scale_datetime: Add a date-time scale to a ggvis object.

Description

A date/time scale controls the mapping of date and time variables to visual properties.

Usage

scale_datetime(vis, property, domain = NULL, range = NULL, reverse = NULL,
  round = NULL, utc = NULL, clamp = NULL, nice = NULL, expand = NULL,
  name = property, label = NULL, override = NULL)

Arguments

vis

A ggvis object.

property

The name of a property, such as "x", "y", "fill", "stroke", etc.

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

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 t

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.

utc

if TRUE, uses UTC times. Default is FALSE.

clamp

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

nice

If specified, modifies the scale domain to use a more
human-friendly value range. Should be a string indicating the desired time
interval; legal values are "second", "minute", "hour", "day", "week",
"month", or "year".

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

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 T

`See Also`

scales, scale_numeric,
  https://github.com/trifacta/vega/wiki/Scales#time-scale-properties
Other scales: scale_logical,
  scale_nominal, scale_ordinal;
  scale_numeric

`Examples`

Run this codeset.seed(2934)
dat <- data.frame(
  time = as.Date("2013-07-01") + 1:100,
  value = seq(1, 10, length.out = 100) + rnorm(100)
)
p <- dat %>% ggvis(~time, ~value) %>% layer_points()

# Start and end on month boundaries
p %>% scale_datetime("x", nice = "month")


dist <- data.frame(times = as.POSIXct("2013-07-01", tz = "GMT") +
                           rnorm(200) * 60 * 60 * 24 * 7)
p <- dist %>% ggvis(x = ~times) %>% layer_histograms()
p

# Start and end on month boundaries
p %>% scale_datetime("x", nice = "month")

p %>% scale_datetime("x", utc = TRUE)
Run the code above in your browser using DataLab