Plotting date (number) on x-axis

I want to plot all the day numbers on x-axis. I have really big timeseries data with 10-min wind speed averages, starting from 1st April and ending 30th April. I want to plot the wind speed, measured every 10min during the day, for the whole month. And on the x-axis I want to have ticks for every day starting from 1 till 30. Here is the code:

%% direct timetable importing
clc
clear

load april.mat %april timetable

dnum = day(ex1.timestamp);
mnum = month(ex1.timestamp);
myear = year(ex1.timestamp);

myear = unique(myear);      %finding year
mnum = unique(mnum);        %fingind month number
dlast = unique(max(dnum));  %finding last day

duniq = unique(dnum);
duniq = num2cell(duniq);

plot(ex1.timestamp,ex1.CH1Avg)
hAx = gca;

xlim(datetime([myear myear],[mnum mnum],[1 dlast])); %setting limits

xticklabels(duniq); %setting ticks to 30 like the number of days in April
 
datetick('x','dd'); %using date ticks, not working when trying dd

When i use in datetick('x','d') it is working. But when i use datetick('x' ,'dd') -it is not working. I also tried with datetick('x','d','keepticks'), but not working properly.

Can someone please help me?

Like it is shown on screenshot I want on x axis to have evenly distributed ticks for every day, starting from 01,02... ending at 30. like it is set in xlim

Answer 1

[Star Strider]

It is necessary to be creative with the plot and the tick labels.

Try this:

DL = load('april.mat');
ex1 = DL.ex1;
Q1 = ex1(1:10,:);

monthinfo = ex1.timestamp(1);
daylim = eomday(year(monthinfo),month(monthinfo));

figure
plot((1:size(ex1,1)),ex1.CH1Avg)
xt = get(gca,'XTick');
set(gca,'XTick',linspace(min(xt),max(xt),daylim), 'XTickLabel',compose('%02d',(1:daylim)))

Experiment to get the result you want.

[Gligor Terziev]

This is how I fixed.

clc
clear

load april.mat %creates timetable directly

 start1 = '01.04.2011 21:00:00';
 end1 = '30.04.2011 23:59:00';

startdate = datetime(start1,'InputFormat','dd.MM.yyyy HH:mm:ss');
enddate = datetime(end1,'InputFormat','dd.MM.yyyy HH:mm:ss');

 getrows = isbetween(ex1.timestamp, startdate, enddate);


dnum = day(ex1.timestamp);
mnum = month(ex1.timestamp);
myear = year(ex1.timestamp);

myear = unique(myear);      %finding year
mnum = unique(mnum);        %fingind month number
dlast = unique(max(dnum));  %finding last day

    


% finding avg wind speed

[gNum1,gName1] = findgroups(dnum);
avgWS = splitapply(@mean,ex1.CH1Avg,gNum1); %finding average wind speed per day

avg_last= mean(avgWS); %finding average wind speed for month

%%plotting
figure

plot(ex1.timestamp(getrows),ex1.CH1Avg(getrows))
grid
hAx = gca;

xlim([datetime(startdate) datetime(enddate)])
  xtickformat('d')
xticks(datetime(startdate) : caldays(1) : datetime(enddate))

Btw when I run your code, somehow the last day it is not plotted. Look at the screenshot. With my code it is working perfectly. Btw thanks a lot.

Thanks a lot for your fast response @Star Strider

[Star Strider]

Try this:

DL = load('april.mat');
ex1 = DL.ex1;

monthinfo = ex1.timestamp([1 end]);
daylim = day(monthinfo);

figure
plot((1:size(ex1,1)),ex1.CH1Avg)
xt = get(gca,'XTick');
xlim([0, size(ex1,1)])
set(gca,'XTick',linspace(min(xt),size(ex1,1),daylim(2)), 'XTickLabel',compose('%02d',(daylim(1):daylim(2))))

That should plot the x-ticks and x-limits correctly.

[Gligor Terziev]

Thanks a lot.

[Star Strider]

As always, my pleasure!