Spatial_searching/searching_with_circular_query.cpp

#include <CGAL/Simple_cartesian.h>
#include <CGAL/Kd_tree.h>
#include <CGAL/Search_traits_2.h>
#include <CGAL/point_generators_2.h>
#include <CGAL/algorithm.h>
#include <CGAL/Fuzzy_sphere.h>
 
typedef CGAL::Simple_cartesian<double> K;
typedef K::Point_2 Point;
typedef CGAL::Random_points_in_square_2<Point> Random_points_iterator;
typedef CGAL::Counting_iterator<Random_points_iterator> N_Random_points_iterator;
typedef CGAL::Search_traits_2<K> Traits;
typedef CGAL::Fuzzy_sphere<Traits> Fuzzy_circle;
typedef CGAL::Kd_tree<Traits> Tree;
typedef CGAL::Random Random;
 
int main()
{
  const int N=1000;
 
  // generator for random data points in the square ( (-1,-1), (1,1) )
  Random rnd(0);
  Random_points_iterator rpit(1.0, rnd);
 
  // Insert also the N points in the tree
  Tree tree(N_Random_points_iterator(rpit,0),
            N_Random_points_iterator(N));
 
  // define default circular range query
  Point center(0.2, 0.2);
  Fuzzy_circle default_range(center, 0.2);
 
  std::optional<Point> any = tree.search_any_point(default_range);
  if(any)
    std::cout << *any << " is in the query circle\n";
  else
    std::cout << "Empty query circle\n";
 
  std::list<Point> result;
  tree.search(std::back_inserter(result), default_range);
 
  std::cout << "\nPoints in circle with center " << center << " and radius 0.2" << std::endl;
 
  std::list<Point>::iterator it;
  for (it=result.begin(); (it != result.end()); ++it)
    std::cout << *it << std::endl;
 
  result.clear();
  // approximate range searching using value 0.1 for fuzziness parameter
  Fuzzy_circle approximate_range(center, 0.2, 0.1);
 
  tree.search(std::back_inserter( result ), approximate_range);
 
  std::cout << "\n\nPoints in circle with center " << center << " and fuzzy radius [0.1,0.3]" << std::endl;
 
  for (it=result.begin(); (it != result.end()); ++it)
    std::cout << *it << std::endl;
 
  std::cout << "\ndone" << std::endl;
  return 0;
}