I've (single) 3430X6906 matrix having only zeros and ones and I want to scatter plot it. Suppose I've 1 on column 30 and row 40, the plot should have dot on point (30,40).
Can you please help me to plot it.
You want to get the row and column using find and then plot these using plot.
%// Create artificial data
data = rand(3430, 6906) > 0.99999;
%// Find the location of the ones
[row, col] = find(data);
%// Plot these locations
plot(col, row, 'o')
Related
I'm very new to Matlab. I'm trying to plot X, where X is an 100x1 vector, against Y, which is an 100x10 matrix. I want the result to be X vs 10 different Y values all in the same graph, different colors for each column. The only way I can think of plotting each column of this matrix is by using the hold command, but then I have to split it up so I get each column individually. Is there an easy way to do this?
Use repmat to expand X to be the same size as Y. Try plotting them with plot(X,Y) and if it looks strange, transpose each one (plot(X',Y')).
You can use linespec arguments to select linestyle, marker style, etc. For example, plot(X,Y,'.') would indicate a point at each vertex with no connecting lines.
You don't need to use repmat, just use plot instead of scatter:
plot(X,Y,'o')
Here's an example:
% some arbitrary data:
X = linspace(-2*pi,2*pi,100).'; % size(X) = 100 1
Y = bsxfun(#plus,sin(X),rand(100,10)); % size(Y) = 100 10
% you only need the next line:
plot(X,Y,'o')
legend('show')
Given the following code, how would one make the Inf values invisible in the scatter plot without color manipulation?
J = rand(20, 40, 5);
J(J>.6 & J<.4) = Inf;
% Plot a scatter matrix
shape = size(J);
[x,y,z] = meshgrid(1:shape(1), 1:shape(2), 1:shape(3));
scatter3(x(:), y(:), z(:), 4, J(:), 'fill');
Data that have NaN values are made invisible when plotting with MATLAB, which you can exploit in your case. Since you want to make the Infinte values as invisible, you can convert all those to NaNs and then plot them. Here you can take help of logical indexing to index into Inf element positions. Thus, the code would be -
J(isinf(J))=NaN
%// ... Plot J
One method could be to change the values higher than a certain threshold to NaN (or any other number). I believe NaN values will not show up in your scatter plot. You can do this with the same code you are already using.
J(J>10^6) = NaN;
So I'm still getting used to Matlab and am having a bit of trouble with plotting. I have a cell which contains a list of points in each row. I want to plot each row of points in a different colour on the same graph so I can compare them. The catch is that I need to make this work for an unknown number of points and rows (ie the number of points and rows can change each time I run the program).
So for example, I might have my cell array A:
A = {[0,0], [1,2], [3,4]; [0,0] [5,6], [9,2]}
and I want to plot the points in row 1 against their index (so a 3D graph) and then have the points in row 2 on the same graph in a different colour. The rows will always be the same length. (Each row will always have the same number of points). I've tried a few different for loops but just can't seem to get this right.
Any help in sending me in the right direction would be greatly appreciated!
The fact that the number of points and rows can change with each iteration should not pose much of a problem. I would suggest using the size function before your plot loops (size(A,1) and size(A,2)) to get the dimensions of the matrix.
Once you have the size of the matrix, loop through the dimensions and plot the lines on the same plot using holdon, and then finally just make the line color a function of the dimensions as you loop through so that you always have a different line color
You could just convert it to a matrix and plot it directly:
% Some dummy data - format a little different from your example
% to allow for different numbers of elements per row
A = {[0,0, 1,2, 3,4]; [0,0, 5,6]};
% Figure out how many columns we need in total
maxLen = max(cellfun(#length, A));
% Preallocate
Amat = NaN(size(A, 1), maxLen);
% Copy data
for n = 1:size(A, 1)
curA = A{n};
Amat(n, 1:length(curA)) = curA;
end
% Generate 1:N vector repeated the correct number of times (rows)
x = repmat(1:size(Amat, 2), size(Amat, 1), 1);
plot(x, Amat)
Edit: You mentioned a 3D graph at some point in your post. The above won't plot a 3D graph, so here's something that will:
% Generate Amat as above
% Then:
[X, Y] = meshgrid(1:size(Amat, 1), 1:size(Amat, 2));
surf(X, Y, Amat.'); % OR: plot3(X, Y, Amat.');
I'm not sure this is exactly what you want, but your question is slightly unclear on exactly what kind of graph you want out of this. If you just want coloured lines on your plot, you can use plot3 instead of surf, but IMHO surf will probably give you a clearer plot for this kind of data.
