[R] how to specify point symbols in the key on a lattice dotplot

[Christopher W. Ryan]

For me, Bert's suggestion produces a plot with two black symbols above
the plotting region, a circle and a triangle, both filled, and no text.

This, in which I specify several features of the symbols in the key,

dd %>%  dotplot( segment ~ transit_time, groups = impact,  data = .,
                pch = 16:17,
                col = 1:2,
                cex = 1.8,
                scales = list(cex = 1.4),
                key = list(text = list(c("impaction", "no impaction")),
points = list(pch =16:17, col = 1:2) ))

gets me what I want.

When using key = (), is it necessary to specify all features of the
plotting symbols and the text? I was under the impression that auto.key
and/or simpleKey (which I'd also tried) had certain defaults, but one or
more of those defaults could be changed by providing arguments, with all
unspecified features remaining at their respective defaults.  

Thanks.

--Chris Ryan




On Fri, 13 Sep 2024 10:45:08 -0700, Bert Gunter wrote:

>"Why does key = list(points = 16:17)  not work? "
>
>Because, from the "key" section of ?xyplot
>" The contents of the key are determined by (possibly repeated)
>components named "rectangles", "lines", "points" or "text". Each of
>these must be **lists** with relevant graphical parameters (see later)
>controlling their appearance."
>
>Ergo, try:
>
>dd |> dotplot( segment ~ transit_time, groups = impact,  data = .,
>                pch = 16:17,
>                cex = 1.8,
>                scales = list(cex = 1.4),
>                key = list(points = list(pch =16:17) ))
>
>Cheers,
>Bert
>
>
>On Fri, Sep 13, 2024 at 9:53 AM Christopher W. Ryan
><cwr using agencystatistical.com> wrote:
>>
>>
>> dd %>% dotplot( segment ~ transit_time, groups = impact,  data = .,
>>                pch = 16:17,
>>                cex = 1.8,
>>                scales = list(cex = 1.4),
>>                key = list(points = 16:17) )
>>
>> produces a graph with no discernible key, but with an asterisk at the
>> top, above the plotting region.
>>
>> Same result from
>>
>> dd %>% dotplot( segment ~ transit_time, groups = impact,  data = .,
>>                pch = 16:17,
>>                cex = 1.8,
>>                scales = list(cex = 1.4),
>>                key = list(points = 16:17),
>>                auto.key = TRUE )
>>
>>
>>
>>
>> dd %>% dotplot( segment ~ transit_time, groups = impact,  data = .,
>>                scales = list(cex = 1.4),
>>                par.settings = simpleTheme(pch = 16:17, cex = 1.8),
>>                auto.key = TRUE)
>>
>> produces the desired result.
>>
>> Why does key = list(points = 16:17)  not work?  Below is a MWE:
>>
>> ================================
>>
>> library(lattice)
>> library(dplyr)
>> dd <- structure(list(impact = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 2L,
>> 2L), levels = c("impaction", "no impaction"), class = "factor"),
>>     segment = structure(c(4L, 2L, 1L, 3L, 4L, 2L, 1L, 3L), levels =
>> c("left", "right", "rectosigmoid", "total"), class = c("ordered",
>> "factor" )), transit_time = c(70, 10, 20, 32, 42, 10, 12, 18)),
>> class = "data.frame", row.names = c(NA, -8L))
>>
>> dd %>% dotplot( segment ~ transit_time, groups = impact,  data = .,
>>                pch = 16:17,
>>                cex = 1.8,
>>                scales = list(cex = 1.4),
>>                key = list(points = 16:17) )
>>
>> =================================
>>
>>
>> Thanks.
>>
>> --Chris Ryan
>> --
>> Agency Statistical Consulting, LLC
>> Helping those in public service get the most from their data.
>> www.agencystatistical.com
>>
>> Public GnuPG email encryption key at
>> https://keys.openpgp.org
>> 9E53101D261BEC070CFF1A0DC8BC50E715A672A0
>>
>>
>> On Fri, 13 Sep 2024 08:29:20 +0100, CALUM POLWART wrote:
>>  
>> >Add:
>> >
>> >key = list(points=16:17)
>> >
>> >Into the dotplot section possibly without the autokey
>> >
>> >On Fri, 13 Sep 2024, 08:19 Christopher W. Ryan,
>> ><cwr using agencystatistical.com> wrote:
>> >  
>> >> I am making a dotplot with lattice, as follows:
>> >>
>> >> dd %>% dotplot( segment ~ transit_time, groups = impact,  data =
>> >> ., as.table = TRUE,
>> >>                 pch = 16:17,
>> >>                 cex = 1.8,
>> >>                 scales = list(cex = 1.4),
>> >>                auto.key = TRUE)
>> >>
>> >> impact is a factor with two levels.
>> >>
>> >> They key shows 2 open circles, one of each color of my two
>> >> plotting symbols, one for each group. I would like the
>> >> symbols in the key to match the plotting characters in the graph:
>> >> 16 (filled circle) for one group and 17 (filled triangle) for the
>> >> second group.  How would I do that? I have not had any success
>> >> with supplying arguments to auto.key, simpleKey, or key. Guess
>> >> I'm not understanding the syntax.
>> >>
>> >> Thanks.
>> >>
>> >> --Chris Ryan
>> >>
>> >> --
>> >> Agency Statistical Consulting, LLC
>> >> Helping those in public service get the most from their data.
>> >> www.agencystatistical.com
>> >>
>> >> Public GnuPG email encryption key at
>> >> https://keys.openpgp.org
>> >> 9E53101D261BEC070CFF1A0DC8BC50E715A672A0
>> >>
>> >> ______________________________________________
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>> >>  
>>
>> ______________________________________________
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>> https://www.R-project.org/posting-guide.html and provide commented,
>> minimal, self-contained, reproducible code.