Fix #341: Added highlight function for Choropleth

CHANGES.txt

@@ -8,6 +8,7 @@
 - Added options to LayerControl (qingkaikong #473)
 - Added text path (talespaiva #451 and #474)
 - Update font-awesome to 4.6.3 (ocefpaf #478)
+- Add highlight function to GeoJSON, and Chrorpleth (JoshuaCano #341)
 
 Bug Fixes
 

examples/GeoJSON_and_choropleth.ipynb

@@ -783,6 +783,37 @@
     "m"
    ]
   },
+{
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "You can also enable the highlight function, to enable highlight functionality when you hover over each area."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "state_geo = r'us-states.json'\n",
+    "state_unemployment = r'US_Unemployment_Oct2012.csv'\n",
+    "\n",
+    "state_data = pd.read_csv(state_unemployment)\n",
+    "\n",
+    "#Let Folium determine the scale\n",
+    "states = folium.Map(location=[48, -102], zoom_start=3)\n",
+    "states.choropleth(geo_path=state_geo, data=state_data,\n",
+    "                columns=['State', 'Unemployment'],\n",
+    "                key_on='feature.id',\n",
+    "                fill_color='YlGn', fill_opacity=0.7, line_opacity=0.2,\n",
+    "                legend_name='Unemployment Rate (%)', highlight=True)\n",
+    "\n",
+    "states"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},

examples/folium_examples.ipynb

@@ -2,7 +2,7 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -23,7 +23,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -50,7 +50,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -77,7 +77,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -106,7 +106,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -137,7 +137,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -165,10 +165,11 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
+<<<<<<< HEAD
    "outputs": [
     {
      "data": {
@@ -194,7 +195,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 8,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -229,7 +230,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -322,7 +323,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 10,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -367,7 +368,31 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": null,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "state_geo = r'us-states.json'\n",
+    "state_unemployment = r'US_Unemployment_Oct2012.csv'\n",
+    "\n",
+    "state_data = pd.read_csv(state_unemployment)\n",
+    "\n",
+    "#Enable Highlighting function, to allow hover highlight function\n",
+    "states = folium.Map(location=[48, -102], zoom_start=3)\n",
+    "states.choropleth(geo_path=state_geo, data=state_data,\n",
+    "                columns=['State', 'Unemployment'],\n",
+    "                key_on='feature.id',\n",
+    "                fill_color='YlGn', fill_opacity=0.7, line_opacity=0.2,\n",
+    "                legend_name='Unemployment Rate (%)', highlight=True)\n",
+    "\n",
+    "states"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -394,13 +419,13 @@
     "                 key_on='feature.id',\n",
     "                 fill_color='BuPu', fill_opacity=0.7, line_opacity=0.5,\n",
     "                 legend_name='Unemployment Rate (%)',\n",
-    "                 reset=True)\n",
+    "                 reset=True, highli)\n",
     "states2"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 12,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -453,7 +478,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 13,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },
@@ -497,7 +522,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": null,
    "metadata": {
     "collapsed": false
    },

folium/features.py

@@ -299,7 +299,8 @@ class GeoJson(Layer):
     >>> GeoJson(geojson, style_function=style_function)
     """
     def __init__(self, data, style_function=None, name=None,
-                 overlay=True, control=True, smooth_factor=None):
+                 overlay=True, control=True, smooth_factor=None,
+                 highlight_function=None):
         super(GeoJson, self).__init__(name=name, overlay=overlay,
                                       control=control)
         self._name = 'GeoJson'
@@ -332,19 +333,55 @@ def __init__(self, data, style_function=None, name=None,
 
         if style_function is None:
             def style_function(x):
-                return {}
+                return {} 
+
         self.style_function = style_function
 