I want to plot 3D surface plots (which look like mountains). My data are square matrices. I want to be able to label the data where there is kind of a big cliff.
How can I go about it? Thanks
For a single 2D matrix you can use SURF function to plot 3D surface:
% generate random square 2D matrix 20x20
x = rand(20);
% make some (10) mountains
x(randi(numel(x),10,1))=rand(10,1)+5;
% plot surface
surf(x)
How do you want to plot multiple surfaces? On a single figure?
To label the large points lets threshold the data:
cutvalue = 1;
iHigh = find(x(:) > cutvalue);
[irow,icol] = ind2sub(size(x), iHigh);
hold on
plot3(icol, irow, x(iHigh), 'ro')
hold off
I am currently a begineer, and i am using matlab to do a data analysis. I have a a text file with data at the first row is formatted as follow:
time;wave height 1;wave height 2;.......
I have column until wave height 19 and rows total 4000 rows.
Data in the first column is time in second. From 2nd column onwards, it is wave height elevation which is in meter. At the moment I like to ask matlab to plot a 3d graph with time on the x axis, wave elevation on the y axis, and wave elevation that correspond to wave height number from 1 to 19, i.e. data in column 2 row 10 has a let say 8m which is correspond to wave height 1 and time at the column 1 row 10.
I have try the following:
clear;
filename='abc.daf';
path='C:\D';
a=dlmread([path '\' filename],' ', 2, 1);
[nrows,ncols]=size(a);
t=a(1:nrows,1);%define t from text file
for i=(1:20),
j=(2:21);
end
wi=a(:,j);
for k=(2:4000),
l=k;
end
r=a(l,:);
But everytime i use try to plot them, the for loop wi works fine, but for r=a(l,:);, the plot only either give me the last time data only but i want all data in the file to be plot.
Is there a way i can do that. I am sorry as it is a bit confusing but i will be very thankful if anyone can help me out.
Thank you!!!!!!!!!!
Once you load your data as you do in your code above your variable a should be a 4000-by-20 array. You could then create a 3-D plot in a couple of different ways. You could create a 3-D line plot using the function PLOT3, plotting one line for each column of wave elevation data:
t = a(:,1); %# Your time vector
for i = 2:20 %# Loop over remaining columns
plot3(t,(i-1).*ones(4000,1),a(:,i)); %# Plot one column
hold on; %# Continue plotting to the same axes
end
xlabel('Time'); %# Time on the x-axis
ylabel('Wave number'); %# Wave number (1-19) on y-axis
zlabel('Wave elevation'); %# Elevation on z-axis
Another way to plot your data in 3-D is to make a mesh or surface plot, using the functions MESH or SURF, respectively. Here's an example:
h = surf(a(:,1),1:19,a(:,2:20)'); %'# Plot a colored surface
set(h,'EdgeColor','none'); %# Turn off edge coloring (easier to see surface)
xlabel('Time'); %# Time on the x-axis
ylabel('Wave number'); %# Wave number (1-19) on y-axis
zlabel('Wave elevation'); %# Elevation on z-axis
I don't quite understand what your function does, for example, I do not see any plot command.
Here's how I'd try to make a 3D plot according to your specs:
%# Create some data - time from 0 to 2pi, ten sets of data with frequency 1 through 10.
%# You would just load A instead (I use uppercase just so I know that A is a 2D array,
%# rather than a vector)
x = linspace(0,2*pi,100)';%#' linspace makes equally spaced points
w = 1:10;
[xx,ww]=ndgrid(x,w); %# prepare data for easy calculation of matrix A
y = ww.*sin(xx.*ww);
A = [x,y]; %# A is [time,data]
%# find size of A
[nRows,nCols] = size(A);
%# create a figure, loop through the columns 2:end of A to plot
colors = hsv(10);
figure,
hold on,
for i=1:nCols-1,
%# plot time vs waveIdx vs wave height
plot3(A(:,1),i*ones(nRows,1),A(:,1+i),'Color',colors(i,:)),
end
%# set a reasonable 3D view
view(45,60)
%# for clarity, label axes
xlabel('time')
ylabel('wave index')
zlabel('wave height')
Or, you could try gnuplot. Fast, free and relatively easy to use. I use it to generate heat maps for datasets in the millions of rows.