diff --git a/frontend/src/Main.elm b/frontend/src/Main.elm
index f999e5e..8d0056a 100644
--- a/frontend/src/Main.elm
+++ b/frontend/src/Main.elm
@@ -178,9 +178,9 @@ fetchTrack start duration = Http.get
 
 type Msg
   = MapScale Int
-  | PointerDown (Int, Int)
-  | PointerMove (Int, Int)
-  | PointerUp (Int, Int)
+  | MapDragStart (Int, Int)
+  | MapDrag (Int, Int)
+  | MapDragFinish (Int, Int)
   | TimeScale (Float)
   | Loaded (Result Http.Error (List Point))
   | NewUrlRequest
@@ -196,13 +196,13 @@ newModel msg model =
         MapScale y ->
             { model | zoom = incZoom model.zoom y }
 
-        PointerDown (x,y) ->
+        MapDragStart (x,y) ->
             { model | drag = Dragging (x,y) (x,y) }
 
-        PointerMove (x,y) ->
+        MapDrag (x,y) ->
             { model | drag = dragTo model.drag (x,y) }
 
-        PointerUp (x,y) ->
+        MapDragFinish (x,y) ->
             { model | drag = None,
                   centre = translatePixels model.centre (toZoom model.zoom) (dragDelta model.drag) }
 
@@ -214,7 +214,6 @@ newModel msg model =
                ,     duration = len
                }
 
-
         Loaded result ->
             case result of
                 Ok trk -> { model | track = Present trk }
@@ -395,9 +394,9 @@ canvas centre zoom width height model =
             ,style "left" (px -offsetX)
             ,style "top" (px -offsetY)
             ,style "lineHeight" (px 0)
-            ,Pointer.onUp (\e -> PointerUp (epos e))
-            ,Pointer.onMove (\e -> PointerMove (epos e))
-            ,Pointer.onDown (\e -> PointerDown (epos e)) ]
+            ,Pointer.onUp (\e -> MapDragFinish (epos e))
+            ,Pointer.onMove (\e -> MapDrag (epos e))
+            ,Pointer.onDown (\e -> MapDragStart (epos e)) ]
         (tv :: tiles xs ys zoom)
 
 portalWidth = 600