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How to plot temporal changes in batches of data?

Asked by David Crowe on 12 Jun 2018
Latest activity Commented on by David Crowe on 13 Jun 2018
Accepted Answer by dpb
Hello! I have a CSV file with the following example content:
SSID,RSS,Unit,Time,Batch
AP1,-40,dBm,11:11:11,0
AP2,-44,dBm,11:11:11,0
AP3,-90,dBm,11:11:11,0
AP1,-50,dBm,13:30:00,1
AP2,-66,dBm,13:30:00,1
AP3,-20,dBm,13:30:00,1
AP1,-2,dBm,15:00:00,2
AP2,-30,dBm,15:00:00,2
AP3,-40,dBm,15:00:00,2
And I'm wanting to plot each of the SSIDs with their RSS (received signal strength) with respect to its batch.
So far, I've tried plotting each of the RSS for each batch and get the following figure:
However, my goal is to connect these lines in a distinct way to show their temporal trend, like so:
Any pointers on how this might be done?

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2 Answers

Answer by dpb
on 13 Jun 2018
Edited by dpb
on 13 Jun 2018
 Accepted Answer

t=readtable('crowe.csv');
t.SSID=categorical(t.SSID);
t.Time=datetime(t.Time);
figure,hold on
[g,ids]=findgroups(t.SSID);
splitapply(@(x,y) plot(x,y,'o-'),t.Time,t.RSS,g);
legend(categories(ids),'location','best')
gives

  1 Comment

This is perfect, dpb! I appreciate using the time data as well. Many thanks for your timely response.

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Answer by Kelly Kearney
on 12 Jun 2018

Assuming your file is read into a table array, I think the quickest way to do this is to unstack the SSID data and then plot:
tbl = readtable('data.csv');
tblu = unstack(tbl, 'RSS', 'SSID');
plot(tblu.Batch, [tblu.AP1 tblu.AP2 tblu.AP3]);
Depending on the number of unique SSIDs, you may prefer to concatenate the unstacked values programmatically, but here I simply typed it manually.

  1 Comment

I had no idea about unstacking, thanks for the help Kelly!

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