dbname:             ../adcpdb/a_ex
        output:             ./contour
        step_size:          1        /* must be 1 for navigation */
        ndepth:             128
        time_ranges:        separate
        year_base=          2018

        option_list:
            pg_min=                50
            reference:             final_ship_ref

            regrid:         average
                            depth

                            grid number=    80
                            origin=         23
                            increment=      20


          flag_mask:        ALL_BITS
            end
          end
     @a_ex.tmg             /* explicit time ranges or of the form "@gridfile" */