anchor.diff:    @map.on 'popupclose', (e) -> setWindDate(new Date)
   
     # When requesting sessions, convert the timestamp from milliseconds to seconds
  -  $.get '/sessions', ({last_updated_at: (lastUpdatedAt / 1000).toFixed()} if lastUpdatedAt?), (sessions) ->
  +  $.get '/sessions', ({last_updated_at: (lastUpdatedAt / 1000).toFixed()} if lastUpdatedAt?), (sessions) =>
       for session in sessions
         markers.push(initializeMarkerForSession(session))
   
  
positive.code:   $('#wind-date').text(formatDate(date))
  
  @addHeatLayer = (heatLayer=null) ->
    $.get '/sessions', (sessions) ->
      heats = []
      for session in sessions
        heats.push sessionToHeat(session)
  
negative.code:       heatLayer = L.heatLayer(heats, {radius: 20})
        addLayerToMap(heatLayer)
  
      @dataPollPromise = setTimeout((-> addHeatLayer(heatLayer)), dataPollDelay)
  
  @sessionToHeat = (session) ->
    [session.spot.location.lat, session.spot.location.lng, session.number_of_jumps]
  