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r.recode

Recodes categorical raster maps.

r.recode [-ad] input=name output=name rules=name [title=string] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.recode input=name output=name rules=name

grass.script.run_command("r.recode", input, output, rules, title=None, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("r.recode", input="name", output="name", rules="name")

Parameters

input=name [required]
    Name of raster map to be recoded
output=name [required]
    Name for output raster map
rules=name [required]
    File containing recode rules
    '-' for standard input
title=string
    Title for output raster map
-a
    Align the current region to the input raster map
-d
    Force output to 'double' raster map type (DCELL)
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

input : str, required
    Name of raster map to be recoded
    Used as: input, raster, name
output : str, required
    Name for output raster map
    Used as: output, raster, name
rules : str, required
    File containing recode rules
    '-' for standard input
    Used as: input, file, name
title : str, optional
    Title for output raster map
flags : str, optional
    Allowed values: a, d
    a
        Align the current region to the input raster map
    d
        Force output to 'double' raster map type (DCELL)
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

r.recode creates an output raster map by recoding input raster map based on recode rules. A title for the output raster map may be (optionally) specified by the user.

The recode rules can be read from standard input (i.e., from the keyboard, redirected from a file, or piped through another program) by entering rules=-.

Rules are defined in one of these formats:

old_low:old_high:new_low:new_high
old_low:old_high:new_val  (i.e. new_high == new_low)
*:old_val:new_val         (interval [inf, old_val])
old_val:*:new_val         (interval [old_val, inf])

r.recode is loosely based on r.reclass and uses the GRASS Reclass Library to convert the rasters. It has routines for converting to every possible combination of raster (eg. CELL to DCELL, DCELL to FCELL, etc). Standard floating point raster precision is float (FCELL), with -d double precision (DCELL) will be written.

There are four basic routines that it accepts:

  1. old-low to old-high is reclassed to new-low to new high , where the user provides all four values. The program figures on the fly what type of raster should be created.
  2. old-low to old-high is reclassed to a single new value. Anything outside the range is null.
  3. * to old-high will reclass everything less than old-high to a single new value.
  4. old-low to * will reclass everything greater than old-low to a single new value.

These four sets of arguments can be given on the command line, or piped via stdin or a file. More than one set of arguments is accepted.

EXAMPLES

Map type conversion

To simply convert a raster between formats (eg. int to float) the user would use the first argument. For example

10:1500:0.1:15.0

would convert an input raster map with range between 10 and 1500 to a float raster raster with range between 0.1 and 15.0.

Value replacement

r.recode can be used to replace existing cell values by others. The formatting is as described above. In following example the values 1, 2 and 3 are replaced by 1.1, 7.5 resp. 0.4:

r.recode input=oldmap output=newmap rules=- << EOF
1:1:1.1:1.1
2:2:7.5:7.5
3:3:0.4:0.4
EOF

SEE ALSO

r.reclass

AUTHOR

CERL

SOURCE CODE

Available at: r.recode source code (history)
Latest change: Friday Feb 07 19:16:09 2025 in commit a82a39f