ggvis (version 0.4.9)

scale_numeric: Add a numeric scale to a ggvis object.

Description

A numeric (quantitative) scale controls the mapping of continuous variables to visual properties.

Usage

scale_numeric(
  vis,
  property,
  domain = NULL,
  range = NULL,
  reverse = NULL,
  round = NULL,
  trans = NULL,
  clamp = NULL,
  exponent = NULL,
  nice = NULL,
  zero = NULL,
  expand = NULL,
  name = property,
  label = NULL,
  override = NULL
)

Arguments

vis

A ggvis object.

property

The name of a visual property, such as "x", "y", "fill", "stroke". Note both x and x2 use the "x" scale (similarly for y and y2). fillOpacity, opacity and strokeOpacity use the "opacity" scale.

domain

The domain of the scale, representing the set of data values. For ordinal scales, a character vector; for quantitative scales, a numeric vector of length two. Either value (but not both) may be NA, in which case domainMin or domainMax is set. For dynamic scales, this can also be a reactive which returns the appropriate type of vector.

range

The range of the scale, representing the set of visual values. For numeric values, the range can take the form of a two-element array with minimum and maximum values. For ordinal data, the range may by an array of desired output values, which are mapped to elements in the specified domain. The following range literals are also available: "width", "height", "shapes", "category10", "category20".

reverse

If true, flips the scale range.

round

If true, rounds numeric output values to integers. This can be helpful for snapping to the pixel grid.

trans

A scale transformation: one of "linear", "log", "pow", "sqrt", "quantile", "quantize", "threshold". Default is "linear".

clamp

If TRUE, values that exceed the data domain are clamped to either the minimum or maximum range value. Default is FALSE.

exponent

Sets the exponent of the scale transformation. For pow transform only.

nice

If TRUE, modifies the scale domain to use a more human-friendly number range (e.g., 7 instead of 6.96). Default is FALSE.

zero

If TRUE, ensures that a zero baseline value is included in the scale domain. This option is ignored for non-quantitative scales. Default is FALSE.

expand

A multiplier for how much the scale should be expanded beyond the domain of the data. For example, if the data goes from 10 to 110, and expand is 0.05, then the resulting domain of the scale is 5 to 115. Set to 0 and use nice=FALSE if you want exact control over the domain. If left NULL, behavior will depend on the scale type. For positional scales (x and y), expand will default to 0.05. For other scales, it will default to 0.

name

Name of the scale, such as "x", "y", "fill", etc. Can also be an arbitrary name like "foo".

label

Label for the scale. Used for axis or legend titles.

override

Should the domain specified by this ggvis_scale object override other ggvis_scale objects for the same scale? Useful when domain is manually specified. For example, by default, the domain of the scale will contain the range of the data, but when this is TRUE, the specified domain will override, and the domain can be smaller than the range of the data. If FALSE, the domain will not behave this way. If left NULL, then it will be treated as TRUE whenever domain is non-NULL.

Details

The default values for most of the arguments is NULL. When the plot is created, these NULL values will be replaced with default values, as indicated below.

See Also

scales, scale_ordinal, https://vega.github.io/vega/docs/scales/#quantitative

Other scales: scale_datetime(), scale_ordinal()

Examples

p <- mtcars %>% ggvis(~wt, ~mpg, fill = ~hp) %>% layer_points()

p %>% scale_numeric("y")

p %>% scale_numeric("y", trans = "pow", exponent = 0.5)

p %>% scale_numeric("y", trans = "log")

# Can control other properties other than x and y
p %>% scale_numeric("fill", domain = c(0, 120), clamp = TRUE)

# Set range of data from 0 to 3
p %>% scale_numeric("x", domain = c(0, 3), clamp = TRUE, expand = 0,
                     nice = FALSE)

# Lower bound is set to lower limit of data, upper bound set to 3.
p %>% scale_numeric("x", domain = c(NA, 3), clamp = TRUE, nice = FALSE)