anchor.diff:    @map.addLayer(layer)
     @activeLayer = layer
   
  -@addSelectedOverLayerToMap = ->
  +@addSelectedOverlayToMap = ->
     switch @selectedOverlay()
       when 'marker' then addMarkerLayer()
       when 'heat' then addHeatLayer()
  
positive.code:       heatLayer = L.heatLayer(heats, {radius: 20})
        addLayerToMap(heatLayer)
  
      setTimeout((-> addHeatLayer(heatLayer)), dataFetchDelay)
  
  @sessionToHeat = (session) ->
    [session.spot.location.lat, session.spot.location.lng, session.number_of_jumps]
  
negative.code: @dataPollDelay = 30000
  @activeLayer = null
  @map = null
  @dataPollPromise = null
  
  @initMap = (map) ->
    @map = map
    map.fitWorld()
    setWindDate(new Date)
    addSelectedOverlayToMap()
  
    $('#overlay-options input[name="overlay"]').change =>
      $('#overlay-options .overlay-option').toggleClass('selected')
      removeActiveLayerFromMap()
      addSelectedOverlayToMap()
  
  @setWindDate = (date) ->
    W.setTimestamp(date)
  