I am a complete mathematical ignoramus, so forgive me if the answer to my question is something boringly obvious, as I can only imagine it is. I am trying to figure what in the world the actual numbers are for the population density in this figure (section B):
fig. 4 of "https://www.pnas.org/content/115/6/1232/tab-figures-data"
now it seems to me that the population density is given in terms of the natural logarithm(log e# per 100km2) of the number on the scale, I assume because there is a wide range of numbers to work with. So the upper end of population density is ln(5)/100km2, right? But my extremely limited understanding of natural logarithms tells me that that number has to be lower than 5, which is impossibly low, and furthermore the negative values on the lower end would just be invalid. I downloaded the supplmentary data for this article to try and get an answer, but all I could deduce was that their standard for "outlier" population densities was 2 data sets >300/100km2, so obviously the upper end of population density here cant be a paltry ln(5).
I am assuming there is some blatantly obvious graphing convention or something I just don't know about, or my 15 minutes looking up what the heck "log e" means has sent me down a very incorrect line of logic. Either way, I could really use some help in interpreting this data.