Aggregation InstantaneousToMean

InstantaneousToMean

Input

inputVariable

Options

allowMissingValues
includeFirstValueOfAggregationPeriodInCalculation

Output

outputVariable

Description

This transformations calculates the mean value of instantaneous values over a certain period. If the option allowMissingValues is true (this is the default behaviour), then a missing value is returned if one of the input values in the period is a missing value. If the option allowMissingValues is false, then a mean value is calculated if there are 1 or more non-missing values in the aggregation period, i.e. missing values are ignored in this case.

The transformation offers two different ways for calculating the mean value over a period. The default method (used by setting the includeFirstValueOfAggregationPeriodInCalculation option to true - this is the default behaviour) calculates the mean of the last n pairs, averages that, and stores it at the output time. An alternate method (similar to the MeanToMean aggregation) is enabled by setting the includeFirstValueOfAggregationPeriodInCalculation option to false) calculates the mean of all values that fit in the output interval, excluding the start time itself, and stores that at the output time.

In the table below an example of in and output using both methods is given:

includeFirstValueOfAggregationPeriodInCalculation:			false		true		false	true
allowMissingValues:			false		false		true	true
	Date/Time	Input Value	Output Value	Calculation	Value	Calculation	Value	Value
	01-01-2007 00:00	1
	01-01-2007 06:00	2
	01-01-2007 12:00	3
	01-01-2007 18:00	4
	02-01-2007 00:00	5	3,50	(2 + 3 + 4 + 5)/4	3	(((1+2)/2) + ((2+3)/2) + ((3+4)/2) + ((4+5)/2))/4	3,5	3
	02-01-2007 06:00	6
	02-01-2007 12:00	7
	02-01-2007 18:00	NaN
	03-01-2007 00:00	9	7,33	(6 + 7 + 9)/3	6	(((5+6)/2)+((6+7)/2))/2	NaN	NaN
	03-01-2007 06:00	10

Configuration example

	<transformation id="aggregation instantaneousToMean">
		<aggregation>
			<instantaneousToMean>
				<inputVariable>
					<timeSeriesSet>
						<moduleInstanceId>ImportTelemetry</moduleInstanceId>
						<valueType>scalar</valueType>
						<parameterId>H.obs</parameterId>
						<locationSetId>hydgauges</locationSetId>
						<timeSeriesType>external historical</timeSeriesType>
						<timeStep unit="minute" multiplier="15"/>
						<relativeViewPeriod unit="day" startOverrulable="true" start="-7" end="0"/>
						<readWriteMode>read only</readWriteMode>
						<delay unit="minute" multiplier="0"/>
					</timeSeriesSet>
				</inputVariable>
				<allowMissingValues>true</allowMissingValues>
				<outputVariable>
					<timeSeriesSet>
						<moduleInstanceId>Aggregate_Historic</moduleInstanceId>
						<valueType>scalar</valueType>
						<parameterId>instantaneousToMean</parameterId>
						<locationSetId>hydgauges</locationSetId>
						<timeSeriesType>external historical</timeSeriesType>
						<timeStep unit="hour" multiplier="1"/>
						<relativeViewPeriod unit="day" startOverrulable="true" start="-7" end="0"/>
						<readWriteMode>add originals</readWriteMode>
						<synchLevel>1</synchLevel>
					</timeSeriesSet>
				</outputVariable>
			</instantaneousToMean>
		</aggregation>
	</transformation>

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