fp_scaled_axis: Create a secondary GGPlot2 axis with scaled units and factor...

In adas.utils: Design of Experiments and Factorial Plans Utilities

Create a secondary GGPlot2 axis with scaled units and factor names

Description

This is useful when creating contour plots for the FP response surface or factors interaction plots. It allows to add secondary axes that use the scaled factor units rather than the coded units (in range -1, 1).

Usage

fp_scaled_axis(fp, fct)

Arguments

fp	The factorial plan object
fct	The standard name of the factor as a string (e.g. "A", or "B", etc.)

Value

A ggplot2::sec_axis object

See Also

fp_name() fp_scale()

Examples

library(tidyverse)
fp <- fp_design_matrix(2, rep=3) %>%
  fp_add_names(A="Temperature (°C)", B="Pressure (bar)") %>%
  fp_add_scale(A=c(20,30), B=c(2, 3))
fp$Y <- ccd_experiment_yield$base
fp.lm <- lm(Y~A*B, data=fp)

# Interaction plot:
fp %>%
  mutate(
    pred = predict(fp.lm),
    B=factor(B)
  ) %>%
  ggplot(aes(x=A, y=pred, color=B)) +
  geom_line() +
  scale_x_continuous(sec.axis = fp_scaled_axis(fp, "A"))+
  scale_color_discrete(labels = fp_scale(fp, "B")) +
  labs(color=fp_name(fp, "B"), y="Yield")

expand.grid(
  A = seq(-1, 1, length.out=100),
  B = seq(-1, 1, length.out=100)
) %>% {
  mutate(., Y=predict(fp.lm, newdata=.))
} %>%
  ggplot(aes(x=A, y=B, z=Y)) +
  geom_contour_filled() +
  scale_x_continuous(sec.axis = fp_scaled_axis(fp, "A")) +
  scale_y_continuous(sec.axis = fp_scaled_axis(fp, "B")) +
  labs(fill="Yield")

adas.utils documentation built on Nov. 15, 2025, 1:08 a.m.