Normalized column density PDFs of H I, HISA, and H₂ toward the giant filament regions. Each row shows the H I, HISA, and H₂ N-PDF toward one GMF region. Left panels: N-PDFs traced by H I emission. The distributions are derived from the H I column densities that have been corrected for optical depth and continuum emission. Middle panels: the N-PDFs of the gas traced by HISA. Right panels: H₂ N-PDFs traced by ¹³CO in units of hydrogen atoms per cm⁻². The green curves indicate a log-normal fit to the distributions. The blue vertical dashed and solid lines mark the column density threshold and mean column density, respectively.