Add road safety example

docs/examples/road_safety/app.py

@@ -0,0 +1,41 @@
+import webbrowser
+
+import h3
+import pandas as pd
+from maplibre import Layer, Map, MapOptions
+from maplibre.sources import GeoJSONSource
+from maplibre.utils import df_to_geojson, get_bounds
+
+RESOLUTION = 5
+
+road_safety = pd.read_csv(
+    "https://raw.githubusercontent.com/visgl/deck.gl-data/master/examples/3d-heatmap/heatmap-data.csv"
+).dropna()
+
+road_safety["h3"] = road_safety.apply(
+    lambda x: h3.geo_to_h3(x["lat"], x["lng"], resolution=RESOLUTION), axis=1
+)
+
+df = road_safety.groupby("h3").h3.agg("count").to_frame("count").reset_index()
+
+df["hexagon"] = df.apply(
+    lambda x: [h3.h3_to_geo_boundary(x["h3"], geo_json=True)], axis=1
+)
+
+source = GeoJSONSource(
+    data=df_to_geojson(df, "hexagon", geometry_type="Polygon", properties=["count"])
+)
+bounds = get_bounds(source.data)
+
+m = Map(MapOptions(bounds=bounds))
+m.add_layer(
+    Layer(id="road-safety", type="line", source=source, paint={"line-color": "yellow"})
+)
+m.add_tooltip("road-safety", "count")
+
+filename = "/tmp/road_safety.html"
+with open(filename, "w") as f:
+    f.write(m.to_html())
+
+
+webbrowser.open(filename)