plotnine.geom_map

geom_map(
    mapping=None,
    data=None,
    *,
    stat="identity",
    position="identity",
    na_rm=False,
    inherit_aes=True,
    show_legend=None,
    raster=False,
    **kwargs
)

Draw map feature

The map feature are drawn without any special projections.

Parameters

mapping : aes = None

Aesthetic mappings created with aes. If specified and inherit_aes=True, it is combined with the default mapping for the plot. You must supply mapping if there is no plot mapping.

Aesthetic	Default value
geometry
alpha	1
color	'#111111'
fill	'#333333'
group
linetype	'solid'
shape	'o'
size	0.5
stroke	0.5

The bold aesthetics are required.

data : DataFrame = None

The data to be displayed in this layer. If None, the data from from the ggplot() call is used. If specified, it overrides the data from the ggplot() call.

stat : str | stat = "identity"

The statistical transformation to use on the data for this layer. If it is a string, it must be the registered and known to Plotnine.

position : str | position = "identity"

Position adjustment. If it is a string, it must be registered and known to Plotnine.

na_rm : bool = False

If False, removes missing values with a warning. If True silently removes missing values.

inherit_aes : bool = True

If False, overrides the default aesthetics.

show_legend : bool | dict = None

Whether this layer should be included in the legends. None the default, includes any aesthetics that are mapped. If a bool, False never includes and True always includes. A dict can be used to exclude specific aesthetis of the layer from showing in the legend. e.g show_legend={'color': False}, any other aesthetic are included by default.

raster : bool = False

If True, draw onto this layer a raster (bitmap) object even ifthe final image is in vector format.

**kwargs : Any = {}

Aesthetics or parameters used by the stat.

Notes

This geom is best suited for plotting a shapefile read into geopandas dataframe. The dataframe should have a geometry column.

Examples

import geopandas as gp
from plotnine import (
    ggplot,
    aes,
    geom_map,
    geom_text,
    labs,
    scale_fill_brewer,
    scale_x_continuous,
    scale_y_continuous,
    scale_size_continuous,
    coord_cartesian,
    element_rect,
    theme_void,
    theme,
)

The Territories of Westeros

Layering different features on a Map

Read data and select features in Westeros only.

continents = gp.read_file("data/lands-of-ice-and-fire/continents.shp")
islands = gp.read_file("data/lands-of-ice-and-fire/islands.shp")
lakes = gp.read_file("data/lands-of-ice-and-fire/lakes.shp")
rivers = gp.read_file("data/lands-of-ice-and-fire/rivers.shp")
political = gp.read_file("data/lands-of-ice-and-fire/political.shp")
wall = gp.read_file("data/lands-of-ice-and-fire/wall.shp")
roads = gp.read_file("data/lands-of-ice-and-fire/roads.shp")
locations = gp.read_file("data/lands-of-ice-and-fire/locations.shp")

westeros = continents.query('name=="Westeros"')
islands = islands.query('continent=="Westeros" and name!="Summer Islands"')
lakes = lakes.query('continent=="Westeros"')
rivers = rivers.query('continent=="Westeros"')
roads = roads.query('continent=="Westeros"')

wg = westeros.geometry[0]
bool_idx = [wg.contains(g) for g in locations.geometry]
westeros_locations = locations[bool_idx]
cities = westeros_locations[westeros_locations["type"] == "City"].copy()

Create map by placing the features in layers in an order that limits obstraction.

The GeoDataFrame.geometry.centroid property has the center coordinates of polygons, we use these to place the labels of the political regions.

# Gallery, maps

# colors
water_color = "#a3ccff"
wall_color = "white"
road_color = "brown"


# Create label text by merging the territory name and
# the claimant to the territory
def fmt_labels(names, claimants):
    labels = []
    for name, claimant in zip(names, claimants):
        if name:
            labels.append("{} ({})".format(name, claimant))
        else:
            labels.append("({})".format(claimant))
    return labels


def calculate_center(df):
    """
    Calculate the centre of a geometry

    This method first converts to a planar crs, gets the centroid
    then converts back to the original crs. This gives a more
    accurate
    """
    original_crs = df.crs
    planar_crs = "EPSG:3857"
    return df["geometry"].to_crs(planar_crs).centroid.to_crs(original_crs)


political["center"] = calculate_center(political)
cities["center"] = calculate_center(cities)

(
    ggplot()
    + geom_map(westeros, fill=None)
    + geom_map(islands, fill=None)
    + geom_map(political, aes(fill="ClaimedBy"), color=None, show_legend=False)
    + geom_map(wall, color=wall_color, size=2)
    + geom_map(lakes, fill=water_color, color=None)
    + geom_map(rivers, aes(size="size"), color=water_color, show_legend=False)
    + geom_map(roads, aes(size="size"), color=road_color, alpha=0.5, show_legend=False)
    + geom_map(cities, size=1)
    + geom_text(
        political,
        aes("center.x", "center.y", label="fmt_labels(name, ClaimedBy)"),
        size=8,
        fontweight="bold",
    )
    + geom_text(
        cities,
        aes("center.x", "center.y", label="name"),
        size=8,
        ha="left",
        nudge_x=0.20,
    )
    + labs(title="The Political Territories of Westeros")
    + scale_fill_brewer(type="qual", palette=8)
    + scale_x_continuous(expand=(0, 0, 0, 1))
    + scale_y_continuous(expand=(0, 1, 0, 0))
    + scale_size_continuous(range=(0.4, 1))
    + coord_cartesian()
    + theme_void()
    + theme(figure_size=(8, 12), panel_background=element_rect(fill=water_color))
)

Credit: cadaei of the cartographersguild website forum.

Source: The Territories of Westeros