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Plot Trade-off Analysis Between Two Objectives

Source: R/analysis-tradeoff.R
plot_tradeoff.Rd

Creates a 2D scatterplot visualizing trade-offs between two ecosystem service families or indicators. Optionally overlays the Pareto optimal frontier to highlight non-dominated solutions.

Usage

plot_tradeoff(
  data,
  x,
  y,
  color = NULL,
  size = NULL,
  pareto_frontier = FALSE,
  label = NULL,
  xlab = NULL,
  ylab = NULL,
  title = NULL
)

Arguments

data

An sf object or data.frame containing the parcels to visualize

x

Character string specifying the column name for the x-axis variable

y

Character string specifying the column name for the y-axis variable

color

Optional character string specifying a column for color mapping (e.g., to show a third dimension)

size

Optional character string specifying a column for size mapping

pareto_frontier

Logical indicating whether to overlay the Pareto optimal frontier. Requires an is_optimal column in the data (default: FALSE)

label

Optional character string specifying column for point labels

xlab

Custom x-axis label (default: variable name)

ylab

Custom y-axis label (default: variable name)

title

Custom plot title (default: auto-generated)

Value

A ggplot2 object that can be further customized or printed

Details

## Trade-off Analysis

Trade-off plots reveal relationships between ecosystem services: - **Synergies**: Both variables increase together (positive correlation) - **Trade-offs**: One increases while the other decreases (negative correlation) - **No relationship**: Variables are independent

## Pareto Frontier

When pareto_frontier = TRUE, Pareto optimal parcels are highlighted and connected to show the efficiency frontier. These parcels represent the best possible trade-offs - improving one objective requires sacrificing another.

## Visualization Tips

- Use color to add a third dimension (e.g., color by fire risk) - Use size to emphasize important parcels (e.g., size by area) - Use label to identify specific parcels of interest - Combine with faceting for multi-scenario comparisons

Examples

if (FALSE) { # \dontrun{
# Load demo dataset
data("massif_demo_units")

# Basic trade-off plot: carbon vs biodiversity
plot_tradeoff(
  massif_demo_units,
  x = "family_C",
  y = "family_B"
)

# Add color for a third dimension (production)
plot_tradeoff(
  massif_demo_units,
  x = "family_C",
  y = "family_B",
  color = "family_P",
  title = "Carbon-Biodiversity Trade-off (colored by Production)"
)

# Overlay Pareto frontier
result <- identify_pareto_optimal(
  massif_demo_units,
  objectives = c("family_C", "family_B", "family_P"),
  maximize = rep(TRUE, 3)
)

plot_tradeoff(
  result,
  x = "family_C",
  y = "family_B",
  pareto_frontier = TRUE
)

# With labels for Pareto optimal parcels
plot_tradeoff(
  result,
  x = "family_C",
  y = "family_B",
  pareto_frontier = TRUE,
  label = "name"
)

# Multiple trade-off comparisons
library(patchwork)
p1 <- plot_tradeoff(massif_demo_units, "family_C", "family_B")
p2 <- plot_tradeoff(massif_demo_units, "family_C", "family_P")
p3 <- plot_tradeoff(massif_demo_units, "family_B", "family_P")
p1 + p2 + p3
} # }