GEOS is an open source geometry engine.

GEOS includes functions to compute:

  • buffer computation;
  • centroid of an area geometry;
  • convex hull;
  • Delaunay triangulation;
  • diameter of a geometry;
  • Hausdorff distance;
  • interior point of an areal, linear, or point geometry;
  • intersection of two line segments;
  • count of intersections of horizontal ray with polygon;
  • rectangle enclosing a geometry;
  • Voronoi polygons;

Web Site:

The GEOS home page at the TRAC Open Source Project site:



On any ARC cluster, check the installation details
by typing "module spider geos".

GEOS requires that the appropriate modules be loaded before it can be used.
One version of the appropriate commands for use on NewRiver is:

module purge
module load geos/3.4.2


The following batch file compiles and loads a user program with the
GEOS library, reads a file containing the coordinates of points in the
plane, and then computes various related geometric quantities.

#! /bin/bash
#PBS -l walltime=00:05:00
#PBS -l nodes=1:ppn=1
#PBS -W group_list=newriver
#PBS -q open_q
#PBS -j oe
module purge
module load geos/3.4.2
gcc -c -I $GEOS_INC geostest.c
gcc -o geostest geostest.o -L$GEOS_LIB -lgeos_c
./geostest test.wkt

A complete set of files to carry out a similar process are available in