GRIB - Layout with 3 Maps

# (C) Copyright 2017- ECMWF.
#
# This software is licensed under the terms of the Apache Licence Version 2.0
# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
#
# In applying this licence, ECMWF does not waive the privileges and immunities
# granted to it by virtue of its status as an intergovernmental organisation
# nor does it submit to any jurisdiction.
#

# ------------------------------------------------------------------
# Demonstrates how to use a Display Window icon to
# produce a plot with 3 maps consisting of a) a 24h
# forecast, b) a 96h forecast and c) their difference
# ------------------------------------------------------------------

import metview as mv

# read the 24h forecast GRIB data from file
filename = "t_fc24.grib"
if mv.exist(filename):
    f24 = mv.read(filename)
else:
    f24 = mv.gallery.load_dataset(filename)

# read the 96h forecast GRIB data from file
filename = "t_fc96.grib"
if mv.exist(filename):
    f96 = mv.read(filename)
else:
    f96 = mv.gallery.load_dataset(filename)

# filter just the 850hPa level
t_fc24 = mv.read(data=f24, levelist=850)
t_fc96 = mv.read(data=f96, levelist=850)

# we will use the same view in all the plots, but we could also use different
# views for each plot
view = mv.geoview(
    map_area_definition="corners", area=[23.7, -31.6, 83.0, 89.6]  # rough European area
)

# each page in the layout contains its position plus its view specification
# (could also be a Cross Section View, for example). Defaults are=
# top=0, bottom=100, left=0, right=100  in percent of layout height and width

page_24 = mv.plot_page(bottom=45, right=50, view=view)

page_96 = mv.plot_page(bottom=45, left=50, view=view)

page_diff = mv.plot_page(top=50, left=11, view=view)


# contouring specifications

t_shade = mv.mcont(
    contour="off",
    contour_hilo="off",
    contour_label="off",
    contour_level_selection_type="interval",
    contour_interval=4,
    contour_shade="on",
    contour_shade_min_level=-52,
    contour_shade_max_level=48,
    contour_shade_method="area_fill",
    contour_shade_colour_method="list",
    contour_shade_colour_list=[
        "rgb(0.88,0.2,0.88)",
        "rgb(0.68,0.2,0.68)",
        "rgb(0.48,0.2,0.48)",
        "rgb(0.28,0.2,0.28)",
        "rgb(0.2,0,0.4)",
        "rgb(0.35,0,0.5)",
        "blue_purple",
        "greenish_blue",
        "rgb(0,0.8,1.0)",
        "blue_green",
        "bluish_green",
        "yellow_green",
        "greenish_yellow",
        "rgb(1,1,0.5)",
        "yellow",
        "orange_yellow",
        "yellowish_orange",
        "rgb(1,0.45,0)",
        "red",
        "rgb(0.8,0,0)",
        "burgundy",
        "rose",
        "magenta",
        "rgb(1,0.5,1)",
        "rgb(1,0.75,1)",
    ],
)

pos_shade = mv.mcont(
    legend="on",
    contour_line_colour="grey",
    contour_highlight="off",
    contour_level_selection_type="level_list",
    contour_level_list=[0.5, 1, 2, 4, 10, 20],
    contour_shade="on",
    contour_shade_method="area_fill",
    contour_shade_max_level_colour="red",
    contour_shade_min_level_colour="orange_yellow",
    contour_shade_colour_direction="clockwise",
)

neg_shade = mv.mcont(
    legend="on",
    contour_line_colour="grey",
    contour_highlight="off",
    contour_level_selection_type="level_list",
    contour_level_list=[-20, -10, -4, -2, -1, -0.5],
    contour_shade="on",
    contour_shade_method="area_fill",
    contour_shade_max_level_colour="greenish_yellow",
    contour_shade_min_level_colour="blue",
    contour_shade_colour_direction="clockwise",
)


# when we have multiple pages in a layout, the default titles can be a bit too long
# for the available space; hence we will construct shorter titles, using automated
# fields as far as possible. We could also use Metview's own date/string formatting
# routines to construct 'nicer' dates in the titles

title_fc = mv.mtext(
    text_line_1="<grib_info key='name'/> at <grib_info key='level'/> hPa= "
    + "<grib_info key='dataDate'/> + <grib_info key='step'/>"
    + " VT= <grib_info key='validityDate'/>",
    text_font_size=0.45,
)

title_diff = mv.mtext(text_line_1="Difference= FC96 - FC24", text_font_size=0.45)


dw = mv.plot_superpage(
    # the order of these pages is used when indexing them in the plot() command
    pages=[page_24, page_96, page_diff]
)

# define the output plot file
mv.setoutput(mv.pdf_output(output_name="layoutx3"))

# plot the data into each page using a single plot command; note that
# we defined 3 pages, so they are indexed by 0, 1, 2
mv.plot(
    dw[0],
    t_fc24,
    t_shade,
    title_fc,
    dw[1],
    t_fc96,
    t_shade,
    title_fc,
    dw[2],
    t_fc96 - t_fc24,
    neg_shade,
    pos_shade,
    title_diff,
)