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Bin data on psychrometric chart coordinates

Source: R/stat-psychro-bin.R
stat_psychro_bin.Rd

stat_psychro_bin() bins observations on dry-bulb temperature and humidity ratio coordinates. geom_psychro_tile() draws the result as tiles, which is useful for weather-hour distributions and gridded simulation summaries.

Usage

stat_psychro_bin(
  mapping = NULL,
  data = NULL,
  geom = "tile",
  position = "identity",
  ...,
  bins = 30,
  binwidth = NULL,
  boundary = c(0, 0),
  drop = TRUE,
  fun = "sum",
  gap = 0.08,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

geom_psychro_tile(
  mapping = NULL,
  data = NULL,
  stat = "psychro_bin",
  position = "identity",
  ...,
  gap = 0.08,
  boundary = c(0, 0),
  cell.grid = TRUE,
  cell.grid.colour = ggplot2::waiver(),
  cell.grid.linewidth = ggplot2::waiver(),
  cell.grid.linetype = ggplot2::waiver(),
  cell.grid.alpha = ggplot2::waiver(),
  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.

bins

Number of bins in the dry-bulb and humidity-ratio directions. A single number is recycled to both directions. Ignored when binwidth is supplied.

binwidth

Width of bins in chart display units. The first value is in dry-bulb temperature units, and the second value is in humidity-ratio units (g/kg for SI and gr/lb for IP). A single number is recycled to both directions.

boundary

Bin boundary in chart display units. The first value is a dry-bulb temperature boundary, and the second value is a humidity-ratio boundary (g/kg for SI and gr/lb for IP). A single number is recycled to both directions. Only used when binwidth is supplied.

drop

If TRUE, the default, omit empty bins.

fun

Summary function used when the value aesthetic is supplied. One of "sum", "mean", "median", "min", or "max".

gap

Relative gap between adjacent tiles. The default, 0.08, draws tiles at 92% of the bin width and height. Use gap = 0 for full-size tiles. Must be a single finite number greater than or equal to 0 and less than 1.

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().

stat

The statistical transformation to use on the data for this layer. When using a geom_*() function to construct a layer, the stat argument can be used to override the default coupling between geoms and stats. The stat argument accepts the following:

  • A Stat ggproto subclass, for example StatCount.

  • A string naming the stat. To give the stat as a string, strip the function name of the stat_ prefix. For example, to use stat_count(), give the stat as "count".

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

cell.grid

If TRUE, the default, draw a tile-local grid across the chart area. The grid uses the current x/y scale major and minor breaks by default. If binwidth is finer than, and aligned with, those scale breaks, the cell grid uses the finer bin spacing while preserving the existing x/y breaks as grid lines. If scale breaks are unavailable, the grid falls back to the computed bin spacing.

cell.grid.colour, cell.grid.linewidth, cell.grid.linetype, cell.grid.alpha

Appearance of the tile-local cell grid. The default, ggplot2::waiver(), inherits from the current panel.grid.*.x and panel.grid.*.y theme elements. Explicit values override the inherited theme style.

Details

The stat accepts either x and y aesthetics, where y is humidity ratio in chart display units, or x and relhum, where relhum is relative humidity in percent. Relative humidity inputs inherit the plot unit system and pressure from ggpsychro(). Tiles default to a small gap and alpha = 0.85 so psychrometric grid lines remain visible. Tile bodies are clipped to the saturation line in psychrometric coordinates. When binwidth is used, each tile represents one dry-bulb and humidity-ratio cell aligned to boundary. The optional cell grid follows the chart's x/y breaks so it stays aligned with the visible dry-bulb and humidity-ratio grid. Choose a binwidth that evenly subdivides those breaks when a denser Marsh-style cell grid should still coincide with the existing x/y grid.

Computed variables

  • count: number of observations in each tile.

  • hours: same as count, named for hourly weather data.

  • value: aggregated value aesthetic when supplied.

  • width, height: tile dimensions after applying gap.

  • cell_xmin, cell_xmax, cell_ymin, cell_ymax: full bin boundaries.

Examples

d <- data.frame(
    dry_bulb = c(20.1, 20.4, 22.2, 22.5),
    relative_humidity = c(50, 52, 60, 62),
    cooling_load = c(1.2, 1.6, 3.4, 4.2)
)

ggpsychro(d, tdb_lim = c(15, 30), hum_lim = c(0, 20)) +
    geom_psychro_tile(
        aes(dry_bulb, relhum = relative_humidity, fill = after_stat(hours)),
        binwidth = c(2, 2)
    )


ggpsychro(d, tdb_lim = c(15, 30), hum_lim = c(0, 20)) +
    geom_psychro_tile(
        aes(dry_bulb, relhum = relative_humidity, value = cooling_load,
            fill = after_stat(value)),
        binwidth = c(2, 2),
        fun = "mean"
    )