add_status_tree         Add column 'status_tree' based on the status of
                        all stems of each tree.
add_subquad             Add column 'subquadrat' based on 'QX' and 'QY'
                        coordinates.
add_var                 Add columns 'lx/ly', 'QX/QY', 'index',
                        'col/row', 'hectindex', 'quad', 'gx/gy'.
fgeo_elevation          Create elevation data.
pick_drop               Pick and drop rows from _ViewFullTable_,
                        _tree_, and _stem_ tables.
pick_main_stem          Pick the main stem or main stemid(s) of each
                        tree in each census.
read_vft                Import _ViewFullTable_ or _ViewTaxonomy_ data
                        from a .tsv or .csv file.
sanitize_vft            Fix common problems in _ViewFullTable_ and
                        _ViewTaxonomy_ data.
