anchor.diff:  https://lightning.weather.mg/weighted?&temporalResolution=PT15M&spatialResolution=0.5&locationWithin=[-10,80],[10,5]&occurredFrom=2017-01-05T12:19:14Z
   https://lightning.weather.mg/weighted?&temporalResolution=PT15M&spatialResolution=0.5&locationWithin=[-10,80],[10,5]
   
  +##### Limitation
  +Since AWS API Gatewey has maximum response time 30 seconds and a Lambda instance can allocate no more than 1.5Gb RAM it is impossible to process a really huge amount of lightning events. Therefore at most 200 000 first lightnings are being taken into account.
  +
   ### Observed weighted lightning for a given boundingBox, time period, weighted by time span and spatial resolution
   
   This resource provides data from existing lightning observation providers.
  
positive.code: 
  # Group Lightning
  
  ## Retrieve lightning observation [?provider={provider1,provider2}&locationWithin={lonTopLeft,latTopLeft,lonBottomRight,latBottomRight}&occurredFrom={startTime}&occurredUntil={endTime}]
  ## Retrieve lightning observation [?provider={provider1,provider2}&locationWithin={lonTopLeft,latTopLeft,lonBottomRight,latBottomRight}&occurredFrom={startTime}]
  
  #### Example
  https://lightning.weather.mg/search?provider=NOWCAST&locationWithin=[-10,80],[10,5]&occurredFrom=2017-01-05T12:21:14Z&occurredUntil=2017-01-05T12:21:15Z
  https://lightning.weather.mg/search?provider=NOWCAST&locationWithin=[-10,80],[10,5]&occurredFrom=2017-01-05T12:21:14Z
  https://lightning.weather.mg/search?provider=NOWCAST&locationWithin=[-10,80],[10,5]
  
  ##### Limitation
  AWS Lambda service response can have size < 6MB
  If locationWithin is worldwide [-180, 90][180, -90] and occurrence ~3 days
  
  ### Observed lightning for a given boundingBox and time period
  
negative.code:     + occurredUntil: `2017-01-05T12:21:15Z` (end time range, optional)
          - time range period for lightning observation.
  
      + provider: `ENGLN,NOWCAST` (string, required)
          - lightning providers.
  
      + startPosition: `60000` (not negative integer, optional)
          - Is used for pagination. It is recommnded to set it as multiple of 30 000.
  
  
  + Response 200 (application/json)
  