mgrib(grib_field_position = 1,
grib_input_file_name = "period_of_swell.grib")
mcont(contour_shade_colour_method = "list",
contour_label_colour = "black",
contour_line_colour = "white",
contour_reference_level = 0.00,
contour_label_format = "(F4.1)",
contour_label = "off",
contour_min_level = 0.00,
contour_shade_method = "area_fill",
legend = "on",
contour_shade_colour_list = ["blue", "greenish_blue",...,"brown", "charcoal"],
contour_level_selection_type = "level_list",
contour_shade = "on",
contour_level_list = [0.00, 3.50,...,17.00, 18.50],
contour_hilo = "off",
contour_highlight = "off",
contour_shade_min_level = 0.00)