[R] Axis with inverse logarithmic scale

[Martin Maechler]

>>>>> Martin Maechler 
>>>>>     on Tue, 28 Jul 2020 15:56:10 +0200 writes:

>>>>> John Fox 
>>>>>     on Mon, 27 Jul 2020 12:57:57 -0400 writes:

    >> Dear Dileepkumar R,
    >> As is obvious from the tick marks, the vertical axis is not log-scaled:

    >>> log10(99.999) - log10(99.99)
    >> [1] 3.908865e-05
    >>> log10(99) - log10(90)
    >> [1] 0.04139269


    >> That is, these (approximately?) equally spaced ticks aren't equally 
    >> spaced on the log scale.

    >> The axis is instead apparently (at least approximately) on the logit 
    >> (log-odds) scale:

    >>> library(car)
    >> Loading required package: carData
    >>> logit(99.999) - logit(99.99)
    >> [1] 2.302675
    >>> logit(99) - logit(90)
    >> [1] 2.397895

    > Small remark : You don't need car (or any other extra pkg) to have logit:

    > logit <- plogis # is sufficient

    > Note that the ?plogis (i.e. 'Logistic') help page has had a
    > \concept{logit}

    > entry (which would help if one used  help.search() .. {I don't;
    > I have 10000 of packages}),
    > and that same help page has been talking about 'logit' for ca 16
    > years now (and I'm sure this is news for most readers, still)...

but now I see that car uses the "empirical logit" function,
where plogis() provides the mathematical logit():

The former is typically needed for data transformations where
you don't want to map {0,1} to  -/+ Inf but rather to finite
values ..

So I should stayed quiet, probably..

Martin


    >> You can get a graph close to the one you shared via the following:

    >> library(car) # repeated so you don't omit it

    > .. and here you need 'car'  for the nice  probabilityAxis(.) ..

    >>> logits <- logit(y_values)
    >>> plot(x_value, logits, log="x", axes=FALSE,
    >> +      xlim=c(1, 200), ylim=logit(c(10, 99.999)),
    >> +      xlab="Precipitation Intensity (mm/d)",
    >> +      ylab="Cumulative Probability",
    >> +      main="Daily U.S. Precipitation",
    >> +      col="magenta")
    >>> axis(1, at=c(1, 2, 5, 10, 20, 50, 100, 200))
    >>> probabilityAxis(side=2, at=c(10, 30, 50, 90, 99, 99.9, 99.99, 
    >> 99.999)/100)
    >>> box()

    >> Comments:

    >> This produces probabilities, not percents, on the vertical axis, which 
    >> conforms to what the axis label says. Also, the ticks in the R version 
    >> point out rather than into the plotting region -- the former is 
    >> generally considered better practice. Finally, the graph is not a 
    >> histogram as the original title states.

    >> I hope this helps,
    >> John


    >> --------------------------------------------
    >> John Fox
    >> Professor Emeritus
    >> McMaster University
    >> Hamilton, Ontario, Canada
    >> web: https://socialsciences.mcmaster.ca/jfox/

    >> On 7/27/2020 11:56 AM, Dileepkumar R wrote:
    >>> I think the attached sample figure is not visible
    >>> Here is the sample figure:
    >>> https://drive.google.com/file/d/16Uy3JD0wsEucUv_KOhXCxLZ4U-3wiBTs/view?usp=sharing
    >>> 
    >>> sincerely,
    >>> 
    >>> 
    >>> Dileepkumar R
    >>> 
    >>> 
    >>> 
    >>> 
    >>> On Mon, Jul 27, 2020 at 7:13 PM Dileepkumar R <dileepkunjaai using gmail.com>
    >>> wrote:
    >>> 
    >>>> Dear All,
    >>>> 
    >>>> I want to plot a simple cumulative probability distribution graph with
    >>>> like the attached screenshot.
    >>>> But I couldn't fix the y-axis scale as in that screenshot.
    >>>> 
    >>>> My data details are follows:
    >>>> 
    >>>> y_values
    >>>> =c(66.78149,76.10846,81.65518,85.06448,87.61703,89.61314,91.20297,92.36884,
    >>>> 93.64070,94.57693,95.23052,95.75163,96.15792,96.58188,96.97933,97.29730,
    >>>> 97.59760,97.91556,98.14520,98.37485,98.57799,98.74580,98.87829,99.06377,
    >>>> 99.16093,99.25808,99.37290,99.45239,99.54072,99.59371,99.62904,99.66437,
    >>>> 99.69970,99.70853,99.72620,99.73503,99.77036,99.79686,99.80569,99.82335,
    >>>> 99.83219,99.84985,99.86751,99.87635,99.87635,99.90284,99.90284,99.90284,
    >>>> 99.91168,99.92051,99.92051,99.93817,99.93817,99.93817,99.95584,99.95584,
    >>>> 99.97350,99.97350,99.97350,99.97350,99.97350,99.97350,99.97350)
    >>>> 
    >>>> x_value=seq(63)
    >>>> 
    >>>> Thank you all in advance
    >>>> 
    >>>> Dileepkumar R
    >>>> 
    >>> 
    >>> [[alternative HTML version deleted]]
    >>> 
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    >>> 

    >> ______________________________________________
    >> 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.

    > ______________________________________________
    > 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.