1r.recode(1)                   Grass User's Manual                  r.recode(1)
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NAME

6       r.recode  - Recode raster maps.
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KEYWORDS

9       raster
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SYNOPSIS

12       r.recode
13       r.recode help
14       r.recode  [-ad]  input=string  output=string  [title=string]   [--over‐
15       write]
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17   Flags:
18       -a  Align the current region to the input map
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20       -d  Force output to double map type (DCELL)
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22       --overwrite
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24   Parameters:
25       input=string
26           Raster map to be recoded
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28       output=string
29           Name for the resulting raster map
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31       title=string
32           Title for the resulting raster map
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DESCRIPTION

35       r.recode creates an output map layer  based  on  an  input  raster  map
36       layer.  The  output map layer will be a recoding of the input map layer
37       based on recode rules input to r.recode. A title  for  the  output  map
38       layer may be (optionally) specified by the user.
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40       The  recode   rules  are  read from standard input (i.e., from the key‐
41       board, redirected from a file, or piped through another program).
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43       The program will be run non-interactively if  the  user  specifies  the
44       name of the raster map layer to be recoded, the name of an output layer
45       to hold recoded map, and (optionally) the name of a title for the  out‐
46       put map.  Rules are defined in one of these formats:
47           old_low:old_high:new_low:new_high
48           old_low:old_high:new_val  (i.e. new_high == new_low)
49           *:old_val:new_val         (interval [inf, old_val])
50           old_val:*:new_val         (interval [old_val, inf])
51         r.recode  is  loosely  based  on r.reclass and uses the GRASS reclass
52       library to convert the rasters. It has routines for converting to every
53       possible  combination  of  raster  (eg. int to double, double to float,
54       etc).  Standard floating point raster precision is float, with -d  dou‐
55       ble precision will be written.
56       There are four basic routines that it accepts:
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58       1      old-low  to old-high is reclassed to new-low to new high , where
59              the user provides all four values. The program  figures  on  the
60              fly what type of raster should be created.
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62       2      old-low to old-high is reclassed to a single new value. Anything
63              outside the range is null.
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65       3
66               * to old-high will reclass everything less than old-high  to  a
67              single new value.
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69       4
70               old-low  to * will reclass everything greater than old-low to a
71              single new value.
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73       These four sets of arguments can be given on the command line, or piped
74       via stdin or a file. More than one set of arguments is accepted.
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EXAMPLES

77       Map type conversion
78       To  simply convert a raster between formats (eg. int to float) the user
79       would use the first argument. For example
80       10:1500:0.1:15.0
81       would convert an old raster with range between 10 and 1500 to  a  float
82       raster with range bewteen 0.1 and 15.0.
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84       Value replacement
85       r.recode  can  be  used  to replace existing cell values by others. The
86       formatting is as described above. In following example the values 1,  2
87       and 3 are replaced by 1.1, 7.5 resp. 0.4:
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89           r.recode in=oldmap out=newmap << EOF
90           1:1:1.1:1.1
91           2:2:7.5:7.5
92           3:3:0.4:0.4
93           EOF
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AUTHOR

97       CERL
98
99       Last changed: $Date: 2003/05/06 15:20:26 $
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101       Full index
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105GRASS 6.2.2                                                        r.recode(1)