RHT analysis performed on the HI brightness temperature at each velocity channel and integrated over the velocity range where the filaments are evident. The velocity range for each field is given below the images showing the RHT back-projections in the upper part of the figure. The lower part of the figure shows the corresponding distribution of the relative orientation of the HI filaments with respect to the Galactic plane as in Figs. 4–6. The RHT input parameters are D_K =10′, D_W =100′, and Z = 0.8 (see main text).