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41 changes: 12 additions & 29 deletions examples/gallery/maps/choropleth_map.py
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"""

# %%
import geodatasets
import geopandas as gpd
import pygmt

# Read the example dataset provided by geodatasets.
gdf = gpd.read_file(geodatasets.get_path("geoda airbnb"))
print(gdf.head())
provider = "https://naciscdn.org/naturalearth"
world = gpd.read_file(f"{provider}/110m/cultural/ne_110m_admin_0_countries.zip")

# %%
fig = pygmt.Figure()
# The dataset contains different attributes, here we focus on the population within
# the different countries (column "POP_EST") for the continent "Africa".
world["POP_EST"] *= 1e-6
africa = world[world["CONTINENT"] == "Africa"].copy()

fig.basemap(
region=gdf.total_bounds[[0, 2, 1, 3]],
projection="M6c",
frame="+tPopulation of Chicago",
)

# The dataset contains different attributes, here we select the "population" column to
# plot.
fig = pygmt.Figure()
fig.basemap(region=[-19.5, 53, -37.5, 38], projection="M10c", frame="+n")

# First, we define the colormap to fill the polygons based on the "population" column.
pygmt.makecpt(
cmap="acton",
series=[gdf["population"].min(), gdf["population"].max(), 10],
continuous=True,
reverse=True,
)
# First, we define the colormap to fill the polygons based on the "POP_EST" column.
pygmt.makecpt(cmap="acton", series=(0, 100), reverse=True)

# Next, we plot the polygons and fill them using the defined colormap. The target column
# is defined by the aspatial parameter.
fig.plot(
data=gdf,
pen="0.3p,gray10",
fill="+z",
cmap=True,
aspatial="Z=population",
)
fig.plot(data=africa, pen="0.8p,gray50", fill="+z", cmap=True, aspatial="Z=POP_EST")

# Add colorbar legend.
fig.colorbar(frame="x+lPopulation", position="jML+o-0.5c+w3.5c/0.2c")
fig.colorbar(frame="x+lPopulation (millions)", position="jML+o2c/-2.5c+w5c+ef0.2c+ml")

fig.show()