clarify documentation, close Leaflet#36

README.md

@@ -15,7 +15,11 @@ additionally clustering points into a grid for performance.
 ## Basic Usage
 
 ```js
-var heat = L.heatLayer(latlngs, {radius: 25}).addTo(map);
+var heat = L.heatLayer([
+	[50.5, 30.5, 0.2], // lat, lng, intensity
+	[50.6, 30.4, 0.5],
+	...
+], {radius: 25}).addTo(map);
 ```
 
 To include the plugin, just use `leaflet-heat.js` from the `dist` folder:
@@ -33,7 +37,7 @@ To build the dist files run:
 
 #### L.heatLayer(latlngs, options)
 
-Constructs a heatmap layer given an array of `LatLng` points and an object with the following options:
+Constructs a heatmap layer given an array of points and an object with the following options:
 - **minOpacity** - the minimum opacity the heat will start at
 - **maxZoom** - zoom level where the points reach maximum intensity (as intensity scales with zoom),
   equals `maxZoom` of the map by default
@@ -42,7 +46,12 @@ Constructs a heatmap layer given an array of `LatLng` points and an object with
 - **blur** - amount of blur, `15` by default
 - **gradient** - color gradient config, e.g. `{0.4: 'blue', 0.65: 'lime', 1: 'red'}`
 
+Each point in the input array can be either an array like `[50.5, 30.5, 0.5]`,
+or a [Leaflet LatLng object](http://leafletjs.com/reference.html#latlng).
+
 Optional third argument in each `LatLng` point (`altitude`) represents point intensity.
+Unless `max` option is specified, intensity should range between `0.0` and `1.0`.
+
 
 #### Methods