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ggpsychro draws the dry-bulb grid, humidity-ratio grid, saturation curve, and psychrometric reference grids through coord_psychro(). The default reference grids are drawn without labels. Add geom_grid_*() helpers when a grid should be explicit and labelled.

Presets

psychro_preset() applies a named collection of scales, labelled reference grids, and a matching theme. The built-in presets are "ashrae" and "minimal".

ggpsychro(tdb_lim = c(0, 50), hum_lim = c(0, 30)) +
    psychro_preset("ashrae")

ASHRAE-style psychrometric chart with labelled reference grids.

ggpsychro(tdb_lim = c(0, 50), hum_lim = c(0, 40)) +
    psychro_preset("minimal")

Minimal psychrometric chart with selected labelled reference grids.

Use labels = FALSE when you want the preset’s grid visibility and theme but no grid labels.

ggpsychro(tdb_lim = c(0, 50), hum_lim = c(0, 30)) +
    psychro_preset("ashrae", labels = FALSE)

ASHRAE-style psychrometric chart with reference grid labels hidden.

Reference grid helpers

The reference grid helpers are:

Helper Property
geom_grid_relhum() Relative humidity
geom_grid_wetbulb() Wet-bulb temperature
geom_grid_vappres() Vapor pressure
geom_grid_specvol() Specific volume
geom_grid_enthalpy() Enthalpy

Psychrometric chart with relative humidity, wet-bulb, vapor pressure, specific volume, and enthalpy grids.

These helpers do not add data layers. They update the psychrometric coordinate metadata so the panel background can draw or hide the selected grid.

Breaks, labels, and style

Each reference grid has a matching scale_*_continuous() function. Use these scales to customize breaks, minor breaks, limits, and labels.

ggpsychro(tdb_lim = c(0, 50), hum_lim = c(0, 40)) +
    geom_grid_relhum(linewidth = 0.8, color = "black", label.size = 5) +
    scale_relhum_continuous(breaks = seq(25, 75, by = 25), minor_breaks = NULL) +
    geom_grid_wetbulb(color = "black", linewidth = 0.6, label = FALSE) +
    scale_wetbulb_continuous(breaks = seq(5, 30, by = 5), minor_breaks = NULL) +
    geom_grid_vappres(show = FALSE) +
    scale_specvol_continuous(labels = NULL) +
    geom_grid_enthalpy()

Psychrometric chart with custom grid breaks, labels, and line styles.

Line style arguments go directly to ggplot2::element_line(). Label style arguments use a label. prefix, such as label.size, label.color, and label.vjust.

Theme elements

ggpsychro adds psychrometric theme elements for panel masks and reference grids. Use these with regular theme() calls.

ggpsychro(tdb_lim = c(0, 50), hum_lim = c(0, 30)) +
    geom_grid_relhum(label = FALSE) +
    theme(
        psychro.panel.grid.saturation = element_line(
            color = "black", linetype = 2
        ),
        psychro.panel.mask = element_polygon(fill = "gray90", color = NA)
    )

Psychrometric chart with custom saturation line and gray panel mask theme elements.