Information
Transformation: |
Weighted |
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Transformation Group: |
InterpolationSpatial |
Description: |
For each time step this transformation calculates the weighted average of the input variables. The weights are re-scaled so that the total weight becomes 1. If for a given time an input variable has a missing value, then for that time that input variable is ignored and the weights of the other input variables are re-scaled so that the total weight becomes 1. |
Hydrological Information
Purpose and use of Transformation: |
This transformation can for example be used to calculate the weighted average of the amount of rainfall of a number of locations in a catchment. |
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Background and Exceptions: |
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Input
One or more weighted input variables. Each input variable has a weight.
Options
minInputValuesRequired (optional)
This is the minimum number of input variables that should have a non-missing value for the calculation. If for a given time the number of input variables that have a non-missing value is less than this configured minimum, then for that time the output value will be a missing value. This can be used for example to avoid getting output values of calculations for which very few input variables are available, because such calculations would be inaccurate. If minInputValuesRequired is not specified, then it will be set to 1.
Output
Weighted average.
Configuration Example
<transformation id="interpolation spatial weighted"> <interpolationSpatial> <weighted> <weightedInputVariable> <inputVariable> <variableId>location1</variableId> </inputVariable> <weight>0.3</weight> </weightedInputVariable> <weightedInputVariable> <inputVariable> <variableId>location2</variableId> </inputVariable> <weight>0.2</weight> </weightedInputVariable> <weightedInputVariable> <inputVariable> <variableId>location3</variableId> </inputVariable> <weight>0.1</weight> </weightedInputVariable> <weightedInputVariable> <inputVariable> <variableId>location4</variableId> </inputVariable> <weight>0.4</weight> </weightedInputVariable> <minInputValuesRequired>2</minInputValuesRequired> <outputVariable> <variableId>average</variableId> </outputVariable> </weighted> </interpolationSpatial> </transformation>