docs

README.md

@@ -109,7 +109,29 @@ The lower the number, the more power devoted to GeoLocation resulting in higher
 
   `@param {Integer} distanceFilter`
 
-  The minimum distance (measured in meters) a device must move horizontally before an update event is generated.  @see [Apple docs](https://developer.apple.com/library/ios/documentation/CoreLocation/Reference/CLLocationManager_Class/CLLocationManager/CLLocationManager.html#//apple_ref/occ/instp/CLLocationManager/distanceFilter)
+  The minimum distance (measured in meters) a device must move horizontally before an update event is generated.  @see [Apple docs](https://developer.apple.com/library/ios/documentation/CoreLocation/Reference/CLLocationManager_Class/CLLocationManager/CLLocationManager.html#//apple_ref/occ/instp/CLLocationManager/distanceFilter).  However, #distanceFilter is elastically auto-calculated by the plugin:  When speed increases, #distanceFilter increases;  when speed decreases, so does distanceFilter.
+
+  #distanceFilter is calculated as the square of speed-rounded-to-nearest-5 and adding configured #distanceFilter.
+
+    `(round(speed, 5))^2 + distanceFilter`
+
+  For example, at biking speed of 7.7 m/s with a configured distanceFilter of 30m:
+
+    => round(7.7, 5)^2 + 30
+    => (10)^2 + 30
+    => 100 + 30
+    => 130
+
+  A gps location will be recorded each time the device moves 130m.
+
+  At highway speed of 30 m/s with distanceFilter: 30,
+
+    => round(30, 5)^2 + 30
+    => (30)^2 + 30
+    => 900 + 30
+    => 930
+
+  A gps location will be recorded every 930m
 
   `@param {Integer} stationaryRadius (meters)`