NAME¶
r.resamp.interp - Resamples raster map layers to a finer grid
using interpolation.
KEYWORDS¶
raster, resample
SYNOPSIS¶
r.resamp.interp
r.resamp.interp help
r.resamp.interp input=
name output=
name
[
method=
string] [--
overwrite] [--
verbose]
[--
quiet]
Flags:¶
- --overwrite
-
Allow output files to overwrite existing files
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
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 resamples an input raster map by interpolating between
the neighboring cells via a selectable resampling algorithm. All cells present
in the neighborhood of the input raster cell must be non-null to generate a
non-null cell in the output raster map. 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 (16 cells)
This module is intended for reinterpolation of continuous data to a different
resolution rather than for interpolation from scattered data (use the
v.surf.* modules for that purpose).
NOTES¶
Resampling modules (
r.resample, r.resamp.stats, r.resamp.interp,
r.resamp.rst) resample the map to match the current region settings.
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 (NULL propagation). This could occur due to the input cells being
outside the current region, being NULL or MASKed.
For longitude-latitude locations, the interpolation algorithm 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 interpolation method.
EXAMPLE¶
Resample elevation raster map to a higher resolution (from 500m to 250m; North
Carolina sample dataset):
g.region rast=elev_state_500m -p
g.region res=250 -ap
r.resamp.interp input=elev_state_500m output=elev_state_250m
SEE ALSO¶
g.region,
r.resample,
r.resamp.rst r.resamp.stats
AUTHOR¶
Glynn Clements
Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $
Full index
© 2003-2014 GRASS Development Team