# Re: [R] Help needed with lattice graph!

From: Paul Murrell <p.murrell_at_auckland.ac.nz>
Date: Sat 23 Apr 2005 - 06:39:17 EST

Hi

```>>Dear R users,
>>
>>If I manage to sort out this graph, it is certainly a candidate for the
>>new R graph gallery
>>
>>I created the following lattice graph:
>>
>>library(lattice)
>>tmp <- expand.grid(geology = c("Sand","Clay","Silt","Rock"),
>>   species =
>>c("ArisDiff","BracSera","CynDact","ElioMuti","EragCurS","EragPseu"),
>>   dist = seq(1,9,1) )
>>tmp\$height <- rnorm(216)
>>sps <- trellis.par.get("superpose.symbol")
>>sps\$pch <- 1:6
>>trellis.par.set("superpose.symbol", sps)
>>   xyplot( height ~ dist | geology, data = tmp,
>>     groups = species, type = "b", cex = 1.2,
>>     layout = c(2,2),
>>     lines = list(col="grey"),
>>     key = list(columns = 2, type = "b", cex = 1.2,
>>       text = list(paste(unique(tmp\$species))),
>>       points = Rows(sps, 1:6)
>>       )
>>   )
```

>
>
> I would do something like this instead:
>
> ---------------------------
>
> library(lattice)
> lattice.options(default.theme = canonical.theme(color = FALSE))
>
>
> tmp <-
> expand.grid(geology = c("Sand","Clay","Silt","Rock"),
> species = c("ArisDiff", "BracSera", "CynDact",
> "ElioMuti", "EragCurS", "EragPseu"),
> dist = seq(1,9,1) )
>
> tmp\$height <- rnorm(216)
>
>
> sp <- list(superpose.symbol = list(pch = 1:6, cex = 1.2),
> superpose.line = list(col = "grey", lty = 1))
>
> xyplot(height ~ dist | geology, data = tmp,
> groups = species,
> type = "b",
> layout = c(2,2),
> par.settings = sp,
> auto.key = list(columns = 2, lines = TRUE))
>
> -------------------------
>
>
```>>However, for once, the R defaults are not to my liking. I plot the graph
>>to postscript and the result is less then optimal.
>>
>>I would like to plot the point symbols in black and white, both in the
>>graphs and the key. I would like the lines to be a single style (grey or
>>a light dash) and preferably the lines do not go through the symbols
>>(like figure 4.11 in the MASS book).
```

>
>
>
> type='b' is the right choice, and it works in standard graphics, but not in
> lattice (where it's same as type='o'). If you really want it, bug Paul to add
> support for it in grid.

[Paul exhibits bug-avoidance behaviour by suggesting a low-level workaround ...]

xyplot(height ~ dist | geology, data = tmp,

```        groups = species,
layout = c(2,2),
panel = function(x, y, type, ...) {
panel.superpose(x, y, type="l", ...)
lpoints(x, y, pch=16, col="white", cex=2)
panel.superpose(x, y, type="p"...)
},
par.settings = sp,
auto.key = list(columns = 2, lines = TRUE))

```

> To get the points and lines combined in the key, you could do
>
> xyplot(height ~ dist | geology, data = tmp,
> groups = species,
> type = "b",
> layout = c(2,2),
> par.settings = sp,
> key =
> list(columns = 2,
> lines = list(col="grey", type = "b", cex = 1.2, pch = 1:6),
> text = list(levels(tmp\$species))))
>
> but evidently there's no way to separately control the color of the line and
> the points on it.
>
> Deepayan
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help

```--
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
paul@stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/

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