Usage¶

map-nl currently has two classes to help you create a PC4 map of the Netherlands: MapNL and ChoroplethMapNL. ChoroplethMapNL a wrapper around folium.Choropleth, and MapNL is a wrapper around folium.GeoJson. Both require a pandas DataFrame with at least two columns; one containing the PC4 codes, and one containing a value to plot. For example:

pc4	WOZ
2343	200
3544	250
...	...

ChoroplethMapNL¶

ChoroplethMapNL allows you to create a PC4 choropleth map of the Netherlands.

An example is shown below.

import pandas as pd
from map_nl import ChoroplethMapNL

df = pd.read_csv("https://raw.githubusercontent.com/fpgmaas/map-nl/main/data/woz-pc4.csv")
m = ChoroplethMapNL(geojson_simplify_tolerance=0.0001).plot(
    df,
    pc4_column_name="pc4",
    value_column_name="WOZ",
    legend_name="Average WOZ Value"
)
m.save("map.html")

Any other keyword-arguments passed to plot() are passed on to folium.Choropleth. For example, in order to change the colorscale that is used to fill the polygons, you could do:

m = ChoroplethMapNL(geojson_simplify_tolerance=0.0001).plot(
    df,
    pc4_column_name="pc4",
    value_column_name="WOZ",
    legend_name="Average WOZ Value",
    fill_color = "OrRd"
)

For more customization options, see the documentation of folium.Choropleth.

MapNL¶

MapNL allows you to create a custom PC4 map of the Netherlands.

An example is shown below.

import pandas as pd
from map_nl import MapNL

def get_color(value):
    if not value:
        return "grey"
    if value > 500:
        return "green"
    else:
        return "blue"

def style(feature):
    return {"fillColor": get_color(feature.get("properties").get("WOZ"))}

df = pd.read_csv("data/woz-pc4.csv")
m = MapNL(geojson_simplify_tolerance=0.0001).plot(
    df, pc4_column_name="pc4", value_column_name="WOZ", style_function=style, name="WOZ value"
)
m.save("map.html")

The above example will color any PC4-areas with a average WOZ above 500 green, blue if it is below 500, and grey if no average WOZ was found.

Any other keyword-arguments passed to plot() are passed on to folium.GeoJson. For example, in order to modify the default tooltip, you can define your own and provide that to the plot() method:

tooltip = folium.GeoJsonTooltip(
    fields=["pc4_code", "gem_name", "WOZ"],
    aliases=["PC4:", "Gemeente:", "WOZ:"],
    localize=True,
    sticky=False,
    labels=True,
    style="""
        background-color: #F0EFEF;
        border: 3px solid black;
        border-radius: 10px;
        box-shadow: 10px;
    """,
    max_width=800,
)

m = MapNL(geojson_simplify_tolerance=0.0001).plot(
    df,
    pc4_column_name="pc4",
    value_column_name="WOZ",
    style_function=style,
    name="WOZ value",
    tooltip=tooltip
)

For more customization options, see the documentation of folium.GeoJson.

Customizing the map¶

Keyword arguments passed to the constructors of MapNL and ChoroplethMapNL are passed on to folium.Map. So for example, in order to change the starting zoom level of the map, one could do:

m = ChoroplethMapNL(geojson_simplify_tolerance=0.0001, zoom_start=7)

For more customization options, see the documentation of folium.Map.