Regrid

Category

Realization

Function

Maps scattered points onto a grid.

Syntax

output = Regrid(input, grid, nearest, radius, exponent, missing);

Inputs

Name	Type	Default	Description
input	field or vector list	none	field with positions to regrid
grid	field	none	grid to be used as template
nearest	integer or string	1	number of nearest neighbors to use
radius	scalar or string	"infinity"	radius from grid point
exponent	scalar	1.0	weighting exponent
missing	value	no default	missing value to be inserted if necessary

Outputs

Name	Type	Description
output	field	regridded field

Functional Details

This module uses a specified set of scattered points (input) to assign data values to every position of a specified grid.

input	should be either (1) a field with a 1-, 2-, or 3-dimensional "positions" component or (2) a list of 1-, 2-, or 3-dimensional vectors. In the second case, the vectors are interpreted as positions.
grid	is required. It specifies the grid to be used as a base for creating a "connections" component. The dimensionality of positions in this grid must match that of the positions in input. The specified grid could be created with the Construct module.
nearest	must be an integer or the string "infinity." An integer value specifies the number of nearest points (to each grid point) to be used in computing an average data value for that grid point.
radius	specifies the maximum radius (from the grid point) within which the nearest neighbors can be found. The parameter must specify a scalar value or the string "infinity." if 0, will place the data on the nearest grid point. If more than 1 data values lie within 1/2 delta of a grid point, then the average value will be computed. (Very fast)
exponent	The averaging method is a weighted average. The expression for this average is 1/radius(exponent). The default value is 1.0, reducing the expression to the reciprocal of the radius.
missing	is used when radius is set to a value other than "infinity." The parameter specifies how to treat those grid points for which no points in input occur within the specified radius. If missing is not set, the module creates an "invalid positions" component, and grid points with no assigned data value are invalidated. If missing is set, the data value is inserted for the missing data values. It must match the data component of input in rank, type, and shape. All components that are position-dependent are treated in the same way as the "data" component.

Note: To remove invalidated positions, use the Include module. However, it is not necessary to remove invalidated positions in order to have them treated as invalid by other modules.

Components

Adds a "connections" component. The "positions" and "connections" components are those of grid while all components in input that depend on "positions" will be present in the output, modified by averaging.

If the grid input contains invalid positions and missing is not set, the grid's invalid positions are replaced with a new invalid positions component computed. If missing is set, then the invalid positions component from the grid input is kept and is in the output.

Example Visual Program

SIMPLE/Regrid.net

See Also

 Connect,  Construct,  Include,  AutoGrid