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d.histogram

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

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

Example:

d.histogram map=name

grass.script.run_command("d.histogram", map, style="bar", color="black", bgcolor="white", nsteps=255, flags=None, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("d.histogram", map="name")

Parameters

map=name [required]
    Raster map for which histogram will be displayed
style=string
    Indicate if a pie or bar chart is desired
    Allowed values: 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
-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
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

map : str, required
    Raster map for which histogram will be displayed
    Used as: input, raster, name
style : str, optional
    Indicate if a pie or bar chart is desired
    Allowed values: pie, bar
    Default: bar
color : str, optional
    Color for text and axes
    Either a standard color name or R:G:B triplet
    Used as: input, color, name
    Default: black
bgcolor : str, optional
    Background color
    Either a standard color name, R:G:B triplet, or "none"
    Used as: input, color, name
    Default: white
nsteps : int, optional
    Number of steps to divide the data range into (fp maps only)
    Default: 255
flags : str, optional
    Allowed values: n, c
    n
        Display information for null cells
    c
        Report for ranges defined in cats file (fp maps only)
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

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 raster mask (if mask is active).

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

d.histogram bar graph example
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

d.histogram pie graph example
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)
Latest change: Wednesday Apr 02 16:37:00 2025 in commit a2fa5a0