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GRIB - Grid Values and Contour Levels
# (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 show the field grid values and define a
# list of contour levels.
# ------------------------------------------------------------------------
import metview as mv
# read the input grib file
filename = "t850.grb"
if mv.exist(filename):
my_data = mv.read(filename)
else:
my_data = mv.gallery.load_dataset(filename)
# set up the coastlines
my_coast = mv.mcoast(
map_coastline_land_shade_colour="CREAM",
map_grid_colour="TAN",
map_grid="ON",
map_coastline_colour="TAN",
map_coastline_land_shade="ON",
)
# set up the geographical view
my_view = mv.geoview(
map_area_definition="CORNERS",
map_projection="CYLINDRICAL",
area=[25.00, -20.00, 65.00, 50.00],
coastlines=my_coast,
)
# set up the contour so that grid values are shown
my_contour = mv.mcont(
contour_grid_value_plot="ON",
contour_level_selection_type="LEVEL_LIST",
contour_level_list=[-20, -10, -5, -2.5, -1, -0.5, 0, 0.5, 1, 2.5, 5, 10, 20],
contour_grid_value_height=0.30,
contour_grid_value_plot_type="BOTH",
contour_grid_value_marker_height=0.20,
contour_line_colour="GREY",
contour_highlight="OFF",
contour_line_thickness=2,
contour_label="OFF",
contour_grid_value_lon_frequency=10,
contour_grid_value_lat_frequency=10,
legend="OFF",
)
# set-up the title
my_title = mv.mtext(
text_font_size=0.70,
text_lines=[
"Display the grid values and user-defined list of contour levels:",
"[-20, -10, -5, -2.5, -1, -0.5, 0, 0.5, 1, 2.5, 5, 10, 20]",
"",
],
text_justification="LEFT",
text_colour="CHARCOAL",
)
# define the output plot file
mv.setoutput(mv.pdf_output(output_name="contour3"))
# plot the data onto the map
mv.plot(my_view, my_data, my_contour, my_title)