Note: This addon document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade your GRASS GIS installation, and read the current addon manual page.
NAME
d.vect.colhist - Draws the histogram of values in a vector attribute column
KEYWORDS
display,
vector,
geology
SYNOPSIS
d.vect.colhist
d.vect.colhist --help
d.vect.colhist 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 containing azimuth
- 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
d.vect.colhist draws a histogram of the values in a vector
map attribute column. The user 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.
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.
Show the histogram of median age values in the census block map:
d.vect.colhist map=censusblk_swwake column=MEDIAN_AGE where="TOTAL_POP>0"
Histogram of median age values of census blocks
Moritz Lennert
SOURCE CODE
Available at:
d.vect.colhist source code
(history)
Latest change: Mon Jun 28 07:54:09 2021 in commit: 1cfc0af029a35a5d6c7dae5ca7204d0eb85dbc55
Note: This addon document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade your GRASS GIS installation, and read the current addon manual page.
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GRASS Development Team,
GRASS GIS 7.8.8dev Reference Manual