I have measured values in different times and I would like to plot them.
In the excel file the columns are separated for the time and for the values. The time format is : HH:MM:SS e.g:11:20:21.
I wolud like to plot on the x axis the diferrence between the times (in seconds).The y axis would be the measured values. I read the datas from the excel file but don't know how to plot the x axes.
For example: datas in excel:10:20:33,10:20:35,10:20:39 and on the x axes the values are:0,2,4 (in seconds).
Here is my start:
V1= xlsread('measured.xlsx','D4:D5295')
V2= xlsread('measured.xlsx','E4:E5295')
CV= xlsread('measured.xlsx','F4:F5295')
t=xlsread('measured.xlsx','B4:B5295')
plot(t,V1,t,V2,t,CV)
datetick('x',13)
title('Measurement')
ylabel('Data [V]')
xlabel('time [s]')
With this I get on the x axis date but I would like to get the elapsed time between two measuretime.
What I will do is convert the time vector to "datatime" data type, calculate the difference between the times (using the diff command) and then convert it to seconds.
V1= xlsread('measured.xlsx','D4:D5295')
V2= xlsread('measured.xlsx','E4:E5295')
CV= xlsread('measured.xlsx','F4:F5295')
t=xlsread('measured.xlsx','B4:B5295')
% convert it to datatime data type
t = datetime(t);
% Get the difference between times and add the "0" to keep
% the same vector size.
t = [0; seconds(diff(t))];
plot(t,V1,t,V2,t,CV)
datetick('x',13)
title('Measurement')
ylabel('Data [V]')
xlabel('time [s]')
Related
I have created a matlab GUI that plot a graph.
I have a few issues;
I cannot change the date format using datetic.
I cannot eliminate scientific notation from plot.
I have a 2nd plot that I wan to add to add as a 2nd Y axis. The x axis are the same.
I my original live script I could plot on 2nd y axis using the yyaxis right and yyleft commands.
These do not work in GUI??
The current GUI
% Code that executes after component creation
function startupFcn(app)
load covid_data.mat
% Code to summ all cumlative data at Global Level and plot
[R,C]=size(covid_data);
for i=1:R-1
for j=1:C-3
% Read cumulative case count covid into array of specified row
CumCases(i,j) =covid_data{i+1,j+2}(1,1);
CumDeaths(i,j) =covid_data{i+1,j+2}(1,2);
end
end
SumAllCumCase=sum(CumCases);
SumAllDeaths=sum(CumDeaths);
% Create vector of dates for use in plot bar charts
%datenum converts string to numeric date
for i=1:C-3
Date(i) =datenum(covid_data{1,i+2});
end
x = Date;
dateFormat = 6;
datetick('x',dateFormat);
app.SumAllCase = SumAllCumCase
app.SumAllDeath = SumAllDeaths
app.Dates=x
plot(app.UIAxes,app.Dates,app.SumAllDeath)
% plot(app.UIAxes,app.Dates,app.SumAllCase)
I have a code which goes like this:
clc;clear;close all
%%
Time=linspace(16.8,17.8,230400)';
Field=linspace(50,145,230400)';
figure('units','normalized','outerposition',[0 0 1 1])
plot(Time,Field)
%%
figure('units','normalized','outerposition',[0 0 1 1])
hammng_wndw_size=4096;
window=hamming(hammng_wndw_size); %window size
noverlap=512; % the noverlaps its the no. of points for repeating the window
nfft=4096; %size of fft
fs=32; %sampling freq
[Sp,F,T,P]=spectrogram(Field,window,noverlap,nfft,fs,'yaxis');
T_forspectrogrm=T./3600+Time(1);
surf(T_forspectrogrm,F,10*log10(P),'edgecolor','none','FaceColor','interp');
axis tight;ylim([0 4]);view(0,90);
colormap(jet);colorbar;
The result of this plot is these two figures:
The xaxis is time and y axis is some other quantity, lets say field. Now, when I plotting, the x axis starts from 16.8 to 17.8 for first figure and 16.8 and 18.8 for second figure. This actually corresponds to 16:48:00 to 17:48:00 and similarly for the second one. How do I have to modify the program to convert the x-axis into hh:mm format do this job?
I tried in this fashion
TimeInReqFrmat=datestr(Time(:,1),'HH:MM:SS'), but this gives me a string of characters.
I am using Matlab 2016a.
Thanks in advance
You approach was almost right. You need to use datetimes. It's just a bit tricky to convert decimal numbers to date times
x = [16.8;17.8]
H = floor(x); % hour
m = floor((x-H)*60); % minute
S = (x-H)*60-m; % second
% create date vector
DateVec = datetime(0,0,0,H,m,S);
plot(DateVec,rand(size(DateVec)))
% set the tick format
xtickformat('HH:mm')
There are many options to set the xtickformat.
