Monthly Mean with Gradient Shading Example

#Metview Macro

#  **************************** LICENSE START ***********************************
# 
#  Copyright 2020 ECMWF. This software is distributed under the terms
#  of the Apache License version 2.0. In applying this license, ECMWF does not
#  waive the privileges and immunities granted to it by virtue of its status as
#  an Intergovernmental Organization or submit itself to any jurisdiction.
# 
#  ***************************** LICENSE END ************************************
# 

# get data
use_mars = 0 # 0 or 1
if use_mars then
    # retrieve data from MARS   
    t = retrieve(
        class   : "era5",
        stream  : "moda",
        levtype : "sfc",
        param   : "2t",
        date    : 20200101,
        time    : 0,
        grid    : [1,1]
    )
else
    # read data from GRIB file
    t = read("era5_t2_jan.grib")
end if

# define coastlines
coast = mcoast(
    map_grid  : "off",
    map_label : "off"
    )

# define view
view = geoview(
    map_projection     : "robinson",
    subpage_y_position : 14,
    subpage_y_length   : 86,
    coastlines         : coast,
    page_frame: "off",
    subpage_frame: "off"
    )

# define contouring
cont = mcont(
    legend                        : "on",
    contour                       : "off",
    contour_level_selection_type  : "level_list",
    contour_level_list            : [-45,-20,0,20,45],
    contour_label                 : "off",
    contour_shade                 : "on",
    contour_shade_colour_method   : "gradients",
    contour_shade_method          : "area_fill",
    contour_gradients_colour_list : ["RGB(0.1532,0.1187,0.5323)","RGB(0.5067,0.7512,0.8188)","RGB(0.9312,0.9313,0.9275)","RGB(0.9523,0.7811,0.3104)","RGB(0.594,0.104,0.104)"],
    contour_gradients_step_list   : 20
    )

# define legend
legend = mlegend(
    legend_box_mode        : "positional",
    legend_text_font_size  : 0.4,
    legend_box_y_position  : 1,
    legend_box_y_length    : 1.5,
    legend_entry_border    : "off",
    legend_label_frequency : 10
    )

# define title
title = mtext(
            text_line_1: "ERA5 T2 Monthly Mean 2020 January 0UTC",
            text_font_size: 0.6)

# define the output plot file
setoutput(pdf_output(output_name : 'gradient_shading'))

# generate plot
plot(view, t, cont, title, legend)

"""
Contouring with gradient shading
"""

#  **************************** LICENSE START ***********************************
#
#  Copyright 2020 ECMWF. This software is distributed under the terms
#  of the Apache License version 2.0. In applying this license, ECMWF does not
#  waive the privileges and immunities granted to it by virtue of its status as
#  an Intergovernmental Organization or submit itself to any jurisdiction.
#
#  ***************************** LICENSE END ************************************
#

import metview as mv

# get data
use_mars = False
if use_mars:
    # retrieve data from MARS
    t = mv.retrieve(
        class_="era5",
        stream="moda",
        levtype="sfc",
        param="2t",
        date=20200101,
        time=0,
        grid=[1, 1],
    )
else:
    # read data from GRIB file
    t = mv.read("era5_t2_jan.grib")

# define coastlines
coast = mv.mcoast(map_grid="off", map_label="off")

# define view
view = mv.geoview(
    map_projection="robinson",
    subpage_y_position=14,
    subpage_y_length=86,
    coastlines=coast,
    page_frame="off",
    subpage_frame="off",
)

# define contouring
cont = mv.mcont(
    legend="on",
    contour="off",
    contour_level_selection_type="level_list",
    contour_level_list=[-45, -20, 0, 20, 45],
    contour_label="off",
    contour_shade="on",
    contour_shade_colour_method="gradients",
    contour_shade_method="area_fill",
    contour_gradients_colour_list=[
        "RGB(0.1532,0.1187,0.5323)",
        "RGB(0.5067,0.7512,0.8188)",
        "RGB(0.9312,0.9313,0.9275)",
        "RGB(0.9523,0.7811,0.3104)",
        "RGB(0.594,0.104,0.104)",
    ],
    contour_gradients_step_list=20,
)

# define legend
legend = mv.mlegend(
    legend_box_mode="positional",
    legend_text_font_size=0.4,
    legend_box_y_position=1,
    legend_box_y_length=1.5,
    legend_entry_border="off",
    legend_label_frequency=10,
)

# define title
title = mv.mtext(
    text_line_1="ERA5 T2 Monthly Mean 2020 January 0UTC", text_font_size=0.6
)

# define the output plot file
mv.setoutput(mv.pdf_output(output_name="gradient_shading"))

# generate plot
mv.plot(view, t, cont, title, legend)