+        self.highlight = highlight_function is not None
+
+        if highlight_function is None:
+            def highlight_function(x):
+                return {} 
+
+        self.highlight_function = highlight_function
+
         self.smooth_factor = smooth_factor
 
         self._template = Template(u"""
             {% macro script(this, kwargs) %}
+
+            {% if this.highlight %}
+                {{this.get_name()}}_onEachFeature = function onEachFeature(feature, layer) {
+                    layer.on({
+                        mouseout: function(e) {
+                            e.target.setStyle(e.target.feature.properties.style);},
+                        mouseover: function(e) {
+                            e.target.setStyle(e.target.feature.properties.highlight);},
+                        click: function(e) {
+                            {{this._parent.get_name()}}.fitBounds(e.target.getBounds());}
+                        });
+                };
+            {% endif %}
+
                 var {{this.get_name()}} = L.geoJson(
                     {% if this.embed %}{{this.style_data()}}{% else %}"{{this.data}}"{% endif %}
-                    {% if this.smooth_factor is not none %}
-                        , {smoothFactor:{{this.smooth_factor}}}
-                    {% endif %}).addTo({{this._parent.get_name()}});
+                    {% if this.smooth_factor is not none or this.highlight %}
+                        , {
+                        {% if this.smooth_factor is not none  %}
+                            smoothFactor:{{this.smooth_factor}}
+                        {% endif %}
+
+                        {% if this.highlight %}
+                            {% if this.smooth_factor is not none  %}
+                            ,
+                            {% endif %}
+                            onEachFeature: {{this.get_name()}}_onEachFeature
+                        {% endif %}
+                        }
+                    {% endif %}
+                    ).addTo({{this._parent.get_name()}});
                 {{this.get_name()}}.setStyle(function(feature) {return feature.properties.style;});
+
             {% endmacro %}
             """)  # noqa
 
@@ -363,6 +400,7 @@ def style_data(self):
 
         for feature in self.data['features']:
             feature.setdefault('properties', {}).setdefault('style', {}).update(self.style_function(feature))  # noqa
+            feature.setdefault('properties', {}).setdefault('highlight', {}).update(self.highlight_function(feature))  # noqa
         return json.dumps(self.data, sort_keys=True)
 
     def _get_self_bounds(self):

folium/folium.py

@@ -22,15 +22,13 @@
                        ClickForMarker, TopoJson, PolyLine, MultiPolyLine,
                        )
 
-
 def initialize_notebook():
     """Initialize the IPython notebook display elements."""
     warnings.warn("%s is deprecated and no longer required." %
                   ("initialize_notebook",),
                   FutureWarning, stacklevel=2)
     pass
 
-
 class Map(LegacyMap):
     """Create a Map with Folium and Leaflet.js
 
@@ -510,7 +508,8 @@ def choropleth(self, geo_path=None, geo_str=None, data_out='data.json',
                    data=None, columns=None, key_on=None, threshold_scale=None,
                    fill_color='blue', fill_opacity=0.6, line_color='black',
                    line_weight=1, line_opacity=1, legend_name="",
-                   topojson=None, reset=False, smooth_factor=None):
+                   topojson=None, reset=False, smooth_factor=None, 
+                   highlight=None):
         """
         Apply a GeoJSON overlay to the map.
 
@@ -582,6 +581,8 @@ def choropleth(self, geo_path=None, geo_str=None, data_out='data.json',
             How much to simplify the polyline on each zoom level. More means
             better performance and smoother look, and less means more accurate
             representation. Leaflet defaults to 1.0.
+        highlight: boolean, default False
+            Enable highlight functionality when hovering over a GeoJSON area.
 
         Returns
         -------
@@ -598,6 +599,12 @@ def choropleth(self, geo_path=None, geo_str=None, data_out='data.json',
         ...              threshold_scale=[0, 20, 30, 40, 50, 60])
         >>> m.choropleth(geo_path='countries.json',
         ...              topojson='objects.countries')
+        >>> m.choropleth(geo_path='geo.json', data=df,
+        ...              columns=['Data 1', 'Data 2'],
+        ...              key_on='feature.properties.myvalue',
+        ...              fill_color='PuBu',
+        ...              threshold_scale=[0, 20, 30, 40, 50, 60],
+        ...              highlight=True)
 
         """
         if threshold_scale and len(threshold_scale) > 6:
@@ -679,6 +686,13 @@ def style_function(x):
                 "fillColor": color_scale_fun(x)
             }
 
+
+        def highlight_function(x):
+            return {
+                "weight": line_weight + 2,
+                "fillOpacity": fill_opacity + .2
+            }
+
         if topojson:
             geo_json = TopoJson(
                 geo_data,
@@ -689,7 +703,8 @@ def style_function(x):
             geo_json = GeoJson(
                 geo_data,
                 style_function=style_function,
-                smooth_factor=smooth_factor)
+                smooth_factor=smooth_factor,
+                highlight_function=highlight_function if highlight else None)
 
         self.add_child(geo_json)