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Calculate psychrometric properties of moist air

Source: R/stat.R
stat.Rd

Calculate psychrometric properties of moist air

Usage

stat_relhum(
  mapping = NULL,
  data = NULL,
  geom = "point",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

stat_wetbulb(
  mapping = NULL,
  data = NULL,
  geom = "point",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

stat_vappres(
  mapping = NULL,
  data = NULL,
  geom = "point",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

stat_specvol(
  mapping = NULL,
  data = NULL,
  geom = "point",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

stat_enthalpy(
  mapping = NULL,
  data = NULL,
  geom = "point",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings created by aes(). If specified and inherit.aes = TRUE (the default), it is combined with the default mapping at the top level of the plot. You must supply mapping if there is no plot mapping.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

geom

The geometric object to use to display the data for this layer. When using a stat_*() function to construct a layer, the geom argument can be used to override the default coupling between stats and geoms. The geom argument accepts the following:

  • A Geom ggproto subclass, for example GeomPoint.

  • A string naming the geom. To give the geom as a string, strip the function name of the geom_ prefix. For example, to use geom_point(), give the geom as "point".

  • For more information and other ways to specify the geom, see the layer geom documentation.

position

A position adjustment to use on the data for this layer. This can be used in various ways, including to prevent overplotting and improving the display. The position argument accepts the following:

  • The result of calling a position function, such as position_jitter(). This method allows for passing extra arguments to the position.

  • A string naming the position adjustment. To give the position as a string, strip the function name of the position_ prefix. For example, to use position_jitter(), give the position as "jitter".

  • For more information and other ways to specify the position, see the layer position documentation.

...

Other arguments passed on to layer()'s params argument. These arguments broadly fall into one of 4 categories below. Notably, further arguments to the position argument, or aesthetics that are required can not be passed through .... Unknown arguments that are not part of the 4 categories below are ignored.

  • Static aesthetics that are not mapped to a scale, but are at a fixed value and apply to the layer as a whole. For example, colour = "red" or linewidth = 3. The geom's documentation has an Aesthetics section that lists the available options. The 'required' aesthetics cannot be passed on to the params. Please note that while passing unmapped aesthetics as vectors is technically possible, the order and required length is not guaranteed to be parallel to the input data.

  • When constructing a layer using a stat_*() function, the ... argument can be used to pass on parameters to the geom part of the layer. An example of this is stat_density(geom = "area", outline.type = "both"). The geom's documentation lists which parameters it can accept.

  • Inversely, when constructing a layer using a geom_*() function, the ... argument can be used to pass on parameters to the stat part of the layer. An example of this is geom_area(stat = "density", adjust = 0.5). The stat's documentation lists which parameters it can accept.

  • The key_glyph argument of layer() may also be passed on through .... This can be one of the functions described as key glyphs, to change the display of the layer in the legend.

na.rm

If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes. It can also be a named logical vector to finely select the aesthetics to display. To include legend keys for all levels, even when no data exists, use TRUE. If NA, all levels are shown in legend, but unobserved levels are omitted.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. annotation_borders().

Details

  • stat_relhum requires an extra relhum aesthetics for relative humidity in range [0, 100] in %

  • stat_wetbulb requires an extra wetbulb aesthetics for wet-bulb temperature in degree_F [IP] or degree_C [SI]

  • stat_vappres requires an extra vappres aesthetics for partial pressure of water vapor in moist air in Psi [IP] or Pa [SI]

  • stat_specvol requires an extra specvol aesthetics for specific volume of moist air in ft3 lb-1 of dry air [IP] or in m3 kg-1 of dry air [SI]

  • stat_enthalpy requires an extra enthalpy aesthetics for moist air enthalpy in Btu lb-1 [IP] or J kg-1

What these ggplot2::ggproto() objects do are to take input values, calculate the corresponding humidity ratio and replace the y aesthetic values in each group.

All of stats above requires two additional aesthetics:

  • units: A single string indicating the unit system to use. Should be either "SI" or "IP", or waiver() which uses the value from the parent plot. Default: waiver()

  • pres: A single number indicating the atmosphere pressure in Pa [SI] or Psi [IP]. If waiver(), the pressure calculated from the parent plot's altitude value will be used. Default: waiver()

However, when these stats are used inside a ggplot geom_* as the stat argument, both units and pres have to be specified.

Examples

states <- data.frame(
    tdb = c(18, 22, 26, 30),
    relhum = c(70, 55, 45, 35)
)

ggpsychro(tdb_lim = c(10, 35), hum_lim = c(0, 25)) +
    stat_relhum(aes(x = tdb, relhum = relhum), data = states)


# The stats can also be used from ordinary ggplot2 geoms.
wetbulb_line <- data.frame(tdb = 18:30, wetbulb = 16)
ggpsychro(tdb_lim = c(10, 35), hum_lim = c(0, 25)) +
    geom_grid_wetbulb() +
    geom_line(aes(x = tdb, wetbulb = wetbulb),
        data = wetbulb_line, stat = "wetbulb")


vapour_pressure <- data.frame(
    tdb = c(12, 18, 24, 30),
    vappres = c(900, 1200, 1800, 2400)
)
ggpsychro(tdb_lim = c(10, 35), hum_lim = c(0, 25)) +
    stat_vappres(aes(x = tdb, vappres = vappres),
        data = vapour_pressure)


specific_volume <- data.frame(
    tdb = c(20, 25, 30),
    specvol = c(0.84, 0.86, 0.88)
)
ggpsychro(tdb_lim = c(10, 35), hum_lim = c(0, 25)) +
    stat_specvol(aes(x = tdb, specvol = specvol),
        data = specific_volume)


enthalpy <- data.frame(
    tdb = c(18, 24, 30),
    enthalpy = c(35000, 50000, 65000)
)
ggpsychro(tdb_lim = c(10, 35), hum_lim = c(0, 25)) +
    stat_enthalpy(aes(x = tdb, enthalpy = enthalpy), data = enthalpy)