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NAME

v.surf.bspline - Bicubic or bilineal interpolation with Tykhonov regularization

KEYWORDS

vector, interpolation

SYNOPSIS

v.surf.bspline
v.surf.bspline help
v.surf.bspline input=name [input_ext=name] [output=name] [raster_out=name] [database=string] [driver=string] [sie=float] [sin=float] [type=string] [lambda_i=float] [--overwrite]

Flags:

--overwrite
Force overwrite of output files

Parameters:

input=name
Name of input vector map
input_ext=name
Name of input vector map of sparse points
output=name
Name of output vector map
raster_out=name
Name of output raster map
database=string
Database name
driver=string
Driver name
Options: ogr,pg,sqlite,mysql,mesql,odbc,dbf
sie=float
Interpolation spline step value in east direction
Default: 4
sin=float
Interpolation spline step value in north direction
Default: 4
type=string
Spline type of interpolation
Options: bilinear,bicubic
Default: bilinear
lambda_i=float
Thychonov regularization weigth
Default: 1

DESCRIPTION

v.surf.bspline makes a bilinear/bicubic interpolation with Tykhonov regularization. The required input is a vector of only points that will be used for interpolate a reference surface. If an extra input vector is used, an estimation using the reference surface will be done on the points of this last vector. In other case, the interpolation will be done with the points of the former vector. The output format can be a vector in which case the interpolation will be done on the sparse points, or a raster map. In this last case, the interpolation will be on a regular grid.

EXAMPLES

Basic interpolation

v.surf.bspline input=point_vector output=interpolate_surface type=bicubic

In this case, a bicubic spline interpolation will be done and an estimation of the points of vector will be the output.

Basic interpolation and raster output with a long spline step

v.surf.bspline input=point_vector raster_out=interpolate_surface sie=25 sin=25

Now, a bilinear spline interpolation will be done on a grid.

Estimation on sparse points

v.surf.bspline input=point_vector int_ext=sparse_points output=interpolate_surface

In this last case, an estimation of the point within sparse points will be done using the parameters estimated with the points of point_vector.

AUTHORS

Original version of the program in GRASS 5.4: (s.bspline.reg)
Maria Antonia Brovelli, Massimiliano Cannata, Ulisse Longoni, Mirko Reguzzoni

Updates for GRASS 6:
Roberto Antolin

Last changed: $Date: 2006/09/05 02:59:46 $


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