I want to have each subplot share the same colorbar scale. I know caxis works for integers greater than 1, but there appears to be a problem using caxis with values such as 0.001.
x = 0:1:10;
y = 0:1:10;
z1 = .1:-.01:0;
z2 = .01:-.001:0;
figure;
subplot(1,2,1);
scatter(x,y,10,z1); colorbar;
subplot(1,2,2);
scatter(x,y,10,z2); colorbar;
Now I want to have the scatter subplots to have a common colorbar scale. I tried to use caxis, however I do not get the desired results. The left axis does not scale correctly, as they are all brown. How can this be corrected?
ca = [0 .01];
figure;
subplot(1,2,1);
scatter(x,y,10,z1); caxis(ca); colorbar;
subplot(1,2,2);
scatter(x,y,10,z2); caxis(ca); colorbar;
What you're seeing is the correct behaviour of caxis. When you set caxis([0 0.01]), all values greater than 0.01 are assigned the colour red (or brown, whatever you call it). In z1, all except the last point are greater than 0.01 and so they're all marked in red. If you tried caxis([0 0.1]), you'll see that the plot on the right is all blue.The dynamic range of your two subplots are an order of magnitude apart and so, you won't be able to represent both adequately with the same caxis limits.
Have you tried using a logarithmic color scale? Try the following:
subplot(1,2,1);
scatter(x,y,10,log10(z1)); colorbar;
caxis([-3 -1])
subplot(1,2,2);
scatter(x,y,10,log10(z2)); colorbar;
caxis([-3 -1])
Does the above plot look better?
Related
I need to make a plot with a discrete colorbar in Matlab. I do this in the following way:
data = randi(10, 20);
imagesc(data)
my_colormap = rand(10, 3);
colormap(my_colormap)
cb = colorbar
set(cb,'YTickLabel',{'A';'B';'C';'D';'E';'F';'G';'H';'I';'J';})
Now my problem is that the colorbar tick labels and the small lines in the colorbar don't align nicely. How can I even the colorbar tick labels and the small lines better as illustrated in the following pic:
The TickLabel on the colorbar each correspond to a value (a Tick). To place the TickLabels in the middle, you need to place the tick in the middle. To make this dynamic (so that It does not change when resizing the image) was I bit tricky I recall and I do not really recall. To set the ticks just once is not so hard though,
set(hCbar,'YTicks',RightYTicks);
EDIT:
On request I will post an example. This should give a hint of what to do.
x = 1:10;
y = 1:10;
cmap = jet(10);
[x, y] = meshgrid(x,y); %x and y grid
c = x-0.1; %Set color code to increase to the right
hFig = figure;
scatter(x(:),y(:),10,c(:),'filled'); % Simpler for the example
set(gca(hFig),'CLim',[0,10]);
colormap(cmap);
hCbar = colorbar;
set(hCbar,'YTicks',0.5:9.5);
set(hCbar,'YTickLabels',{'A','B','C','D','E','F','G','H','I','J'});
For newer matlab version, the YTicks may have changed name to Ticks And YTickLabels may be called TickLabels.
I am trying to create two y-axes plot in Matlab.
I have two groups of data, with each group having three plots of similar type. When I am trying to plot it, the scaling on right hand side y-axis get messed up. I would appreciate some help.
X = [50, 100, 200, 400];
YSKL_Temporal_WOFAE = [3.2000 2.3354 1.9428 1.7658];
YSKL_Spatial_WOFAE = [0.9225 0.9724 1.0986 1.1770];
YSKL_Spatial_WithFAE = [0.2635 0.1653 0.1513 0.1618];
YMSRE_Temporal_WOFAE = [0.3559 0.3027 0.2733 0.2636];
YMSRE_Spatial_WOFAE = [.3151 .2689 .2551 0.2524];
YMSRE_Spatial_WithFAE = [.0933 .0648 0.0663 0.0640];
figure(1);
[AX, p1, p2] = plotyy(X, YSKL_Temporal_WOFAE, X, YMSRE_Temporal_WOFAE);
set(AX,'XTick', X); % This fixes X-axis tick mark (same as data axis)
set(get(AX(1),'Ylabel'),'String','SKL Score')
set(get(AX(2),'Ylabel'),'String','Norm. Residuals')
xlabel('Time (\musec)')
title('SKL and Norm. Residual plotted on different y-axes')
set(p1,'LineStyle','--')
set(p2,'LineStyle',':')
axes(AX(1))
hold on
plot(X, YSKL_Spatial_WOFAE);
hold on
plot(X, YSKL_Spatial_WithFAE);
ylim([0 4])
hold off
axes(AX(2))
hold on
plot(X, YMSRE_Spatial_WOFAE);
hold on
plot(X, YMSRE_Spatial_WithFAE);
ylim([0.0 0.4])
hold off
Plot looks like this:
Please notice the scale on right y-axes
Regards,
Dushyant
The second (right hand side) y-axis tick labels are "frozen" after the call to plotyy. When adjusting the ylim on AX(2) this has no effect on the labels.
