anchor.diff:      + observedUntil: `2016-10-15T09:00:00Z` (string, optional) - ISO8601 timestamp notation, means incl. this timestamp; always provide a time offset, e.g. 'Z' for UTC; optional: a request may provide correct offset (so that server can convert to UTC).
       + observedPeriod: `PT0S,PT1H,PT3H,PT12H,PT24H` (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.
       + timeZone: `Europe/Paris` (string, optional) - Time zone refers to the IANA Time Zone Database (TZDB).
  +	+ gapFilling: 'true' () (string, optional) - additional parameter, added to the request with flag true enables to gapFill missing observations with forecasts from MOSI for particular parameters.
   
   ### Search for observation data for multiple given locations [GET]
   
  
positive.code: 
  Every endpoint may add one or more response parameters in the future.
  Clients should ignore unknown parameters, to avoid technical issues.
  
  
  # Group Observation
  
  
negative.code: The 'shipCourseText' returns one of the following values: "not moving", "NE", "E", "SE", "S", "SW", "W", "NW", "N", "unknown".
  The 'shipSpeedRangeInKnots' returns one of the following values: "0", "1-5", "6-10", "11-15", "16-20", "21-25", "26-30", "31-35", "36-40", ">40", "unknown".
  
  *Gap filling*
  
  GapFilling allows to gap fill missing observations with forecast data from MOSI for following parameters: 
  + airPressureAtSeaLevelInHectoPascal
  + airTemperatureInCelsius
  + airTemperatureInFahrenheit
  + airTemperatureInKelvin
  + dewPointTemperatureInCelsius
  + dewPointTemperatureInFahrenheit
  + dewPointTemperatureInKelvin
  + effectiveCloudCoverInOkta
  + relativeHumidityInPercent
  + totalCloudCoverInOkta
  + windDirectionInDegree
  + windSpeedInKilometerPerHour
  + windSpeedInMeterPerSecond
  + windSpeedInMilesPerHour 
  
  GapFilling is applied always when requested, regardless if any of observations are available.
  GapFilling is available only for PT0S period. 
  
  *Fields mapping*
  
  Common names of filed which can be included in all periods: meteoGroupStationId, meteoGroupStationName, stationLocation, stationTimeZoneName
  