Merge pull request #585 from JamesGardiner/fast-marker-cluster

Add Fast marker cluster to plugins

Author: ocefpaf

CHANGES.txt

@@ -3,10 +3,12 @@
 - Experimental support for a static png output (ocefpaf #634)
 - Added support for subdomains options in TileLayer (damselem #623)
 - Updated to leaflet 1.1.0 (ocefpaf #639)
+- Added `FastMarkerCluster` (James Gardiner #585 (proposed by @ruoyu0088))
 
 0.3.0
 ~~~~~
 
+- Added `FastMarkerCluster` (James Gardiner #585 (proposed by @ruoyu0088))
 - Added style option to 'Timestamped geojson' plugin (soymsk #627)
 - Switched to `leaflet 1.0.1` (juoceano #531 and ocefpaf #535)
 - Added `continuous_world`, `world_copy_jump`, and `no_wrap` options (ocefpaf #508)

examples/FastMarkerCluster.ipynb

@@ -7,6 +7,7 @@
 """
 
 from .boat_marker import BoatMarker
+from .fast_marker_cluster import FastMarkerCluster
 from .float_image import FloatImage
 from .fullscreen import Fullscreen
 from .heat_map import HeatMap
@@ -19,6 +20,7 @@
 
 __all__ = [
     'MarkerCluster',
+    'FastMarkerCluster',
     'ScrollZoomToggler',
     'Terminator',
     'BoatMarker',

folium/plugins/__init__.py

@@ -0,0 +1,74 @@
+# -*- coding: utf-8 -*-
+"""
+Marker Cluster plugin
+---------------------
+
+Creates a MarkerCluster plugin to add on a folium map.
+"""
+
+from jinja2 import Template
+
+from folium.plugins.marker_cluster import MarkerCluster
+
+
+class FastMarkerCluster(MarkerCluster):
+    """Add marker clusters to a map using in-browser rendering"""
+    def __init__(self, data, callback=None):
+        """Add marker clusters to a map using in-browser rendering.
+           Using FastMarkerCluster it is possible to render 000's of
+           points far quicker than the MarkerCluster class.
+
+           Be aware that the FastMarkerCluster class passes an empty
+           list to the parent class' __init__ method during initialisation.
+           This means that the add_child method is never called, and
+           no reference to any marker data are retained. Methods such
+           as get_bounds() are therefore not available when using it.
+
+        Parameters
+        ----------
+            data: list
+                List of list of shape [[], []]. Data points should be of
+                the form [[lat, lng]].
+
+            callback: string, default None
+                A string representation of a valid Javascript function
+                that will be passed a lat, lon coordinate pair. See the
+                FasterMarkerCluster for an example of a custom callback.
+
+        """
+        super(FastMarkerCluster, self).__init__([])
+        self._name = 'FastMarkerCluster'
+        self._data = data
+
+        if callback is None:
+            self._callback = ('var callback;\n' +
+                              'callback = function (row) {\n' +
+                              '\tvar icon, marker;\n' +
+                              '\t// Returns a L.marker object\n' +
+                              '\ticon = L.AwesomeMarkers.icon();\n' +
+                              '\tmarker = L.marker(new L.LatLng(row[0], ' +
+                              'row[1]));\n' +
+                              '\tmarker.setIcon(icon);\n' +
+                              '\treturn marker;\n' +
+                              '};')
+        else:
+            self._callback = "var callback = {};".format(callback)
+
+        self._template = Template(u"""
+            {% macro script(this, kwargs) %}
+            {{this._callback}}
+
+            (function(){
+                var data = {{this._data}};
+                var map = {{this._parent.get_name()}};
+                var cluster = L.markerClusterGroup();
+
+                for (var i = 0; i < data.length; i++) {
+                    var row = data[i];
+                    var marker = callback(row);
+                    marker.addTo(cluster);
+                }
+
+                cluster.addTo(map);
+            })();
+            {% endmacro %}""")

folium/plugins/fast_marker_cluster.py

@@ -0,0 +1,58 @@
+# -*- coding: utf-8 -*-
+"""
+Test FastMarkerCluster
+------------------
+"""
+
+from jinja2 import Template
+import numpy as np
+
+import folium
+from folium import plugins
+
+
+def test_fast_marker_cluster():
+    n = 100
+    np.random.seed(seed=26082009)
+    data = np.array([
+        np.random.uniform(low=35, high=60, size=n),   # Random latitudes.
+        np.random.uniform(low=-12, high=30, size=n),  # Random longitudes.
+        range(n),                                     # Popups.
+    ]).tolist()
+    m = folium.Map([45., 3.], zoom_start=4)
+    mc = plugins.FastMarkerCluster(data, callback=None)
+    m.add_child(mc)
+    m._repr_html_()
+
+    out = m._parent.render()
+
+    # We verify that imports
+    assert ('<script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet.'
+            'markercluster/1.0.0/leaflet.markercluster.js"></script>') in out
+    assert ('<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/'
+            'libs/leaflet.markercluster/1.0.0/MarkerCluster.css" />') in out
+    assert ('<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/'
+            'libs/leaflet.markercluster/1.0.0/MarkerCluster.Default.css" />'
+            ) in out
+
+    # Verify the script part is okay.
+    tmpl = Template("""
+        {% macro script(this, kwargs) %}
+        (function() {
+            var data = {{this._data}};
+            var map = {{this._parent.get_name()}};
+            var cluster = L.markerClusterGroup();
+            {{this._callback}}
+
+            for (var i = 0; i < data.length; i++) {
+                var row = data[i];
+                var marker = callback(row, popup='names');
+                marker.addTo(cluster);
+            }
+
+            cluster.addTo(map);
+        })();
+        {% endmacro %}
+    """)
+
+    assert ''.join(tmpl.render(this=mc).split()) in ''.join(out.split())