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Required element defining the maximum radius in which the transformation searches the closest location/grid cell. The unit is meters. But please 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 pre-sort the input points in a grid the earth's curved surface should be transformed to a flat two-dimensional surface. When the input geometry is not in meters calculation of distances will be very slow and a search all is required when there is no exact match. When there is no region/country specific coordinate system available choose a utm zone that best fits with your output region. http://en.wikipedia.org/wiki/File:Utm-zones.jpg
. eg. UTM55S for Victoria state in Australia. Only use zone number and N for northern hemisphere and S for southern hemisphere.
InverseDistancePower
Required element to define the InverseDistanceOptionPower to which the inverse distance will be raised to calculate the weight factor of the input location/grid cell
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