Understanding Linear-Log Plots & Their Uses

[jimmy1]

What is meant by a linear-log plot and why is it used?

In the book I have, the author is demonstrating that some data fits an exponential distribution. So what he does is a linear-log plot of both the exponential distribution and the empirical data, and then overlaps the 2 graphs so show they follow a similar path.

So my question is, what exactly is a linear-log plot, and when/why do you use it?
For exmaple, if I was to show the data fitted an exponential distribution, I would just plot the data and exponetial distribution as they were, and overlap them and show they fit (or don't fit).

 

[HallsofIvy]

If you have data that happens to lie close to a curve of the form y= A log(x)+ B, (conversely, $x= e^{\frac{y-B}{A}$) then Plotting y against "X= log(x)" rather than x itself puts the points close to the straight line y= AX+ B. Yes, you could overlap your raw data and an exponential (if you were sure of the constants involved) and show that they matched but it is typically much easier to spot a straight line than more complex curves and there are standard formulae for the "best fit" line.