epa-regions-python

EPA regions from Natural Earth data with GeoPandas / regionmask.

Code

python -m epa_regions -r 50m --states-only --save

Installation

conda activate ...
conda install -c conda-forge geopandas regionmask pooch pyogrio
pip install epa-regions

Usage

import epa_regions

# GeoPandas GeoDataFrame
epa = epa_regions.get(resolution="50m")

# Convert to regionmask Regions for use with gridded data
epa = epa_regions.to_regionmask(epa)

Point data

Code

import geopandas as gpd
import matplotlib.pyplot as plt
import numpy as np

import epa_regions

rng = np.random.default_rng(seed=123)

epa = epa_regions.get(resolution="50m")

# CONUS
lonmin, lonmax = -125, -66
latmin, latmax = 24, 50
n = 250
lon = rng.uniform(lonmin, lonmax, n)
lat = rng.uniform(latmin, latmax, n)
points = gpd.GeoDataFrame(
    geometry=gpd.points_from_xy(lon, lat, crs="EPSG:4326")
)

fig, ax = plt.subplots(constrained_layout=True, figsize=(4, 2.5))

epa.plot(column="number", ax=ax, alpha=0.6)
points.sjoin(epa, predicate="within").plot(column="number", ax=ax, ec="0.3", lw=1)

ax.set(xlim=(lonmin, lonmax), ylim=(latmin, latmax))
ax.axis("off")

fig.savefig("points.png", dpi="figure", bbox_inches="tight")

Gridded data

Code

import cartopy.crs as ccrs
import cartopy.feature as cfeature
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import xarray as xr

import epa_regions

epa = epa_regions.to_regionmask(epa_regions.get(resolution="50m"))

# CONUS
lonmin, lonmax = -125, -66
latmin, latmax = 24, 50

ds = (
    xr.tutorial.open_dataset("air_temperature")
    .sel(lon=slice(lonmin + 360, lonmax + 360), lat=slice(latmax, latmin))
)
mask = epa.mask(ds.isel(time=0))

proj = ccrs.LambertConformal(central_longitude=-100)
tran = ccrs.PlateCarree()

fig = plt.figure(figsize=(6, 6), constrained_layout=True)

ax = fig.add_subplot(3, 1, (1, 2), projection=proj)

mask.plot.pcolormesh(
    levels=np.arange(mask.min() - 0.5, mask.max() + 1),
    ax=ax,
    transform=ccrs.PlateCarree(),
    cmap="tab10",
    cbar_kwargs=dict(
        orientation="horizontal",
        fraction=0.075,
        pad=0.05,
        ticks=np.arange(mask.min(), mask.max() + 1),
        format="R{x:.0f}",
        label="EPA Region",
    ),
)

ax.add_feature(cfeature.STATES, linewidth=0.7, edgecolor="0.3")
ax.coastlines()
ax.set_extent([lonmin, lonmax - 2, latmin, latmax], crs=tran)
ax.set_title("")

ax = fig.add_subplot(3, 1, 3)

(dt,) = np.unique(ds.time.diff("time"))

window = pd.Timedelta("30D")
(
    ds["air"].groupby(mask)
    .mean()
    .rolling(time=int(window / dt), center=True)
    .mean()
    .plot(
        hue="mask",
        ax=ax,
        add_legend=False,
    )
)

ax.set_xlabel("")
ax.text(
    0.01,
    0.97,
    f"{window.total_seconds() / 86400:g}-day rolling mean",
    ha="left",
    va="top",
    transform=ax.transAxes,
    fontsize=11,
)

fig.savefig("gridded.png", dpi="figure", bbox_inches="tight")