Two-dimensional histograms of filament curvatures C in central parts of the filaments versus changes in curvature radius, characterized by the ratio R_C for curvatures at the closest positions off the filaments. To the left we display ratios R_C derived fromH I column densities, and to the right R_C ratios are given for FIR intensities at 857 GHz. Top panels display distributions restricted to high Galactic latitudes. Bottom panels: from all sky data.