anchor.diff:                      }
                   ]
               }
  +
  +--------
  +
  +Alternative
  +* completly flat structure.
  +* no prior aggregation leaves room for transposition tables approach
  +* again, every field must be requested in fields request parameter
  +
  +                "items" : [
  +                    {
  +                        "location" : [13.37788, 52.5337],
  +                        "meteoGroupStationId" : "abcd1234ef5678",
  +                        "stationName" : "Berlin Dahlem",
  +                        "stationLocation" : [13.36612, 52.1234],
  +                        "stationTimeZoneName" : "Europe/Berlin"
  +                        "observedFromUtc": "2016-10-13T11:00:00Z",
  +                        "observedUntilUtc": "2016-10-13T12:00:00Z",
  +                        "observedPeriod" : "PT1H",
  +                        "sunshineDurationInMinutes": 15,
  +                        "windGustInKnots" : 20,
  +                    },
  +                    {
  +                        "location" : [13.37788, 52.5337],
  +                        "meteoGroupStationId" : "abcd1234ef5678",
  +                        "stationName" : "Berlin Dahlem",
  +                        "stationLocation" : [13.36612, 52.1234],
  +                        "stationTimeZoneName" : "Europe/Berlin"
  +                        "observedFromUtc": "2016-10-13T06:00:00Z",
  +                        "observedUntilUtc": "2016-10-13T18:00:00Z",
  +                        "observedPeriod" : "PT12H",
  +                        "sunshineDurationInMinutes": 123,
  +                        "windGustInKnots" : 20,
  +                    },
  +                    {
  +                        "location" : [13.37788, 52.5337],
  +                        "meteoGroupStationId" : "abcd1234ef5678",
  +                        "stationName" : "Berlin Dahlem",
  +                        "stationLocation" : [13.36612, 52.1234],
  +                        "stationTimeZoneName" : "Europe/Berlin"
  +                        "observedFromUtc": "2016-10-13T12:00:00Z",
  +                        "observedUntilUtc": "2016-10-13T12:00:00Z",
  +                        "observedPeriod" : "PT0S",
  +                        "airTemperatureInCelsius": 29.6,
  +                        "windSpeedInKnots" : 14
  +                    }
  +
  +
  +-----------------------------------
  +
  +
   
   # Group Forecast
   
  
positive.code: For any requested location a relevant station is computed.
  To the relevant station, the distance and available parameters are taken into concern.
  
  + Parameters
      + locatedAt: `13.37788,52.5337` (string, required) - longitude,latitude; can occur multiple times for multiple stations
      + locatedAt: `joionluqqFvwqmo629nC` (string, optional) - compressed list of station locations, using Microsoft Point Compression Algorithm, is efficient for up to 400 locations
      + fields: `sunshineDurationInMinutes,airTemperatureInCelsius` (string, required) - comma separated list of parameters to be contained inside response
      + observedFromUtc: `2016-10-13T11:00:00Z` (string, optional)
      + observedUntilUtc: `2016-10-13T15:00:00Z` (string, optional)
      + observedFromLocalTime: `2016-10-13T11:00:00Z` (string, optional)
      + observedUntilLocalTime: `2016-10-13T15:00:00Z` (string, optional)
      + observedPeriod: `PT0S,PT1H,PT12H` (string, required) - comma separated list of periods to be retrieved. use iso8601 time duration notation. PT0S refers to observations at a moment in time. PT1H applies one hour aggregation.
  
  + Response 200 (application/json)
  
negative.code: 
                  "items" : [
                      {
                          "location" : [13.37788, 52.5337],
                          "relevantStation" : {
                              "meteoGroupStationId" : "abcd1234ef5678",
                              "stationName" : "Berlin Dahlem",
                              "location" : [13.36612, 52.1234],
                              "timeZoneName" : "Europe/Berlin"
                          },
                          "observation" : [
                              {
                                  "observedFrom": "2016-10-13T11:00:00Z",
                                  "observedUntil": "2016-10-13T12:00:00Z",
                                  "observedPeriod" : "PT1H",
                                  "sunshineDurationInMinutes": 15,
                                  "windGustInKnots" : 20,
                              },
                              {
                                  "observedFrom": "2016-10-13T06:00:00Z",
                                  "observedUntil": "2016-10-13T18:00:00Z",
                                  "observedPeriod" : "PT12H",
                                  "sunshineDurationInMinutes": 123,
                                  "windGustInKnots" : 20,
                              },
                              {
                                  "observedFrom": "2016-10-13T12:00:00Z",
                                  "observedUntil": "2016-10-13T12:00:00Z",
                                  "observedPeriod" : "PT0S",
                                  "airTemperatureInCelsius": 29.6,
                                  "windSpeedInKnots" : 14
  