend('show');
Use this workaround when all the points within each scatter plot are the same color.
Call the legend function with two or more output arguments:
s1 = scatter(1:10,1:10,[],1:10);
hold on
s2 = scatter(2:11,1:10,[],26:35);
[h, ~] = legend('show');
Use this workaround when the points within each scatter plot are different colors.
I'm using Matlab to produce figures, and I'm wondering if there is a way to plot a zoomed region in a figure of the overall data?
I have scatter data plotted over one week, with the x-axis in hours, and I want to zoom into the first 3 hours, and display them within the main figure with the x-axis label of minutes.
The plotting code I have so far is as follows:
allvalsx = marabint(:,2)
allvalsy = marabint(:,5)
subvalsx = marabint(1:7,2);
subvalsy = marabint(1:7,2);
%% Plots the scatter chart.
sizemarker = 135
handle = scatter(allvalsx, allvalsy, sizemarker, '.')
figure(1)
axes('Position',[.2 .2 .2 .2])
handle2 = scatter(subvalsx, subvalsy, '.r')
title(plotTitle)
xlabel('Time since treatment (hours)')
ylabel('Contact angle (deg)')
% Axis scales x1, x2, y1, y2
axis([0, marabint(length(marabint),2) + 10, 0, 120]);
% This adds a red horizontal line indicating the untreated angle of the
% sample.
untreatedLine = line('XData', [0 marabint(length(marabint),2) + 10], 'YData', [untreatedAngle untreatedAngle], 'LineStyle', '-', ...
'LineWidth', 1, 'Color','r');
% Adding a legend to the graph
legendInfo = horzcat('Untreated angle of ', untreatedString)
hleg1 = legend(untreatedLine, legendInfo);
% This encases the plot in a box
a = gca;
% set box property to off and remove background color
set(a,'box','off','color','none')
% create new, empty axes with box but without ticks
b = axes('Position',get(a,'Position'),'box','on','xtick',[],'ytick',[]);
% set original axes as active
axes(a)
% link axes in case of zooming
linkaxes([a b])
set(gcf,'PaperUnits','inches');
set(gcf,'PaperSize', [8.267 5.25]);
set(gcf,'PaperPosition',[0 0.2625 8.267 4.75]);
set(gcf,'PaperPositionMode','Manual');
set(handle,'Marker','.');
print(gcf, '-dpdf', '-r150', horzcat('markertest4.pdf'));
This produces the following
Can anyone help me out with this?
yeah, I think I know what you need. Try this:
zoomStart = 0;
zoomStop = 3;
set(gca, 'XLim', [zoomStart zoomStop])
Let me know if that doesn't do what you need, and I'll give you a different way.
I want to plot 3D points in Matlab in different colors depending on a value. I've got following code, but this does not work because plot3d needs a vector.
x = vdhf_data.data(:,1);
y = vdhf_data.data(:,2);
z = vdhf_data.data(:,3);
data = vdhf_data.data(:,4);
grid on
hold all
for k=1:length(x)
if data(k) < 6
plot3d(x(k), y(k), z(k), 'ws--', 'MarkerEdgeColor', 'r', 'MarkerFaceColor', 'r')
else
plot3d(x(k), y(k), z(k), 'ws--', 'MarkerEdgeColor', 'g', 'MarkerFaceColor', 'g')
end
end
How to do that in Matlab?
I would use
scatter3(x,y,z,ones(size(x)),data,'filled')
This will plot all the points at the same size and color them according to the value of data, using the current colormap. You can also use data to scale the size of each point.
scatter3(x,y,z,data.^-2,data,'filled')