If you have unix-time, you can convert it right away
datetime(x,'ConvertFrom','datenum')
If you have just time, you will need to come up with a date for a proper datetime. Otherwiese you can also think of using duration.
I have a (1x700) vector x for which I would like to create and plot a time series object in Matlab. Each observation corresponds to one month, and the first observation belongs to January 1960. I tried the following:
state1 = timeseries(x,1:size(x,2));
state1.Name = 'Test';
state1.TimeInfo.Units = 'months';
state1.TimeInfo.StartDate = 'Jan-1960'; % Set start date.
state1.TimeInfo.Format = 'yy'; % Set format for display on x-axis.
state1.Time = state1.time - state1.time(1); % Express time relative to the start date.
plot(state1);
However, I still see numbers on the x-axis instead of years. Could anyone please help? Thanks in advance!
Create random data. 1/12 corresponds to the fraction of a year that each month represents.
x = 1960:1/12:1970;
y = rand(1,121);
Then plot the x and y axes data using plot.
plot( x, y )
Then set the tick as follows for a decade per year. 1960:1970 will generate [1960 1961 ...] each corresponding to the tick's year.
set( gca, 'XTick', 1960:1970 );
Here is the output plot.
Doing 1 year intervals get VERY MESSY with lots of data. So solutions include doing a larger interval or setting your ticks to display vertically instead of horizontally. This code below shows how to set 5 year intervals instead.
set( gca, 'XTick', 1960:5:2010 );
what is the best way to merge and plot 2 (or more) time stamped data so that the plot includes the gaps between the known data?
For example, I have a cell with time and heart rate values for Monday, and another for Friday. I would like to plot all data from Mon to Friday which includesthe gaps showing nothing was recorded from Tues-Thurs?
So far if I merge the data
data = [mon;fri]
% get the time serial numbers
dateInd = 1;
dateString = data(dateIndex);
dateFormat = 'dd/mm/yyyy HH:MM:SS';
tNum = datenum(dateString{1},dateFormat);
t = linspace(tNum(1),tNum(end),length(tNum));
% get heart rates,
HRIndex = 2;
HR = data(HRIndex);
and plot
plot(t,HR)
datetick('x','ddd');
I obviously get Monday and Fridays data merged into a single plot 2 days long. but I would like to have a plot 5 days long with data only showing on monday and Friday. What is the best way to achieve this?
I hope this makes sense,
Many thanks,
Jon
To achieve such effect I usually fill missing data with NaNs, like here:
x = linspace(0,2*pi,100);
y = sin(x);
y(20:30) = NaN; % there will be a gap from point#20 to point#30
plot(x,y);
The reason is that MatLab does not draw plot points where either x or y data are NaNs.
In your case you may add missing time points to your time data (to have corect gap) and NaNs to corresponding Y-values.
By the way, why don't you plot two separate plots with X-data of the second one properly shifted?
EDIT
Case 1: your x-data is time relative to the start of the day (in 0-24 interval). If you plot them directly they will overlap. You have to add some offset manually, like this:
% generate test data
x1 = linspace(0,1,25); % 25 points per first day
y1 = rand(25,1);
x2 = linspace(0,1,25); % 25 points per second day
y2 = rand(25,1);
% plot them as two separate plots
% so line style, color, markers may be set separately
XOffset = 3;
figure;
plot(x1,y1,'*k-', x2+XOffset,y2,'*r-');
% plot them as single separate plot
% so line style, color, markers are the same
figure;
plot([x1(:); NaN; x2(:)+XOffset],[y1(:); NaN; y2(:)],'*k-');
% One NaN is enough to insert a gap.
Case 2: your x-data have full time information including the date (like MatLab's serial date number, see help on now function, for example). Then just plot them, they will be offset automatically.
% generate test data
XOffset = 3;
x1 = linspace(0,1,25); % 25 points per first day
y1 = rand(25,1);
x2 = linspace(0,1,25)+XOffset; % 25 points per second day, with offset
y2 = rand(25,1);
% plot them as two separate plots
% so line style, color, markers may be set separately
figure;
plot(x1,y1,'*k-', x2,y2,'*r-');
% plot them as single separate plot
% so line style, color, markers are the same
figure;
plot([x1(:); NaN; x2(:)],[y1(:); NaN; y2(:)],'*k-');
% One NaN is enough to insert a gap.
Also instead of
plot(x1,y1,'*k-', x2,y2,'*r-');
you may do like this (number of plots is not limited):
hold on;
plot(x1,y1,'*k-');
plot(x2,y2,'*r-');
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.