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How to draw line logarithmic x axis and y axis

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Rizwan Khan
Rizwan Khan on 7 Sep 2020
Commented: Adam Danz on 14 Sep 2020
Hi All,
I have some financial data price and time.
I need to plot it on a chart, however, i want the Y axis to be a log scale and the x axis to be a log scale
so both need to be log scaled.
How can i do this?
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Answers (2)

Mario Malic
Mario Malic on 7 Sep 2020
  3 Comments
Rizwan Khan
Rizwan Khan on 7 Sep 2020
I tried using xtickformat('yyyy-MM');
However, i then get the error that this time format does not support log scale?
The coordinate system or ruler class does not support log axis scale.

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Adam Danz
Adam Danz on 14 Sep 2020
Edited: Adam Danz on 14 Sep 2020
Convert the dates to duration from the starting date but use the numeric form of the durations (ie, not the "duration' class). Then you're just working with regular old numbers that can sustain the log scale.
If you want to see the date for each point, add the dates to the datatips.
Demo:
% Create date-time vector and data
dt = datetime(2020,1,1) + days(0:5:365);
data = exp(1:numel(dt));
% Compute number of days since the start of dt.
ndays = days(dt - dt(1));
% Plot data and show starting date in xlabel
h = loglog(ndays,data, 'o');
xlabel(sprintf('Number of days since %s',datestr(dt(1))))
% Now add the dates to each marker in their datatip.
h.DataTipTemplate.DataTipRows(end+1) = dataTipTextRow('Date',dt);
X is the number of days since the first datetime value.
Date shows the datatime value for each data point.

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