Clay activity chart

Draws a clay activity chart—plasticity index vs clay percentage—following. Reference lines for eight activity values are fitted by linear regression on built-in data and plotted as styled lines. Activity values are labelled directly on the chart and/or shown in a legend.

Usage

clay_activity(
  show.legend = T,
  legend.pos = "top",
  show.labels = T,
  labels.pos = "high",
  lang = "en"
)

Arguments

show.legend

Logical. If TRUE (default) a legend mapping line type to activity value is shown; if FALSE the legend is suppressed.

legend.pos

Character. Position of the legend passed to theme(legend.position = ...). Default "top".

show.labels

Logical. If TRUE (default) activity values are annotated directly on the reference lines; if FALSE` labels are omitted.

labels.pos

Character. Position of the direct labels: "high" (default) places labels near the top of the plot; "low" places labels near the bottom.

lang

Character. Language for axis titles: "en" (default) for English, "es" for Spanish.

Value

A ggplot object with clay percentage on the x-axis (0–100) and plasticity index on the y-axis (0–500), containing the eight reference activity lines and optional direct labels.

References

Das, B. M., & Sobhan, K. (2018). Principles of geotechnical engineering (Ninth edition). Cengage Learning.

See also

Other classification plots, soil mechanics: Casagrande_chart(), soil_collapse(), soil_expansion(), soil_swelling(), ternary_shepard(), ternary_usda()

Examples

# Reference chart only (no sample data)
clay_activity()


# Spanish axis labels, no legend
clay_activity(show.legend = FALSE, lang = "es")