[GRASS-user] integration of sample.c algorithms into r.resample

[Paul Kelly]

On Thu, 17 Aug 2006, Dylan Beaudette wrote:

> On 8/17/06, Paul Kelly <paul-grass at stjohnspoint.co.uk> wrote:
>> 
>> To throw in another suggestion, how about r.resamp.interp? This it would
>> mean it would be adjacent in the manuals to the other resampling modules
>> (r.resample and r.resamp.rst) for anyone looking for them, and might also
>> imply that r.resample (the only one with the full word in its name) was
>> kind of a default, basic resampler whilst r.resamp.interp and r.resamp.rst
>> used more advanced and/or interesting resampling methods.
>> 
>
> That sounds good to me.

Well I would commit it to CVS if it's OK. I briefly edited the r.bilinear 
man page to create a rough manpage for r.resamp.interp (see below): are 
there any glaring errors?

Paul

r.resamp.interp(1)     Grass User's Manual     r.resamp.interp(1)

NAME
        r.resamp.interp   -  Resamples  raster  map  layers  using
        interpolation.

SYNOPSIS
        r.resamp.interp

        r.resamp.interp help

        r.resamp.interp  input=name  output=name   [method=string]
        [--overwrite]

    Flags:
        --overwrite

    Parameters:
        input=name
            Name of input raster map

        output=name
            Name for output raster map

        method=string
            Interpolation method Options: nearest,bilinear,bicubic
            Default: bilinear

DESCRIPTION
        r.resamp.interp fills a grid  cell  (raster)  matrix  with
        interpolated  values  generated  from a set of input layer
        data points. A choice of three  interpolation  methods  is
        available;  each  uses  the weighted values of a different
        number of adjacent cells in the input map to determine the
        value of each cell in the output map as follows:

                      nearest neighbour (1 cell)

                      bilinear (4 cells)

                      bicubic (12 cells)

        If there is a current working mask, it applies to the out­
        put raster file.  Only those cells falling within the mask
        will  be  assigned interpolated values.  The procedure for
        selection of input data will consider all input data rele­
        vant  to  interpolating  values at the cell centers of the
        current geographic region, ignoring the curent mask.  Note
        that  for bilinear and bicubic interpolation, cells of the
        output raster that cannot be bounded  by  the  appropriate
        number of input cell centers are set to null.

NOTES
        For  longitude-latitude databases, the interpolation algo­
        rithm is based on degree fractions, not  on  the  absolute
        distances  between cell centers.  Any attempt to implement
        the latter would violate the integrity of  the  interpola­
        tion method.

SEE ALSO
        g.region, r.resample, r.resamp.rst

AUTHOR
        Glynn Clements

        Last changed: $Date: 2003/04/30 15:17:25 $

        Full index

GRASS 6.3.cvs                                  r.resamp.interp(1)