Therefore, the axes appearance has to be reset to auto.
Using the following code with the example from the question:
axes(AX(2))
hold on
plot(X, YMSRE_Spatial_WOFAE);
hold on
plot(X, YMSRE_Spatial_WithFAE);
ylim([0.0 0.4])
% include the following statement to allow
% the second y-axis to reset the ticks:
set(AX(2), 'YTickMode', 'auto', 'YTickLabelMode', 'auto')
hold off
Will yield this plot:
I have some points in a 'jet' colormap. The points have a coefficient that can go from 0 to 1, but usually they dont cover all the range, e.g 0.75-0.9.
When I plot those points I colour them so 0.75 is the lesser colour in the colormap and 0.9 is the maximum color in the colormap, so all the colormap is shown. What I want to do is show that in the colorbar also. When I plot the colorbar the labels on it go to 64, but I want them from 0.75 to 0.9. How can I do that?
EDIT
I don't think the code itself helps a lot but here it goes, just in case. In the colors variable I convert the ZNCC to the range of the colormap.
EDIT2
I found the reason why caxis is not working for me. Here is the code:
%this is why it doesnt work
im=imread('someimageyouwanttotest_inRGB.png')
imshow(im)
points=[1, 2;1 , 2 ;0.3,0.7]
ZNCC=points(3,:)
cmap=colormap('jet');
colors=cmap(round( ((1-min(ZNCC))+ZNCC-1).*(size(cmap,1)-1)/max((1-min(ZNCC))+ZNCC-1))+1,: );
hold on
for i=1:length(ZNCC)
plot(points(1,i),points(2,i),'.','Color',colors(i,:));
end
colorbar()
hold off
I think that is your code displays all your colours correctly then rather just set up the colour bar first on no image:
points=[1, 2;1 , 2 ;0.3,0.7]
ZNCC=points(3,:)
cmap=colormap('jet');
caxis([min(ZNCC) max(ZNCC)]);
colorbar();
hold on
%this is why it doesnt work
im=imread('someimageyouwanttotest_inRGB.png')
imshow(im)
colors=cmap(round( ((1-min(ZNCC))+ZNCC-1).*(size(cmap,1)-1)/max((1-min(ZNCC))+ZNCC-1))+1,: );
for i=1:length(ZNCC)
plot(points(1,i),points(2,i),'.','Color',colors(i,:));
end
hold off
I can't test it as I don't have imshow :/
If caxis is not working for you, you could store the return from colorbar - it is a handle to the colorbar object. Then you can set its properties, like 'YTick' and 'YLim'. The full list of properties you can set is the same as the Axes Properties (because the colorbar is just an axes object, after all).
Here is an example:
% Generate some random data
z = rand(10);
[x, y] = meshgrid(1:size(z, 1));
% Plot colour map
pcolor(x, y, z);
shading interp; % Comment out to disable colour interpolation
colormap jet;
% Setup colorbar
c = colorbar();
set(c, 'YTick', [0.75 0.875 1]); % In this example, just use three ticks for illustation
ylim(c, [0.75 1]);
It is only necessary to do this once, after you've finished plotting.
Edit: If you need the limits and ticks automatically from the data, then you can do something like
% Find the limits
lims = [min(z(:)) max(z(:))];
% Function for rounding to specified decimal places
dprnd = #(x, dps)round(x*(10.^dps))./(10.^dps);
% Generate ticks
nTicks = 5;
nDps = 2;
ticks = dprnd(linspace(lims(1), lims(2), nTicks), nDps);
set(c, 'YTick', ticks);
I am using plot3 to plot a matrix such that the resultant figure shows different colors for each vector of that matrix:
plot3(Grid.x1(:,:),Grid.x2(:,:),phi(:,:))
How can I smooth the coloring of this plot? Thanks!
You can use varycolor from FileExchange to construct and control a continuous range color spectrum. This way the transition between different lines will seem more natural and proximal lines will have similar colors.
