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v.what(1grass) GRASS User's Manual v.what(1grass)

NAME

v.what - Queries a vector map at given locations.

KEYWORDS

vector, querying, position

SYNOPSIS

v.what
v.what --help
v.what [-aidgjm] map=name[,name,...] [layer=string[,string,...]] [type=string[,string,...]] coordinates=east,north [distance=float] [columns=name[,name,...]] [format=name] [--help] [--verbose] [--quiet] [--ui]

Flags:


Print attribute information

Print attribute database connection information

Print topological information (debugging)
Prints internal information for topology debugging

Print the stats in shell script style [deprecated]
This flag is deprecated and will be removed in a future release. Use format=shell instead.

Print the stats in JSON [deprecated]
This flag is deprecated and will be removed in a future release. Use format=json instead.

Print multiple features for each map if they meet the criteria
For JSON, this places features under a "features" key

Print usage summary

Verbose module output

Quiet module output

Force launching GUI dialog

Parameters:


Name of vector map(s)

Layer number or name (’-1’ for all layers)
A single vector map can be connected to multiple database tables. This number determines which table to use. When used with direct OGR access this is the layer name.
Default: -1

Input feature type
Options: point, line, boundary, centroid, area, face, kernel
Default: point,line,area,face

Coordinates for query
’-’ for standard input

Query threshold distance
Default: 0

Name of attribute column(s)
Default: all columns

Output format
Options: plain, shell, json
plain: Plain text output
shell: shell script style output
json: JSON (JavaScript Object Notation)

DESCRIPTION

v.what outputs the category number value(s) associated with user-specified location(s) in user-specified vector map layer(s). This module was derived from the d.what.vect module by removing all interactive code and modification of the output for easy parsing. Using the -g flag generates script-style output which is easily parsable.

EXAMPLE

North Carolina sample dataset example:

Query polygon at given position: 

v.what zipcodes_wake coordinates=637502.25,221744.25

Find closest hospital to given position within given distance (search radius): 

v.what hospitals coordinates=542690.4,204802.7 distance=2000000

SEE ALSO

d.what.rast, d.what.vect, v.rast.stats, v.vect.stats, v.what.rast, v.what.rast3, v.what.vect

AUTHOR

Trevor Wiens
Edmonton, Alberta, Canada

SOURCE CODE

Available at: v.what source code (history)

Latest change: Sunday Oct 19 06:41:19 2025 in commit: 3852c52a6ee5ed16ab7c0d2129951ff2d4badb8b

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© 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual

GRASS 8.5.0