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v.hull - Produces a convex hull for a given vector map.


vector, geometry


v.hull help
v.hull [-af] input=name output=name [--overwrite] [--verbose] [--quiet]


Use all vector points (do not limit to current region)
Create a 'flat' 2D hull even if the input is 3D points
Allow output files to overwrite existing files
Verbose module output
Quiet module output


Name of input vector map
For vector lines reads their vertices
Name for output vector map


v.hull computes the convex hull of a vector map and outputs the convex hull polygon as a vector area map. The convex hull, or convex envelope, for an object or a set of objects is the minimal convex set containing the given objects. This module creates a vector polygon containing all vector points or lines of the input map.

In the case of 3D input points, the hull will be a 3D hull as well, unless the user specifies the -f flag. The 3D hull will be composed of triangular faces.

Fig: Convex hull polygon created with v.hull


Example of v.hull 3D output (using two random 3D point clouds, North Carolina sample data set):
g.region rural_1m -p
r.mapcalc "zero = 0"
v.random -z output=random3d_a n=10 zmin=0 zmax=200
v.random -z output=random3d_b n=15 zmin=400 zmax=600
v.hull input=random3d_a output=random3d_a_hull
v.hull input=random3d_b output=random3d_b_hull
nviz elevation=zero vect=random3d_a_hull,random3d_b_hull


  • M. de Berg, M. van Kreveld, M. Overmars, O. Schwarzkopf, (2000). Computational geometry, chapter 1.1, 2-8.
  • J. O'Rourke, (1998). Computational Geometry in C (Second Edition), chapter 4.




    Andrea Aime, Modena, Italy
    Markus Neteler, ITC-irst (update to 5.7)
    Benjamin Ducke, CAU Kiel (3D hull support)
    Martin Landa, CTU in Prague, Czech Republic (vector lines support)

    Last changed: $Date: 2013-04-14 01:55:49 -0700 (Sun, 14 Apr 2013) $

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