safe_edge_label_position: Adjust Edge Label Positions to Avoid Overlapping Labels

Description

Move the edge labels away from path intersections.

Usage

safe_edge_label_position(
  object,
  layout = NULL,
  default_pos = 0.5,
  tolerance = 0.05,
  update_plot = TRUE
)

Value

If object is a lavaan-class object, it returns a named numeric vector of edge positions to be used by set_edge_label_position(). If object is a qgraph object and update_plot is TRUE, it returns a qgraph object with the adjusted edge label positions. Otherwise, it returns a named vector of the position to be adjusted, as for a lavaan-class object.

Arguments

object: It can be the output of lavaan::sem() or lavaan::lavaan(), or a lavaan-class object. The model must have a beta matrix of the structural path. It can also be a qgraph object generated by semPlot::semPaths().
layout: A layout matrix. Required if object is a lavaan-class object. Ignored if object is a qgraph object.
default_pos: Used if object is a lavaan-class object. The default position of an edge label. If this position is "safe" (not on the intersection between paths), it will be used. Ignored if object is a qgraph object.
tolerance: If the distance between a position and an intersection is greater than this distance, then a position is considered safe and will not be adjusted.
update_plot: Logical. Used on if object is a qgraph object. If TRUE, the function returns a modified qgraph object. If FALSE, the function returns a named vector of the new positions.

Details

This function identify all intersection points between two paths in a model, and set the position of an edge label to the mid-point of a line segment between an intersection point and the another intersection point or the origin/destination of a path.

This function is intended for having a "likely" readable graph with as little user-intervention as possible. If precise control of the edge label positions is desired, use set_edge_label_position().

Examples

Run this code


library(lavaan)
library(semPlot)
# Create a dummy dataset
mod_pa <-
"
m11 ~ c1 + x1
m12 ~ c2 + m11 + m21
m21 ~ c1 + x1
m22 ~ c1 + m21 + m11
y ~ m12 + m22 + x1
"
fit <- lavaan::sem(
          mod_pa,
          do.fit = FALSE
        )
dat <- simulateData(
          parameterTable(fit),
          sample.nobs = 500,
          seed = 1234
        )
fit <- lavaan::sem(
          mod_pa,
          dat
        )
# Set the layout
m <- auto_layout_mediation(
        fit,
        exclude = c("c1", "c2", "c3")
      )
pos_new <- safe_edge_label_position(
                fit,
                layout = m
              )
pos_new
pm <- semPlotModel(fit) |> drop_nodes(c("c1", "c2"))
p <- semPaths(
          pm,
          whatLabels = "est",
          layout = m,
          DoNotPlot = TRUE
        )
# Three labels overlap with each other
plot(p)
# Update the plot
p_safe <- p |> safe_edge_label_position()
# Three labels do not overlap in this plot
plot(p_safe)
# Set the position manually
p_safe2 <- p |>
            set_edge_label_position(pos_new)
plot(p_safe2)