Log scaling problem | MATLAB IoT Analytics | Forum

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Log scaling problem
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September 8, 2016
7:27 pm
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Forum Posts: 4
Member Since:
September 8, 2016
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I'm trying to plot data on a log scale using this code fragment:

thingSpeakPlot(time, light, 'YScale','log');

however all I get is an empty chart.  The X-axis has time values, but no Y-axis value or data plotted.  The data is read in correctly - I can see it when I plot it without the log.  Can anyone shed some light on this.

September 8, 2016
11:52 pm

Forum Posts: 113
Member Since:
October 12, 2015
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HI vwgtimk5,

It works without any issues in my case ... I hope this help you Smile

copy - paste this code (blindly, no questions, no typing) in a MATLAB Visualizations in MATLAB Code

time = 0:1:5
light = exp(time)
% thingSpeakPlot(time, light);
% thingSpeakPlot(time, light, 'YScale','log');

2 tries,

first try, erase % in first thingSpeakPlot and Save and Run.  See in "output" the values for time and light and the MATLAB Plot Output

second try, put again % in the first thingSpeakPlot and erase % in second thingSpeakPlot and Save and Run. See results.

Maybe the characters in your machine are different.(?)

Good luck

September 10, 2016
12:40 pm
New Member
Forum Posts: 4
Member Since:
September 8, 2016
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It turns out that I had zeros in my data.  The log plot works fine once I adjusted the offending 0 values.

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