curv_cols: Convert Curvature Values to Binary Colors for Visualization

In bbuchsbaum/neurosurf: Data structures and visualization for surface-based neuroimaging data

Convert Curvature Values to Binary Colors for Visualization

Description

This function maps a vector of surface curvature values (e.g., mean curvature) to a binary color scheme, typically used to distinguish gyri (outward folds) from sulci (inward folds) on a brain surface visualization.

Usage

curv_cols(vals, incol = "#B3B3B3", outcol = "#404040")

Arguments

vals	A numeric vector containing curvature values for each vertex on the surface.
incol	A character string specifying the hex color code to represent vertices with curvature values *greater than* the median curvature. Default is "#B3B3B3" (light gray).
outcol	A character string specifying the hex color code to represent vertices with curvature values *less than or equal to* the median curvature. Default is "#404040" (dark gray).

Details

Surface curvature provides information about the local shape of the surface. Mean curvature is often used, where positive values typically indicate outward curvature (gyri) and negative values indicate inward curvature (sulci). This function simplifies the curvature map into two colors based on whether the value is above or below the median curvature, providing a quick visual distinction between these features. Note the default coloring assigns 'incol' to values *above* the median and 'outcol' to values *at or below* the median. You might need to adjust 'incol' and 'outcol' depending on the specific interpretation of curvature values in your data (e.g., if positive values represent sulci).

Value

A character vector of the same length as 'vals', containing hex color codes based on the binary classification of curvature values relative to the median.

See Also

curvature, view_surface

Examples

# Generate some example curvature values
set.seed(123)
curvature_values <- rnorm(100, mean = 0, sd = 0.1)

# Get binary colors using default light/dark gray
gray_colors <- curv_cols(curvature_values)
table(gray_colors)

# Use different colors (e.g., red for above median, blue for below)
red_blue_colors <- curv_cols(curvature_values, incol = "#FF0000", outcol = "#0000FF")
table(red_blue_colors)

bbuchsbaum/neurosurf documentation built on June 10, 2025, 8:22 p.m.