GRASS logo

NAME

v.concave.hull - Creates a concave hull around points.

KEYWORDS

vector, geometry, alpha shape

SYNOPSIS

v.concave.hull
v.concave.hull --help
v.concave.hull input=name output=name [threshold=float] [--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:

input=name [required]
Input points
Or data source for direct OGR access
output=name [required]
Name for output vector map
threshold=float
Lower values make the hull more concave
Options: 0-10
Default: 7

Table of contents

DESCRIPTION

v.concave.hull creates a concave hull around points. Contrary to a convex hull, a concave hull can describe the shape of a point cloud.

EXAMPLES

Creating a convex and a concave hull

Creating a convex and a concave hull around schools_wake in the North Carolina sample dataset: 
v.hull in=schools_wake out=schools_wake_convex
v.concave.hull in=schools_wake out=schools_wake_concave

Convex hull around schools:

convex hull

Concave hull around schools:

concave hull

Creating Alpha shapes

Alpha shapes around points (left: threshold=8; right: threshold=0.5):

Alpha shape threshold=8   Alpha shape threshold=0.5

SEE ALSO

v.hull, v.buffer,, v.kernel

AUTHOR

Markus Metz

SOURCE CODE

Available at: v.concave.hull source code (history)

Main index | Vector index | Topics index | Keywords index | Graphical index | Full index

© 2003-2020 GRASS Development Team, GRASS GIS 7.8.3dev Reference Manual