# Can the vertical axis of a plot be configured to have log log scaling?

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Andy Hessler on 1 Nov 2019
Commented: Mil Shastri on 1 Nov 2019
Hello,
I’m trying to find software that can plot oil viscosities that follow something called the Walther Equation.
This plots a straight line when the vertical axis is a double log scale.
This is the standard scaling applied to the ASTM D 341-17 chart for plotting viscosities.
Does this software have the ability to set up a vertical axis with this log log scaling?
Thanks for the help,
Andy

Mil Shastri on 1 Nov 2019
This plot is using semilogy(temp, viscosity) command:
and using the plot(temp, log(log(viscosity)) command:
and if you are curious to learn about some of the visualization and data analysis approaches, this is might be a useful (but 55 minute long) video https://www.mathworks.com/videos/matlab-for-excel-users-81634.html?s_tid=srchtitle
Andy Hessler on 1 Nov 2019
Thank you for taking the time to demonstrate this command. As I feared, the vertical data no longer corelates to the original viscosity value. What you've shown is useful for comparing slopes of lines, but not quite what I need for analyzing a specific fluid's temperature/viscosity performance.
I'll try to look at the video, though. Maybe there are other insights.
Thanks!
Mil Shastri on 1 Nov 2019
My pleasure, all the best!

Valeriy on 1 Nov 2019
LL = log10(viscosity);
semilogy(x,LL);
??

#### 1 Comment

Andy Hessler on 1 Nov 2019
Forgive me for not undertanding the syntax of the your reply. It's not a matter of just plotting any straight line...but plotting the straight line for this equation on scaling that is meaninful for discussion. It's imortant that one can read the graph and see the value in cSt (Centistokes).
I am not a user of Matlab...but trying to determine if this is the right software to use to accomplish this challenge in plotting vicsosity.
Can you elaborate? Or...perhaps demonstrate what you mean with a polot using the sample data from above? (If that's not asking too much)
Thank you kindly.