Transformation - InterpolationSpatial Inverse distance
schema: | |
keywords: | transformation, spatial interpolation, inverse distance |
Description and usage
For each input polygon this transformation copies the value of the input polygon to all output points that are inside the input polygon. If an output point is not contained in any input polygon, then the output is a missing value.”
Input/Output time series
In this function one input time series and one output time series must be identified.
- inputVariable: a time series with input values. Thismust be a scalar time series with polygons.
- outputVariable: a time series in which the output will be stored. This can be a time series with a regular/irregular grid.
Configuration
A basic configuration of the function is described below. This describes the main elements and attributes required and provides an example configuration.
inputVariable
Required element defining the identifier of the input time series with input values. This Id must reference a valid input time series.
outputVariable
Required element defining the identifier of the output time series with output values. This Id must reference a valid output time series.
minimumValue
Optional element defining the minimum value of the output time series. If the output value is lower than the configured minimum value the output value will be equal to the configured minimum value.
maximumValue
Optional element defining the maximum value of the input time series. If the output value is higher than the configured maximum value the output value will be equal to the configured maximum value.
searchRadius
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
numberOfpoints
Required elemet to defie the maximum number of points/grid cells which will be used to calculate the output.
Example
<transformation id="Polygon2Grid">
<interpolationSpatial>
<containingPolygon>
<inputVariable>
<variableId>input_polygon</variableId>
</inputVariable>
<outputVariable>
<variableId>output_grid</variableId>
</outputVariable>
</containingPolygon>
</interpolationSpatial>
</transformation>
Common issues
None reported.
