MATLAB Answers


No Lines between points when plotting on ThingSpeak (Example ThingSpeak Code)

Asked by Ragnar Schäning on 31 Mar 2019
Latest activity Commented on by Ragnar Schäning on 3 Apr 2019
I am having problems with a simple 2-y-axis plot on ThingSpeak.
The measurement dots just do not get connected by a line.
Does anyone have an idea why that happens?
This is my code: (even the example ThingSpeak code)
readChannelID = [685541];
fieldID1 = [1];
fieldID2 = [2];
readAPIKey = '*************';
[data1, time1] = thingSpeakRead(readChannelID, 'Field', fieldID1, 'NumPoints', 3600, 'ReadKey', readAPIKey);
[data2, time2] = thingSpeakRead(readChannelID, 'Field', fieldID2, 'NumPoints', 3600, 'ReadKey', readAPIKey);
yyaxis left;
plot(time1, data1,'-x')
ylim([15 37])
yyaxis right;
plot(time2, data2,'-x');
ylim([0 100])


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1 Answer

Answer by Vinod
on 1 Apr 2019
 Accepted Answer

It is very likely that your data has NaN's in them. You can remove the missing entries using the RMMISSING function before plotting. Your code might look like this:
data1 = thingSpeakRead(readChannelID, 'NumPoints', 3600, 'ReadKey', readAPIKey,'OutputFormat','timetable');
cleanData1 = rmmissing(data1);
plot(cleanData1.Timestamps, cleanData1.Field1);

  1 Comment

Thank you very much, it actually worked.
Have a great day!

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