Flags:¶

--help

Print usage summary

--verbose

Verbose module output

--quiet

Quiet module output

--ui

Force launching GUI dialog

Parameters:¶

map=name [required]

Name of raster map

cats=range[,range,...]

Category values
Example: 1,3,7-9,13

values=float[,float,...]

Comma separated value list
Example: 1.4,3.8,13

separator=character

Field separator
Special characters: pipe, comma, space, tab, newline
Default: tab

raster=name

Raster map from which to copy category table

rules=name

File containing category label rules (or "-" to read from stdin)

format=string

Default label or format string for dynamic labeling
Used when no explicit label exists for the category

coefficients=mult1,offset1,mult2,offset2

Dynamic label coefficients
Two pairs of category multiplier and offsets, for $1 and $2

Input from a file¶

The rules option allows the user to assign category labels from values found in a file (without header). The label can refer to a single category, range of categories, floating point value, or a range of floating point values. The format is given as follows (when separator is set to colon; no white space must be used after the separator):

cat:Label
val1:val2:Label

If the filename is given as "-", the category labels are read from stdin

Default and dynamic category labels¶

Default and dynamic category labels can be created for categories that are not explicitly labeled. The coefficient line can be followed by explicit category labels which override the format label generation.

   0:no data


   2:	.


   5:	.		      ## explicit category labels


   7:	.

explicit labels can be also of the form:

   5.5:5:9 label description


   or


   15:30  label description

In the format line

Also, the form $?xxx$yyy$ translates into yyy if the category is 1, xxx otherwise. The $yyy$ is optional. Thus

$1 meter$?s

will become:
1 meter (for category 1)
2 meters (for category 2), etc.

format=’Elevation: $1.2 to $2.2 feet’ ## Format Statement
coefficients="5.0,1000,5.0,1005" ## Coefficients

The format and coefficients above would be used to generate the following statement in creation of the format appropriate category string for category "num":

sprintf(buff,"Elevation: %.2f to %.2f feet", num*5.0+1000, num*5.0*1005)

Note: while both the format and coefficient lines must be present a blank line for the format string will effectively suppress automatic label generation.

To use a "$" in the label without triggering the plural test, put "$$" in the format string.

Use ’single quotes’ when using a "$" on the command line to avoid unwanted shell substitution.

Printing categories¶

r.category map=landclass96
1	developed
2	agriculture
3	herbaceous
4	shrubland
5	forest
6	water
7	sediment

prints the values and labels associated with all of the categories in the landclass96 raster map layer.

r.category map=landclass96 cats=2,5-7
2	agriculture
5	forest
6	water
7	sediment

r.category map=landclass96 cats=3,4 separator=comma
3,herbaceous
4,shrubland

Adding categories¶

Example for defining new category labels, using a colon as separator:

r.category diseasemap separator=":" rules=- << EOF
1:potential absence
2:potential presence
EOF

This sets the categoy values 1 and 2 to respective text labels. Alternatively, the rules can be stored in an ASCII text file and loaded via the rules parameter.