Description
Set of rules to allow selection of lows from an input time series.
This transformation will select lows only if there is a defined gap in time between lows. If not they are considered to be of dependent and only the lowest low of the dependent sets will be returned.
Attributes
Requirements for definitions of peak selections using gaps to define independence are;
- An attribute "gapLengthInsec" must be defined. The value attribute defines the length of the minimum gap in seconds.
- An attribute "lowsBeforeT0" must be defined. The value attribute defines the maximum number of lows to consider before T0.
- An attribute "lowsAfterT0" must be defined. The value attribute defines the maximum number of lows to consider before T0.
- An attribute "totalNumberOfLows" must be defined. The value must be set to zero.
The following two attributes are optional:
- An attribute "skipJustBeforeT0" indicates how many lows to skip just before T0.
- An attribute "skipJustAfterT0" indicates how many lows to skip just after T0.
They default to 0.
Configuration example
SelectionLowsFunctionTest 1.00 default.xml
<transformation id="lows function test">
<selection>
<lows>
<inputVariable>
<timeSeriesSet>
<moduleInstanceId>SelectionLowsFunctionTest</moduleInstanceId>
<valueType>scalar</valueType>
<parameterId>H.tidal</parameterId>
<locationId>H-2010</locationId>
<timeSeriesType>external historical</timeSeriesType>
<timeStep unit="minute" multiplier="15"/>
<relativeViewPeriod unit="day" start="0" end="365"/>
<readWriteMode>editing visible to all future task runs</readWriteMode>
</timeSeriesSet>
</inputVariable>
<gapLengthInSec>2700</gapLengthInSec>
<lowsBeforeT0>0</lowsBeforeT0>
<lowsAfterT0>15</lowsAfterT0>
<totalNumberOfLows>0</totalNumberOfLows>
<skipJustBeforeT0>0</skipJustBeforeT0>
<skipJustAfterT0>5</skipJustAfterT0>
<outputVariable>
<timeSeriesSet>
<moduleInstanceId>SelectionLowsFunctionTest</moduleInstanceId>
<valueType>scalar</valueType>
<parameterId>H.updated</parameterId>
<locationId>H-2010</locationId>
<timeSeriesType>external historical</timeSeriesType>
<timeStep unit="nonequidistant"/>
<relativeViewPeriod unit="day" start="-5" end="15"/>
<readWriteMode>add originals</readWriteMode>
</timeSeriesSet>
</outputVariable>
</lows>
</selection>
</transformation>
In this example:
- The time between two local minima (lows) should be at least 2700 seconds or 45 minutes.
- Only the last three lows before T0 and the first four lows after T0 are considered.
- The last two lows just before T0 are skipped, leaving only the third last one.
- Similarly the first lows just after T0 are skipped, leaving the third and fourth ones.
