NAME
r.what - Queries raster map layers on their category values and category labels.
(GRASS Raster Program)
SYNOPSIS
r.what
r.what help
r.what [-fci] input=name[,name,...]
[cache=value] [null=string]
[east_north=east,north[,east,north,...]]
r.what input=name[,name,...]
[other options] < inputfile
DESCRIPTION
r.what outputs the category values and (optionally) the category
labels associated with user-specified locations on raster input map(s).
Locations are specified as geographic x,y coordinate pairs (i.e., pair of
eastings and northings); the user can also (optionally)
associate a label with each location.
The program will be run non-interactively if the user specifies the program
parameter values and (optionally) a flag setting on the command line, using the form:
-
r.what [-fci] input=name[,name,...]
where each input name is the name of a raster map layer whose category values
are to be queried, and the (optional) flag -f directs r.what to also
output category labels.
The location or locations of sites to be queried are entered with the east_north option.
Multiple sites to be queried are entered separated by a comma.
Alternately, the user can redirect a user-created ASCII input file containing
a list of geographic coordinate pairs and (optionally) user-named labels, into
r.what using the form:
-
r.what [-fci] input=name[,name,...]
< inputfile
If the user does not enter coordinates with the east_north option or redirect an input
file containing these coordinates into the program, the program will query the user for point
locations and labels.
Thus, the user can simply type:
-
r.what
on the command line, without program arguments. In this case, the user will be prompted for the
flag setting and parameter values using the standard GRASS parser.
OPTIONS
Flags:
- -f
- Also output the category label(s) associated with the cell(s) at the user-specified location(s).
- -c
- Turn on cache reporting.
- -i
- Output integer category values, not cell values.
Parameters:
- input=name[,name,name,...]
- The name(s) of one or more existing raster map layers to be queried.
- cache=value
- Size of point cache.
- null=string
- Character string to represent no data cell.
- east_north=east,north[,east,north,...]
- Coordinates for query
EXAMPLES
The contents of the ASCII inputfile to r.what can be typed in at the keyboard,
redirected from a file, or piped from another program (like d.where).
Each line of the input consists of an easting, a northing, and an optional label, which are separated
by spaces. In interactive mode, the word end is typed to end input of coordinates to
r.what. For example:
-
- 635342.21 7654321.09 site 1
- 653324.88 7563412.42 site 2
- end
r.what output consists of the input geographic location and label, and, for each
user-named raster map layer, the category value, and (if -f is specified) the
category label associated with the cell(s) at this geographic location. Sample input
(in regular font) to and output (in plain text) from r.what are given below.
-
- r.what input=soils,aspect
- 635342.21 7654321.09 site 1
- 653324.88 7563412.42 site 2
- end
-
- 635342.21|7654321.09|site 1|45|21
- 653324.88|7563412.42|site 2|44|20
-
- r.what -f input=soils,aspect
- 635342.21 7654321.09 site 1
- 653324.88 7563412.42 site 2
end
-
- 635342.21|7654321.09|site 1|45|NaC|21|30 degrees NW
- 653324.88|7563412.42|site 2|44|NdC|20|15 degrees NW
Coordinates for query may be entered on the command line directly:
r.what input=soils,aspect east_north=635342.21,7654321.09,653324.88,7563412.42
635342.21|7654321.09|site 1|45|21
653324.88|7563412.42|site 2|44|20
NOTE
The maximum number of raster map layers that can be queried at one time is 150.
SEE ALSO
d.sites, d.where,
r.cats, r.report,
r.stats, r.series, parser
AUTHOR
Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
Last changed: $Date: 2003/08/25 03:55:49 $