cedarkit-plots 2026.7.0

A graph tool for CEMC/CMA.

cedarkit-plots

A plotting tool for meteorology data.

Install

Install using pip:

pip install cedarkit-plots

Or download the latest source code from GitHub and install manually.

Getting started

The following example uses CMA-GFS data to draw a 2m temperature contour fill plot.

Set some variables:

import pandas as pd

graph_name = "2m Temperature (C)"
system_name = "CMA-GFS"
start_time = pd.to_datetime("2024-11-09")
forecast_time = pd.to_timedelta("24h")

Get local data file path using reki:

from reki.data_finder import find_local_file

data_file_path = find_local_file(
    "cma_gfs_gmf/grib2/orig",
    start_time=start_time,
    forecast_time=forecast_time,
)

Load 2m temperature field from file and convert unit:

from reki.format.grib.eccodes import load_field_from_file

field_t_2m = load_field_from_file(
    data_file_path,
    parameter="2t",
) - 273.15

Create contour style, including levels and colormap. In this example, a NCL colormap embedded in the project is used.

import numpy as np
import matplotlib.colors as mcolors
from cedarkit.plots.colormap import get_ncl_colormap
from cedarkit.plots.style import ContourStyle

t_2m_level = [-24, -20, -16, -12, -8, -4, 0, 4, 8, 12, 16, 20, 24, 28, 32]

color_map = get_ncl_colormap("BlAqGrYeOrReVi200")
color_index = np.array([2, 12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132, 142, 152]) - 2
t_2m_color_map = mcolors.ListedColormap(color_map(color_index))

t_2m_style = ContourStyle(
    colors=t_2m_color_map,
    levels=t_2m_level,
    fill=True,
)

Create a build-in template EastAsiaMapTemplate. A template is a pre-defined layout to put title, text info, colorbar in some position.

from cedarkit.plots.domains import EastAsiaMapTemplate

domain = EastAsiaMapTemplate()

Create plot panel and plot the field:

from cedarkit.plots.chart import Panel

panel = Panel(domain=domain)
panel.plot(field_t_2m, style=t_2m_style)

Add title and colorbar:

domain.set_title(
    panel=panel,
    graph_name=graph_name,
    system_name=system_name,
    start_time=start_time,
    forecast_time=forecast_time,
)
domain.add_colorbar(panel=panel, style=t_2m_style)

Show the picture:

panel.show()

LICENSE

Copyright © 2021-2026, developers at cemc-oper.

cedarkit-plots is licensed under Apache License V2.0

Third party

cedarkit/plots/resources/map/china-shapefiles is from project dongli/china-shapefiles.

cedarkit/plots/resources/colormap/ncl is from project NCL.