Create HeatMap as suggested in #213

Author: Martin Journois

folium/plugins/__init__.py

@@ -10,3 +10,4 @@
 from .terminator import Terminator
 from .boat_marker import BoatMarker
 from .timestamped_geo_json import TimestampedGeoJson
+from .heat_map import HeatMap

folium/plugins/heat_map.py

@@ -0,0 +1,79 @@
+# -*- coding: utf-8 -*-
+"""
+Heat map
+--------
+
+Create a HeatMap layer
+"""
+import json
+from jinja2 import Template
+
+from folium.element import JavascriptLink, Figure
+from folium.map import TileLayer
+
+class HeatMap(TileLayer):
+    def __init__(self, data, name=None,
+                 min_opacity = .5, max_zoom=18, max_val=1.,
+                 radius=25, blur=15, gradient=None,
+                 overlay = True):
+        """Create a Heatmap layer
+
+        Parameters
+        ----------
+        data : list of points of the form [lat, lng, weight]
+            The point you want to plot.
+        name : str
+            The name of the layer that will be created.
+        min_opacity  : default 1.
+            The minimum opacity the heat will start at.
+        max_zoom : default 18
+            Zoom level where the points reach maximum intensity (as intensity scales with zoom),
+            equals maxZoom of the map by default
+        max_val : float, default 1.
+            Maximum point intensity
+        radius : int, default 25
+            Radius of each "point" of the heatmap
+        blur : int, default 15
+            Amount of blur
+        gradient : dict, default None
+            Color gradient config. e.g. {0.4: 'blue', 0.65: 'lime', 1: 'red'}
+        """
+        super(TileLayer, self).__init__()
+        self._name = 'HeatMap'
+        self.tile_name = name if name is not None else self.get_name()
+
+        self.data= data
+        self.min_opacity = min_opacity
+        self.max_zoom = max_zoom
+        self.max_val = max_val
+        self.radius = radius
+        self.blur = blur
+        self.gradient = json.dumps(gradient, sort_keys=True) if gradient is not None else "null"
+        self.overlay = overlay
+
+        self._template = Template(u"""
+        {% macro script(this, kwargs) %}
+            var {{this.get_name()}} = L.heatLayer(
+                {{this.data}},
+                {
+                    minOpacity: {{this.min_opacity}},
+                    maxZoom: {{this.max_zoom}},
+                    max: {{this.max_val}},
+                    radius: {{this.radius}},
+                    blur: {{this.blur}},
+                    gradient: {{this.gradient}}
+                    })
+                .addTo({{this._parent.get_name()}});
+        {% endmacro %}
+        """)
+
+    def render(self, **kwargs):
+        super(TileLayer, self).render()
+
+        figure = self.get_root()
+        assert isinstance(figure,Figure), ("You cannot render this Element "
+            "if it's not in a Figure.")
+
+        figure.header.add_children(\
+            JavascriptLink("https://leaflet.github.io/Leaflet.heat/dist/leaflet-heat.js"),
+            name='leaflet-heat.js')

tests/test_plugins.py

@@ -134,3 +134,9 @@ def test_timestamped_geo_json(self):
         mape = folium.Map([47, 3], zoom_start=1)
         mape.add_children(plugins.TimestampedGeoJson(data))
         mape._repr_html_()
+
+    def test_heat_map(self):
+        data = (np.random.normal(size=(100,2))*np.array([[1,1]])+np.array([[48,5]])).tolist()
+        mapa = folium.Map([48., 5.], tiles='stamentoner', zoom_start=6)
+        mapa.add_children(plugins.HeatMap(data))
+        mapa._repr_html_()