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: NOWCAST and ENGLN.
  
positive.code:     + occurredUntil: `2017-01-05T12:21:15Z` (end time range, optional)
          - time range period for lightning observation.
  
  
      + provider: `ENGLN,NOWCAST' (string, required)
          - lightning providers.
  
  
  
  + Response 200 (application/json)
  
negative.code: 
  # Group Lightning
  
  ## Retrieve lightning observation [?provider={provider1,provider2}&locationWithin={lonTopLeft,latTopLeft,lonBottomRight,latBottomRight}&occurredFrom={startTime}&occurredUntil={endTime}&startPosition={startPosition}]
  ## 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&startPosition=30000
  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, it is about 30000 lightning events. If there are more than 30 000 results in storage which comply to the search criteria, they can be retrieved using pagination, by the use of startPosition parameter. In such case response contains Link header with the next startPosition offset.
  If locationWithin is worldwide [-180, 90][180, -90] and occurrence ~3 days
  
  
  ### Observed lightning for a given boundingBox and time period
  
  