sbn_change_dir          Change the upstream/downstream direction of an
                        SBN
sbn_create              Create SBNs
sbn_down_dir            Convert to a downstream directed network
sbn_get_downstream      Find all downstream nodes
sbn_get_hw              Find all headwater nodes
sbn_get_outlet          Find river mouth node
sbn_get_upstream        Find all nodes upstream of a given node
sbn_strahler            Get node strahler order
sbn_to_mtx              Convert network to various adjacency/distance
                        matrix formats
