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.
drawOpenKey(key, draw = FALSE, vp = NULL)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.
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.
Option to return the key object or plot it directly. The default, FALSE, should always be used within openair calls.
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.)
draw.colorkey is part of the lattice package,
developed by Deepayan Sarkar.
Additional modifications by Karl Ropkins.
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.
Deepayan Sarkar (2010). lattice: Lattice Graphics. R package version 0.18-5. http://r-forge.r-project.org/projects/lattice/
Functions using drawOpenKey currently include
windRose, pollutionRose.
For details of the original function, see draw.colorkey
##########
#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")
)
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