R: Scale key handling for openair

drawOpenKey {openair} | R Documentation

## Scale key handling for openair

### Description

General function for producing scale keys for other openair functions. The function is a crude modification of the draw.colorkey function developed by Deepayan Sarkar as part of the lattice package, and allows additional key labelling to added, and provides some additional control of the appearance and scaling.

### Usage

    drawOpenKey(key, draw = FALSE, vp = NULL)

### Arguments

`key` | List defining the scale key structure to be produced. Most options are identical to original `draw.colorkey` function. Original `draw.colorkey` options: `space` location of the scale key ("left", "right", "top" or "bottom"). Defaults to "right". `col` vector of colours, used in scale key. `at` numeric vector specifying where the colors change. Must be of length 1 more than the col vector. `labels` a character vector for labelling the at values, or more commonly, a list describing characteristics of the labels. This list may include components `labels`, `at`, `cex`, `col`, `rot`, `font`, `fontface` and `fontfamily`. `tick.number` approximate number of ticks. `width` width of the key. `height` height of key. Note: `width` and `height` refer to the key dimensions. `height` is the length of the key along the plot axis it is positioned against, and `width` is the length perpendicular to that. Additional options include: `header` a character vector of extra text to be added above the key, or a list describing some characteristics of the `header`. This list may include components `header`, the character vector of header labels, `tweaks`, a list of local controls, e.g. 'gap' and 'balance' for spacing relative to scale and footer, respectively, `auto.text`, `TRUE/FALSE` option to apply `quickText`, and `slot`, a numeric vector setting the size of the text boxes `header` text is placed in. `footer` as in `header` but for labels below the scale key. Notes: `header` and `footer` formatting can not be set locally, but instead are matched to those set in `labels`. `drawOpenKey` allows for up to six additional labels (three above and three below scale key). Any additional text is ignored. `tweak, auto.text, slot` as in `header` and `footer` but sets all options uniformly. This also overwrites anything in `header` and/or `footer`. `fit` the fit method to be applied to the header, scale key and footer when placing the scale key left or right of the plot. Options include: 'all', 'soft' and 'scale'. The default 'all' fits header, key and footer into `height` range. The alternative 'scale' fits only the key within `height`. (This means that keys keep the same proportions relative to the main plot regardless of positioning but that header and footer may exceed plot dimensions if `height` and/or `slots` are too large. `plot.style` a character vector of key plotting style instructions: Options currently include: 'paddle', 'ticks' and 'border'. 'paddle' applies the incremental paddle layout used by `winRose`. 'ticks' places ticks between the labels scale key. 'border' places a border about the scale key. Any combination of these may be used but if none set, scale key defaults to `c("ticks", "border")` for most plotting operations or `c("paddle")` for `windRose`.
`draw` | Option to return the key object or plot it directly. The default, FALSE, should always be used within openair calls.
`vp` | View port to be used when plotting key. The default, NULL, should always be used within openair calls. (Note: `drawOpenKey` is a crude modification of `lattice::draw.colorkey`, that provides labelling options for `openair` plot scale keys. Some aspects of the function are in development and may to subject to change. Therefore, it is recommended that you use parent `openair` function controls, e.g. `key.position`, `key.header`, `key.footer` options, where possible. `drawOpenKey` may obviously be used in other plots but it is recommended that `draw.colorkey` itself be used wherever this type of additional scale labelling is not required.)

### Details

The `drawOpenKey` function produces scale keys for other openair functions.

Most `drawOpenKey` options are identical to those of `lattice::draw.colorkey`. For example, scale key size and position are controlled via `height`, `width` and `space`. Likewise, the axis labelling can be set in and formatted by `labels`. See `draw.colorkey` for further details.

Additional scale labelling may be added above and below the scale using `header` and `footer` options within `key`. As in other `openair` functions, automatic text formatting can be enabled via `auto.key`.

(Note: Currently, the formatting of `header` and `footer` text are fixed to the same style as `labels` (the scale axis) and cannot be defined locally.)

The relationship between `header`, `footer` and the scale key itself can be controlled using `fit` options. These can be set in `key$fit` to apply uniform control or individually in `key$header$fit` and/or `key$footer$fit` to control locally.

The appearance of the scale can be controlled using `plot.style`.

### Value

The function is a modification of `lattice::draw.colorkey` and returns a scale key using a similar mechanism to that used in in the original function as developed by Deepayan Sarkar.

### Note

We gratefully acknoweldge the considerable help and advice of Deepayan Sarkar.

### Author(s)

`draw.colorkey` is part of the `lattice` package, developed by Deepayan Sarkar.

Additional modifications by Karl Ropkins.

### References

Deepayan Sarkar (2010). lattice: Lattice Graphics. R package version 0.18-5. http://r-forge.r-project.org/projects/lattice/

### See Also

Functions using `drawOpenKey` currently include `windRose`, `pollutionRose`.

For details of the original function, see `draw.colorkey`

### Examples

    ##########
    #example 1
    ##########

    #paddle style scale key used by windRose

    windRose(mydata,)

    #adding text and changing style and position via key

    #note:
    #some simple key control also possible directly
    #For example, below does same as
    #windRose(mydata, key.position="right")

    windRose(mydata,
       key =list(space="right")
    )

    #however:
    #more detailed control possible working with
    #key and drawOpenKey. For example,

    windRose(mydata,
       key = list(header="Title", footer="wind speed",
                  plot.style = c("ticks", "border"),
                  fit = "all", height = 1,
                  space = "top")
    )

[Package openair version 2.8-5 Index]