22 forecastLengthEstimator

Function:	Sets the forecast length

Module Name:	ForecastLengthEstimator
Where to Use?	In a workflow
Why to Use?	To set the length of a forecast based on (external) timeseries
Description:	The forecastLengthEstimator is a module that can be used at the start of a workflow the set the length of the operations in the other modules in that workflow.
Preconditions:	the endoverrulable attribute in the relative view period in the time series sets must be set to true in all modules you want to apply the forecast length to
Outcome(s):
Scheendump(s):	link to attached screendump(s) for displays only
Remark(s):
Available since:	DelftFEWS200803

Overview

The forecastLengthEstimator is a module that can be used at the start of a workflow to set the length of the operations in the other modules in that workflow. As most models cannot handle gaps in the input data, this option can be useful if you want to run a hydrological model only with the data available and thus avoid e.g. extrapolating the meteorological forecast data.

Configuration

A configuration example of the forecast length estimator is given below:

<?xml version="1.0" encoding="UTF-8"?>
<forecastLengthEstimator xmlns="http://www.wldelft.nl/fews" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.wldelft.nl/fews http://fews.wldelft.nl/schemas/version1.0/forecastLengthEstimator.xsd">
	<externalForecastTimeSeries>
			<moduleInstanceId>ImportCOSMO2</moduleInstanceId>
			<valueType>grid</valueType>
			<parameterId>P.fg</parameterId>
			<locationId>COSMO2</locationId>
			<timeSeriesType>external forecasting</timeSeriesType>
			<timeStep unit="hour" multiplier="1"/>
			<relativeViewPeriod unit="hour" start="0" end="30"/>
			<readWriteMode>read only</readWriteMode>
	</externalForecastTimeSeries>
	<minForecastLength multiplier="3" unit="hour"/>
	<maxForecastLength multiplier="30" unit="hour"/>
</forecastLengthEstimator>

The forecast length is defined by the length of the external forecast time series ImportCOSMO2. You can define a mimimum and / or maximum forecast length (minForcastLength / maxForecastLength). If the actual forecast length of the external forecast looked at is shorter than the minimum forecast length (in the example less than 3 hours) the forecast length is set to this minimum forecast length. If the actual forecast length is longer than the maximum forecast length (in the example longer than 30 hours) the forecast length is set to this maximum forecast length.

The logging will provide you with the information which forecast length was used in the run, see example below

24:58,097 INFO - Workflow.run - Workflow.ActivityStarted: Workflow 'HBV_FlowForecast_ECMWF'
24:58,097 INFO - WorkflowPluginActivity.run - Started Activity ForecastLength_ECMWF
24:58,238 INFO - ForecastLengthEstimator.updateForecastLength - ForecastLengthEstimator.Info: Established Forecast Length as 234 hours

Note that the endoverrulable attribute in the relativ view period in timeseriessets must be set to true in all subsequent modules in which you want to use the actual forecast length.

Sample input and output

Sample input and output

Error and warning messages

Description of errors and warnings that may be generated

Error:	Error message
Action:	Action to fix

Known issues

Describe all known issues and unexpected behaviour

Technical reference

Entry in moduleDescriptors:	nl.wldelft.fews.system.plugin.forecastlength.ForecastLengthEstimator
Link to schema:	http://fews.wldelft.nl/schemas/version1.0/forecastLengthEstimator.xsd

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