schema: 

keywords: 
transformation, spatial interpolation, i= nverse distance 
This transformation function calculates the output based on the wei= ghted average of the closest input locations/grid cells. The weight of each= input location/grid cell will be calculated by the inverse distance of eac= h location.
This transformation can handle four types of input:
The output can be a:
If the time series is not a scalar time series the centre of the grid ce= ll will be used when trying to find the closest input location/gr= id cell.
When a longitudinal profile is used the profile is considered to be a sc= attered grid.
The configurator has the possibility to configure a minimum and maximum = value for the output. If the output exceeds the minimum or maximum value th= e output is truncated to that value.
It is also possible to maximize the search radius in which the transform= ation searches for the closest input location/grid cell. This can be done b= y setting the searchRadius in the configuration.
The weight of each input value in the output is computed by the inverse = distance from the input location/grid cell to the output location/grid cell= , using the formula:
where D is the distance between the input location/grid cell and the out= put location/grid cell, P is the configured inverseDistancePower and w is t= he weight.
The power to which the inverse distance is raised in this calculation ca= n be configured. It is also possible to configure the maximum total number = of input values which are used to calculate the output. First the transform= ation will try to find the closest input locations/grid cells which should = be used in the calculation. If one or more values in the input values of th= ese time series are missing values, the transformation will not search for = the next closest locations/grid cells but will ignore these values in the c= alculation.
In this function one input time series and one output time series must b= e identified.
A basic configuration of the function is described below. This describes= the main elements and attributes required and provides an example configur= ation.
inputVariable
Required element defining the identifier of t=
he input time series with input values. This Id must reference a valid inpu=
t time series.
outputVariable
Required element defining the identifier of =
the output time series with output values. This Id must reference a valid o=
utput time series.
minimumValue
Optional element defining the minimum value of the output time series. I= f the output value is lower than the configured minimum value the output va= lue will be equal to the configured minimum value.
maximumValue
Optional element defining the maximum value of the output time series. I= f the output value is higher than the configured maximum value the out= put value will be equal to the configured maximum value.
searchRadius
Required element defining the maximum radius in which the transform= ation searches the closest location/grid cell. The unit is meters. But plea= se note, before 2012.02 it was by accident in kilometers for WGS84.
distanceGeoDatum
Geo datum used to calculate the distances in meters between the points. = To calculate distances efficiently and to presort the input points in a gr= id the earth's curved surface should be transformed to a flat twodimension= al surface. When the input geometry is not in meters calculation of distanc= es will be very slow and a search all is required when there is no exact ma= tch. When there is no region/country specific coordinate system available c= hoose a utm zone that best fits with your output region. http://en.wikipedia.org/wiki/File:Utmzones.jpg. eg. UTM55S for= Victoria state in Australia. Only use zone number and N for northern hemis= phere and S for southern hemisphere.
InverseDistancePower
Required element to define the InverseDistanceOptionPower to which the i= nverse distance will be raised to calculate the weight factor of the input = location/grid cell
numberOfpoints
Required elemet to defie the maximum number of points/grid cells wh= ich will be used to calculate the output.
excludePointOfOrigin
Optinal field, default value is false. If it is set to true, the po= int of origin in the inversedistance spatial interpolation transformation = will be excluded from the calculation.
Example
<inte= rpolationSpatial> =09<inverseDistance> =09=09<inputVariable> =09=09=09<variableId>input</variableId> =09=09</inputVariable> =09=09<minimumValue>0</minimumValue> =09=09<maximumValue>10000</maximumValue> =09=09<searchRadius>100000</searchRadius> =09=09<inverseDistancePower>2</inverseDistancePower> =09=09<numberOfPoints>3</numberOfPoints> =09=09<outputVariable> =09=09=09<variableId>output</variableId> =09=09</outputVariable> =09</inverseDistance> </interpolationSpatial>=20
None reported.