d.histogram(1)

NAME
d.histogram - Displays a histogram in the form of a pie or bar chart for a user-specified raster map.

KEYWORDS
display, histogram, statistics

SYNOPSIS
d.histogram
d.histogram --help
d.histogram [-nc] map=name [style=string] [color=name] [bgcolor=name] [nsteps=integer] [--help] [--verbose] [--quiet] [--ui]

  Flags:

-n
    Display information for null cells

-c
    Report for ranges defined in cats file (fp maps only)

--help
    Print usage summary

--verbose
    Verbose module output

--quiet
    Quiet module output

--ui
    Force launching GUI dialog

  Parameters:

map=name [required]
    Raster map for which histogram will be displayed

style=string
    Indicate if a pie or bar chart is desired
    Options: pie, bar
    Default: bar

color=name
    Color for text and axes
    Either a standard color name or R:G:B triplet
    Default: black

bgcolor=name
    Background color
    Either a standard color name, R:G:B triplet, or "none"
    Default: white

nsteps=integer
    Number of steps to divide the data range into (fp maps only)
    Default: 255

DESCRIPTION
d.histogram displays the category-value distribution for a user-specified raster map layer, in the form of a bar chart or a pie chart. The display will be displayed in the active display frame on the graphics monitor, using the colors in the raster map layer’s color table. The program determines the raster map’s category value distribution by counting cells.

NOTES
d.histogram respects the current geographic region settings and the current MASK (if one exists).

d.histogram uses the colors in the map’s color look-up table (i.e., the map’s colr or colr2 file).

EXAMPLES
Running the command below will generate the bar graph shown in the figure:

g.region raster=elevation -p
d.mon wx0
d.histogram map=elevation

Figure: Bar graph histogram for elevation map

Running the command below will generate the pie graph shown in the figure:

g.region raster=landuse96_28m -p
d.histogram map=landuse96_28m style=pie

Figure: Pie graph histogram for landuse map

SEE ALSO
d.colortable, d.frame, d.graph, d.linegraph, d.mon, d.polar, g.region, r.stats

AUTHOR
Dave Johnson
DBA Systems, Inc.
10560 Arrowhead Drive
Fairfax, Virginia 22030

SOURCE CODE

Available at: d.histogram source code (history)

Accessed: Monday Jul 13 00:50:41 2026

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