You can read more and see examples usage here http://blogs.mathworks.com/pick/2008/08/15/colors-for-your-multi-line-plots/
Example:
[X,Y,Z] = peaks(128);
% raw plot3()
figure; plot3(X, Y, Z);
% define set equal to line number
ColorSet = varycolor(128);
% smooth plot3()
figure; hold all;
set(gca, 'ColorOrder', ColorSet);
plot3(X, Y, Z); view(3);
Update:
For a continuous 3D plot (i.e. a surface) you can use surfl instead of plot3 and display your data as a 3-D Surface Plot (with Shading). You can additionally apply any colormap on the resulting surface, i.e. gray or ColorSet as above.
surfl(X,Y,Z);
shading interp;
colormap(gray);
I was trying use the code shown below to plot in such a way that each iso-surface will be different in color and there will be a color bar at the right. I made a ss(k) color matrix for different colors. Number of iso-surfaces is 10 but I have only 8 colors. That's why I wrote ss(9)='r' and ss(10)='r'.
I need a solution to plot the iso-surface with different color and bar at the right side.
ss=['y','m','c','r','g','b','w','k','r','r']
k=1;
for i=.1:.1:1
p=patch(isosurface(x,y,z,v,i));
isonormals(x,y,z,v,p)
hold on;
set(p,'FaceColor',ss(k),'EdgeColor','none');
daspect([1,1,1])
view(3); axis tight
camlight
lighting gouraud
k=k+1;
end
Another possibility is to draw the patches with direct color-mapping (by setting the property 'CDataMapping'='direct'), while assigning the 'CData' of each patch to an index in the colormap of your choice. This is in fact recommended for maximum graphics performance.
Consider the following example:
%# volumetric data, and iso-levels we want to visualize
[x,y,z,v] = flow(25);
isovalues = linspace(-2.5,1.5,6);
num = numel(isovalues);
%# plot isosurfaces at each level, using direct color mapping
figure('Renderer','opengl')
p = zeros(num,1);
for i=1:num
p(i) = patch( isosurface(x,y,z,v,isovalues(i)) );
isonormals(x,y,z,v,p(i))
set(p(i), 'CData',i);
end
set(p, 'CDataMapping','direct', 'FaceColor','flat', 'EdgeColor','none')
%# define the colormap
clr = hsv(num);
colormap(clr)
%# legend of the isolevels
%#legend(p, num2str(isovalues(:)), ...
%# 'Location','North', 'Orientation','horizontal')
%# fix the colorbar to show iso-levels and their corresponding color
caxis([0 num])
colorbar('YTick',(1:num)-0.5, 'YTickLabel',num2str(isovalues(:)))
%# tweak the plot and view
box on; grid on; axis tight; daspect([1 1 1])
view(3); camproj perspective
camlight; lighting gouraud; alpha(0.75);
rotate3d on
I also included (commented) code to display the legend, but I found it to be redundant, and a colorbar looks nicer.
Matlab usually plots different iso-surfaces in different colors automatically, so you don't need to care about that. What kind of bar do you need? A colorbar or a legend? Either way, it is just to use the colorbar or legend function..
%Create some nice data
[x y z] = meshgrid(1:5,1:5,1:5);
v = ones(5,5,5);
for i=1:5
v(:,:,i)=i;
end
v(1:5,3:5,2)=1
v(1:5,4:5,3)=2
%Plot data
for i=1:5
isosurface(x,y,z,v,i)
end
%Add legend and/or colorbar
legend('one','Two','Three','Four')
colorbar
Since the color bar encodes value->color, it is impossible to do what you ask for, unless there is no intersection in z-values between all pairs of surfaces. So the solution below assumes this is the case. If this is not the case, you can still achieve it by adding a constant value to each surface, so to separate the surfaces along the z axis, and eliminate any intersection.
The solution is based on constructing a colormap matrix of piecewise constant values, distributed similarly to the z values of your surfaces. So for example, if you have 3 surfaces, the first has z values between 1 and 10, the 2nd between 11 and 30, and the 3rd between 31 and 60, you should do something like this (I plot in 2D for simplicity)
r = [1 0 0];
g = [0 1 0];
b = [0 0 1];
cmap = [r(ones(10,1),:); g(ones(20,1),:); b(ones(30,1),:)];
z1 = 1:10;
z2 = 11:30;
z3 = 31:60;
figure; hold on
plot(z1,'color',r)
plot(z2,'color',g)
plot(z3,'color',b)
colorbar
colormap(cmap)
More complex colormaps (i.e, more colors) can be constructed with different mixtures of red, green, and blue (http://www.mathworks.com/help/techdoc/ref/colorspec.html)