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One of the most important properties of Delft-FEWS as a forecasting system is its ability to efficiently deal with large volumes of dynamic data. Dynamic data covers mainly time series data in various formats (scalar- 0D, vector - 1D, longitudinal profile - 1D and 2D, grid - 2D and 3D, and polygon data - 2D). Dynamic data also includes the management of model states produced by the system. As Delft-FEWS is not only used as operational forecasting system, but also as a system to run climate scenarios, the length of each time series can be up up to 2,000,000,000 time steps. A thorough understanding of how Delft-FEWS handles dynamic data is fundamental to correctly configuring an operational system. Specific optimisations are available for each type of dynamic data. This chapter introduces the concept of a "Time Series Set". A Time Series Set is used to retrieve data from and submit data to the database.

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In an operational system, DELFTDelft-FEWS incrementally imports observed data as it becomes available from external systems. These data should be imported as External Historical time series. When data marked as external historical is presented to the system with exactly the same values and covering the same period as data for that location/parameter already available in the database, then it will be ignored (i.e. not imported). Only new data are imported and stored. If data for a given period is already available but is changed (manual edit or update), the new values will be added to the database. For each item of data added to the database, a time stamp is included to specify when the data was made available to the system.

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Time Series Sets

Any module in DELFTDelft-FEWS that requires data from the database, or produces data that must be stored in the database, does so through the use of a complex data type referred to as the Time Series Set. A time series set can be compared to a query that is run against the database. It contains all the keys to uniquely identify the set of data to be retrieved (for more information on key attributes, see Key attributes).

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The relative view period defines the span of time for which data is to be retrieved. This span of time is referenced to the start time of the forecast run (T0) the time series set is used in. If the time series set is not used in a forecast run (e.g. in the displays), then the reference is to the DELFTDelft-FEWS system time.

Parameters

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•         timeZone defines the timeZone, this is only relevant for units of a day or larger.

readWriteMode

externalForecastSearchTimeStep

Since 2024.01. Only time series with an external forecast time that match this time step are visible while searching, e.g. an externalForecast timeseries that has a  externalForecastTime of 18:00 in the GMT timeZone.

All timestep attributes are available, probably most relevant options are;

•        id  Id of the time step. You can reference time steps defined in the regionConfig/timeSteps.xml.    
•        times Defines the time step by a list of times without dates, e.g. "10:00 23:00"
•         timeZone defines the timeZone, this is only relevant for units of a day or larger.

<timeSeriesSet>
	<moduleInstanceId>ImportACCESS-GE</moduleInstanceId>
	<valueType>grid</valueType>
	<parameterId>P.nwp.fcst</parameterId>
	<locationId>ACCESS-GE_grid</locationId>
	<timeSeriesType>external forecasting</timeSeriesType>
	<timeStep unit="hour"/>
	<relativeForecastPeriod unit="hour" start="0" end="246"/>
	<externalForecastSearchTimeStep times="18:00" timeZone="GMT"/>
	<readWriteMode>read complete forecast</readWriteMode>
</timeSeriesSet>

readWriteMode

The readWriteMode definition is mainly used in the definition of filters to be applied in the time series display when used in edit mode. This element is an enumeration ofThe readWriteMode definition is mainly used in the definition of filters to be applied in the time series display when used in edit mode. This element is an enumeration of;

•         read only implies the data cannot be edited.

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• Manually corrected (not completed) imported values will not be rollbacked rolled back when the value is reimported.
• Values added in the period after T0 in an external historical timeserietimeseries, WILL be overwritten by imported values.
• All other modules that generate the timeserie timeseries (such as a transformation)  WILL WILL overwrite manually edited data.

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