r.object.geometry - GRASS manual

NAME

r.object.geometry - Calculates geometry parameters for raster objects.

KEYWORDS

SYNOPSIS

r.object.geometry

r.object.geometry --help

r.object.geometry [-m] input=name [output=name] [separator=character] format=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-m: Use meters as units instead of cells
--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:

input=name [required]: Name of input raster map
output=name: Name for output file
separator=character: Field separator; Special characters: pipe, comma, space, tab, newline; Default: pipe
format=name [required]: Output format; Options: plain, json; Default: plain; plain: Plain text output; json: JSON (JavaScript Object Notation)

DESCRIPTION
EXAMPLE
SEE ALSO
AUTHORS

DESCRIPTION

r.object.geometry calculates form statistics of raster objects in the input map and writes it to the output text file (or standard output if no output filename or '-' is given), with fields separated by the chosen separator. Objects are defined as clumps of adjacent cells with the same category value (e.g. output of r.clump or i.segment).

By default, values are in pixels. If values in meters is desired, the user can set the -m flag. If the current working region is in lat-long or has non-square pixels, using meters is recommended.

Statistics currently calculated are exactly the same as in v.to.db (except for compact_square and mean coordinates):

area
perimeter
compact_square (compactness compared to a square: compact_square = 4 * sqrt(area) / perimeter)
compact_circle (compactness compared to a circle: compact_circle = perimeter / ( 2 * sqrt(PI * area) ))
fractal dimension ( fd = 2 * ( log(perimeter) / log(area + 0.001) ) )
mean x coordinate of object (in map units)
mean y coordinate of object (in map units)

EXAMPLE

g.region raster=soilsID
r.object.geometry input=soilsID output=soils_geom.txt

The format=json option can be used to change the output format to JSON:

r.object.geometry input=zipcodes format=json

[
    {
        "category": 1,
        "area": 106,
        "perimeter": 62,
        "compact_circle": 1.6987670351864215,
        "compact_square": 0.66423420264432265,
        "fd": 1.7699924681225903,
        "mean_x": 631382.07547169807,
        "mean_y": 222764.15094339623
    },
    {
        "category": 2,
        "area": 57,
        "perimeter": 36,
        "compact_circle": 1.3451172460704992,
        "compact_square": 0.83887049280786108,
        "fd": 1.772672742164326,
        "mean_x": 643460.52631578944,
        "mean_y": 217232.45614035087
    },
    {
        "category": 3,
        "area": 10,
        "perimeter": 16,
        "compact_circle": 1.4272992929222168,
        "compact_square": 0.79056941504209488,
        "fd": 2.4081353865496951,
        "mean_x": 631300,
        "mean_y": 215450
    },
    {
        "category": 4,
        "area": 63,
        "perimeter": 60,
        "compact_circle": 2.1324361862292305,
        "compact_square": 0.52915026221291817,
        "fd": 1.9764401337147652,
        "mean_x": 642345.23809523811,
        "mean_y": 226599.20634920636
    },
    {
        "category": 5,
        "area": 491,
        "perimeter": 156,
        "compact_circle": 1.9859985189304281,
        "compact_square": 0.56816717451693177,
        "fd": 1.6299200778082998,
        "mean_x": 637912.93279022397,
        "mean_y": 220636.96537678209
    },
    {
        "category": 6,
        "area": 83,
        "perimeter": 60,
        "compact_circle": 1.8578355639603314,
        "compact_square": 0.60736223860961991,
        "fd": 1.8531256328449071,
        "mean_x": 635846.38554216863,
        "mean_y": 227219.8795180723
    }
]

AUTHORS

Moritz Lennert
Markus Metz (diagonal clump tracing)

SOURCE CODE

Available at: r.object.geometry source code (history)

Latest change: Thursday Oct 02 14:39:13 2025 in commit: 1850489bf42c72d8dcfe2e4db1738441b4a7dc43