v.histogram - GRASS GIS manual

Note: This document is for an older version of GRASS GIS that has been discontinued. You should upgrade, and read the current manual page.

NAME

KEYWORDS

SYNOPSIS

v.histogram map=name [layer=string] column=name [where=sql_query] plot_output=name [bins=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

map=name [required]: Name of vector map; Or data source for direct OGR access
layer=string: Layer number or name; Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.; Default: 1
column=name [required]: Attribute column to create histogram from
where=sql_query: WHERE conditions of SQL statement without 'where' keyword; Example: income < 1000 and population >= 10000
plot_output=name [required]: Name for graphic output file for plot (extension decides format, - for screen); Name for output file; Default: -
bins=integer: Number of bins in histogram; Default: 30

DESCRIPTION

v.histogram draws a histogram of the values in a vector map attribute column. Users can use the where option to only select a subset of the attribute table and can determine the number of bins (bars) used for the histogram. The plot_output parameter determines whether the result is displayed on screen (default) or exported to a graphics file.

NOTE

This is a quick and dirty solution using basic matplotlib. In future, this should be integrated into the g.gui, possibly together with the raster histogram tool.

EXAMPLE

v.histogram map=censusblk_swwake column=MEDIAN_AGE where="TOTAL_POP>0"

AUTHOR

SOURCE CODE

Latest change: Thursday Apr 18 16:03:04 2024 in commit: 32336efa800ee9cb0054596a731152f92e0cda3d