CODEWITHSUNDEEP
plothistogramoctaveaxisscaletransform
djscuf
djscuf

Reputation: 63

Octave plot breaks when setting axis scale to log

I am trying to plot an histogram with the following script:

for i = 1:100
    edges(i) = i * 10;
end

[n] = histc(x, edges);
bar(edges, n, 'histc');

When I try to set the axis to a log scale using

set(gca, 'xscale', 'log')

I get the following message

warning: opengl_renderer: data values greater than float capacity.  (1) Scale data, or (2) Use gnuplot

The data for the histogram (x vector) is the column mq135 of this csv file: https://github.com/pedroscaff/sensor-platform-data-analysis/blob/master/data/prenzl-tempelh.csv

I couldn't find a way to change the scale of the axis to log, any ideas on what might cause this issue? The message is pretty clear about the values, but it does not make any sense to me and plotting a histogram using plot.ly worked out of the box.

Thanks!

Upvotes: 2

Views: 2456

Answers (1)

Andy
Andy

Reputation: 8091

Are you really sure you want the xscale as log and not the yscale? This uses hist but with yscale set to log

base_url = "https://github.com/pedroscaff/sensor-platform-data-analysis/raw/master/data"
fn = "prenzl-tempelh.csv";
if (! exist (fn, "file"))
  urlwrite (fullfile (base_url, fn), fn);
endif

# skipp headerline, extract only mq135
mq135 = csvread (fn, 1, 0)(:, 2);
hist (mq135, 0:20:1000);
xlabel ("MQ-135 gas sensor raw data?")
set(gca, 'yscale', 'log')
set(gca, "xtick", 0:100:1000)
grid on
print ("out.png");

gives

hist plot, yscale log

Upvotes: 2

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