[R] plot shows exponential values incompatible with data

[Fox, John]

Dear Luigi,

> On Jul 9, 2020, at 9:59 AM, Luigi Marongiu <marongiu.luigi using gmail.com> wrote:
> 
> Thank you,
> but why it does not work in linear? With the log scale, I know it
> works but I am not looking for it; is there a way to force a linear
> scale?

The scale *is* linear and the choice of tick marks, which are evenly spaced, is reasonable, given that 10^9 is 2 orders of magnitude smaller than 10^11. That is, on a linear scale with this range, 10^9 isn't much larger than 0.

If you really want a tick at 10^9, then you can just put one there:

plot(Y~X, axes=FALSE, frame=TRUE)
axis(1)
axis(2, at=c(1e9, (1:6)*1e11))

But now the ticks aren't evenly spaced (though they appear to be because, as I mentioned, 10^9 is "close" to 0).

Best,
 John

> Regards
> Luigi
> 
> On Thu, Jul 9, 2020 at 3:44 PM Fox, John <jfox using mcmaster.ca> wrote:
>> 
>> Dear Luigi,
>> 
>>> On Jul 9, 2020, at 8:59 AM, Luigi Marongiu <marongiu.luigi using gmail.com> wrote:
>>> 
>>> Hello,
>>> I have these vectors:
>>> ```
>>> X <- 1:7
>>> Y <- c(1438443863, 3910100650, 10628760108, 28891979048, 78536576706,
>>> 213484643920, 580311678200)
>>> plot(Y~X)
>>> ```
>>> The y-axis starts at 0e0, but the first value is 1.4 billion. Why the
>>> axis does not start at 1e9?
>> 
>> Because you're plotting on a linear, not log, scale, and 0*10^11 = 0.
>> 
>>> round(Y/1e11)
>> [1] 0 0 0 0 1 2 6
>> 
>> Then try plot(log(Y) ~ X).
>> 
>> I hope this helps,
>> John
>> 
>>  -----------------------------
>>  John Fox, Professor Emeritus
>>  McMaster University
>>  Hamilton, Ontario, Canada
>>  Web: http::/socserv.mcmaster.ca/jfox
>>> 
>>> 
>>> 
>>> --
>>> Best regards,
>>> Luigi
>>> 
>>> ______________________________________________
>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>> 
> 
> 
> -- 
> Best regards,
> Luigi
> 
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.