# symbolmap

##### Graphics Symbol Map

Create a graphics symbol map that associates data values with graphical symbols.

##### Usage

`symbolmap(..., range = NULL, inputs = NULL)`

##### Arguments

- ...
- Named arguments specifying the graphical parameters. See Details.
- range
- Optional. Range of numbers that are mapped.
A numeric vector of length 2 giving the minimum and maximum
values that will be mapped.
Incompatible with
`inputs`

. - inputs
- Optional. A vector containing all the data values
that will be mapped to symbols.
Incompatible with
`range`

.

##### Details

A graphical symbol map is an association between
data values and graphical symbols.
The command `symbolmap`

creates an object of class
`"symbolmap"`

that represents a graphical symbol map.

Once a symbol map has been created, it can be applied to any
suitable data to generate a plot of those data.
This makes it easy to ensure that
the *same* symbol map is used in two different plots.
The symbol map can be plotted as a legend to the plots,
and can also be plotted in its own right.
The possible values of data that will be mapped
are specified by `range`

or `inputs`

.

- if
`range`

is given, it should be a numeric vector of length 2 giving the minimum and maximum values of the range of numbers that will be mapped. These limits must be finite. - if
`inputs`

is given, it should be a vector of any atomic type (e.g. numeric, character, logical, factor). This vector contains all the possible data values that will be mapped. - If neither
`range`

nor`inputs`

is given, it is assumed that the possible values are real numbers.

`...`

which are given in `name=value`

form.
These arguments specify the kinds of symbols that will be
used, the sizes of the symbols, and graphics parameters for
drawing the symbols. Each graphics parameter can be either a single
value, for example `shape="circles"`

,
or a `function(x)`

which determines the value
of the graphics parameter as a function of the data `x`

,
for example `shape=function(x) ifelse(x > 0, "circles", "squares")`

.
Colourmaps (see `colourmap`

) are also acceptable
because they are functions.
Currently recognised graphics parameters, and their
allowed values, are:
[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

##### Value

- An object of class
`"symbolmap"`

.

##### See Also

`plot.symbolmap`

to plot the symbol map itself.
`invoke.symbolmap`

to apply the symbol map to some data
and plot the resulting symbols.
`update.symbolmap`

to change the symbol map.

##### Examples

```
g <- symbolmap(inputs=letters[1:10], pch=11:20)
g1 <- symbolmap(range=c(0,100), size=function(x) x/50)
g2 <- symbolmap(shape=function(x) ifelse(x > 0, "circles", "squares"),
size=function(x) sqrt(ifelse(x > 0, x/pi, -x)),
bg = function(x) ifelse(abs(x) < 1, "red", "black"))
colmap <- colourmap(terrain.colors(20), range=c(0,10))
g3 <- symbolmap(pch=21, fg=colmap, range=c(0,10))
```

*Documentation reproduced from package spatstat, version 1.42-2, License: GPL (>= 2)*