Chart grids and styles

ggpsychro draws the dry-bulb grid, humidity-ratio grid, saturation curve, and psychrometric reference grids through the coordinate system installed by ggpsychro(). The default reference grids are drawn without labels. Add geom_psychro_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")

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

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)

Reference grid helpers

The reference grid helpers are:

Helper	Property
geom_psychro_grid_relhum()	Relative humidity
geom_psychro_grid_wetbulb()	Wet-bulb temperature
geom_psychro_grid_vappres()	Vapor pressure
geom_psychro_grid_specvol()	Specific volume
geom_psychro_grid_enthalpy()	Enthalpy

ggpsychro(tdb_lim = c(0, 50), hum_lim = c(0, 40)) +
    geom_psychro_grid_relhum() +
    geom_psychro_grid_wetbulb() +
    geom_psychro_grid_vappres() +
    geom_psychro_grid_specvol() +
    geom_psychro_grid_enthalpy()

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_psychro_grid_relhum(linewidth = 0.8, color = "black", label.size = 5) +
    scale_relhum_continuous(breaks = seq(25, 75, by = 25), minor_breaks = NULL) +
    geom_psychro_grid_wetbulb(color = "black", linewidth = 0.6, label = FALSE) +
    scale_wetbulb_continuous(breaks = seq(5, 30, by = 5), minor_breaks = NULL) +
    geom_psychro_grid_vappres(show = FALSE) +
    scale_specvol_continuous(labels = NULL) +
    geom_psychro_grid_enthalpy()

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.

Psychrometric protractor

geom_psychro_protractor() adds the ASHRAE-style sensible heat ratio and heat-moisture-ratio protractor in the chart mask area. The parent chart decides the orientation: regular charts place it in the upper-left mask area, while Mollier charts rotate the same protractor into the lower-right mask area.

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

Use scale to resize the whole protractor and a length-2 margin to adjust the horizontal and vertical mask-area offsets. Tick breaks and labels are controlled by guide_psychro_protractor().

ggpsychro(tdb_lim = c(0, 50), hum_lim = c(0, 30), mollier = TRUE) +
    psychro_preset("minimal") +
    geom_psychro_protractor(
        scale = 0.85,
        margin = c(0.06, 0.12),
        guide = guide_psychro_protractor(
            shr_breaks = c(0, 0.2, 0.4, 0.6, 0.8, 1),
            shr_minor_breaks = seq(0.1, 0.9, by = 0.1),
            ratio_labels = NULL
        )
    )

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_psychro_grid_relhum(label = FALSE) +
    theme(
        psychro.panel.grid.saturation = element_line(
            color = "black", linetype = 2
        ),
        psychro.panel.mask = ggplot2::element_polygon(fill = "gray90", color = NA)
    )