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96 lines
3.3 KiB
ReStructuredText
96 lines
3.3 KiB
ReStructuredText
INVERSE DISTANCE WEIGHTED
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=========================
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Description
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-----------
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It uses a point shapes data layer to provide values for “control points”.
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The points are irregularly distributed. A numeric attribute is chosen from the attribute table
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linked to the shapes data layer. The attribute data are the data values for the control points.
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Parameters
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----------
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- ``Points[Vector]``:
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Points shapes data layer for input.
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- ``Attribute[TableField]``:
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Identifying the attribute of the point shapes data layer that will provide the numeric
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data for the point objects
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- ``Target Grid[Selection]``:
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Grid data layer that will contain the interpolated data values as grid cell data.
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With “user defined” option (default) user must enter the target dimensions for the output
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grid data layer. Other options are:
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- ‘Grid Size’: the length of one side of the grid cells defining the grid data layer.
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- ‘Fit Extent’: if the box is checked, the west-east and north-south boundaries of the generated grid
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data layer will be defined by the minimum and maximum x and y coordinates for the data points.
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When the box is un-checked, the coordinate values entered for the ‘X-Extent’ and ‘Y-Extent’ parameters
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will be used to define the boundaries for the generated grid data layer.
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- “grid project”:allows the user to choose an existing grid system.
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- “grid”: it allows choosing a specific grid data layer to provide the target dimensions for the output
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grid data layer. The numeric data type used in the chosen grid data layer will be the same type used
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in the output grid data layer.
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- ``Distance Weighting[Selection]``:
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- ``Inverse Distance Power[Number]``:
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The degree of the equation used in the interpolation
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- ``Exponential and Gaussian Weighting Bandwidth[Number]``:
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- ``Search Range[Selection]``:
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The distance out from each known data point the algorithm will search to locate additional known data
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points for use in the interpolation equation. The default is 100.
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- ``Search Radius[Number]``:
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- ``Search Mode[Selection]``:
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There are two search modes to choose. The default is “all directions”. The second choice is “quadrants”.
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In this case, the search will be on a quadrant basis. When it finds the ‘Maximum Points’ in the quadrant,
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it will move to the next point object.
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- ``Number of Points[Selection]``:
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- ``Maximum Number of Points[Number]``:
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Identifies how many points will be sought for use in the interpolation formula.
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The default maximum number of points is 10.
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- ``Output extent[Extent]``:
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- ``Cellsize[Number]``:
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Outputs
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-------
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- ``Grid[Raster]``:
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See also
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---------
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Console usage
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-------------
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::
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processing.runalg('saga:inversedistanceweighted', shapes, field, target, weighting, power, bandwidth, range, radius, mode, points, npoints, output_extent, user_size, user_grid)
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Available options for selection parameters:
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target(Target Grid)
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0 - [0] user defined
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weighting(Distance Weighting)
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0 - [0] inverse distance to a power
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1 - [1] linearly decreasing within search radius
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2 - [2] exponential weighting scheme
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3 - [3] gaussian weighting scheme
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range(Search Range)
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0 - [0] search radius (local)
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1 - [1] no search radius (global)
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mode(Search Mode)
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0 - [0] all directions
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1 - [1] quadrants
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points(Number of Points)
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0 - [0] maximum number of points
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1 - [1] all points
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