# how to set y-axis as log scale?

4,177 views (last 30 days)
Rohit Bhoi on 15 Apr 2016
Commented: Adam Danz on 12 Jul 2024 at 15:08
I am plotting x-y plot using plot function. I want to set only y-axis as log scale and x-axis as linear? How to do that? I used loglog function but it scales both axis but I want only Y.

Walter Roberson on 22 Sep 2023
Edited: MathWorks Support Team on 22 Sep 2023
The best way to create that type of axes is to use the semilogy function. Alternatively, you can set the ‘YScale’ property on the axes:
set(gca, 'YScale', 'log')
***Update from Mathworks Support Team - September 2023***
As of R2023b, you can also use the 'yscale ' function.
Mr Thadi on 4 Jul 2024
Thank you Mr walter,
i have attached one image,
in that my data file having values from 100 to 14000.
if i plot histogram without x axis set properties it showing like figure 'A', in that bins starts from 0-300,300-600...etc like that.
but if i use set (gca,'xscale','log') command to the x scale it showing initial bin from 300-600,600-900....etc.you can see in figure 'B'
my question is what about values in between 0-300 from figure 'B' , why these are not appearing how to solve it,if i want to get xscale in log values histogram initial bin from 0-300,300-600...etc are needed to change properties in that to command?can you please explain me
i can provide my data file also to you
Adam Danz on 12 Jul 2024 at 15:08
This issue arises because the first bin edge is at x=0 and log(0)=-inf which cannot be represented graphically.
Assuming there are no data less than or equal to 0 and no bin edges less than 0, you could set the first bin edge according to the smallest value in the data.
x = rand(1,1000)*10000;
minPositiveValue = min(x(x>0),[],'all');
minbin = 10^floor(log10(minPositiveValue));
ax = axes();
h = histogram(ax, x);
ax.XScale = 'log';
if h.BinEdges(1) == 0
h.BinEdges(1) = minbin;
end

Toshia M on 20 Sep 2023
Starting in R2023b, you can change the scale of any axis after you create the plot by calling the xscale, yscale, or zscale function.
For example, create a plot of two vectors x and y. Then set the scale of the y-axis to logarithmic.
x = 1:100;
y = x.^2;
plot(x,y)
grid on
yscale log

Rohit Sinha on 27 Apr 2022
The easiest way to do this is simply use the following command instead of plot
semilogy(x,y);
This will plot x axis on a linear scale and y axis on a log scale. Similarly, if you want to plot x axis on log scale and y axis on a linear scale, you can use
semilogx(x,y) ;
Walter Roberson on 27 Apr 2022
semilogy() is the first thing I mentioned in my answer in 2016.
Nicholas Santiago on 4 Nov 2022
yo i totally missed that I generally only read the bold stuff, thanks a ton!

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