VTK/Examples/Cxx/DataStructures/KdTreePointLocatorClosestPoint

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This example creates a set of three points, builds a KDTree from them, then demonstrates how to find the closest point to a query point.

KdTreePointLocatorClosestPoint.cxx

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkIdList.h>
#include <vtkKdTreePointLocator.h>
 
int main(int, char *[])
{
  // Setup point coordinates
  double x[3] = {1.0, 0.0, 0.0};
  double y[3] = {0.0, 1.0, 0.0};
  double z[3] = {0.0, 0.0, 1.0};
 
  vtkSmartPointer<vtkPoints> points = 
    vtkSmartPointer<vtkPoints>::New();
  points->InsertNextPoint(x);
  points->InsertNextPoint(y);
  points->InsertNextPoint(z);
 
  vtkSmartPointer<vtkPolyData> polydata = 
    vtkSmartPointer<vtkPolyData>::New();
  polydata->SetPoints(points);
 
  // Create the tree
  vtkSmartPointer<vtkKdTreePointLocator> kDTree = 
    vtkSmartPointer<vtkKdTreePointLocator>::New();
  kDTree->SetDataSet(polydata);
  kDTree->BuildLocator();
 
  double testPoint[3] = {2.0, 0.0, 0.0};
 
  // Find the closest points to TestPoint
  vtkIdType iD = kDTree->FindClosestPoint(testPoint);
  std::cout << "The closest point is point " << iD << std::endl;
 
  //Get the coordinates of the closest point
  double closestPoint[3];
  kDTree->GetDataSet()->GetPoint(iD, closestPoint);
  std::cout << "Coordinates: " << closestPoint[0] << " " << closestPoint[1] << " " << closestPoint[2] << std::endl;
 
  return EXIT_SUCCESS;
}

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CMakeLists.txt

cmake_minimum_required(VERSION 2.8)
 
PROJECT(KdTreePointLocatorClosestPoint)
 
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
 
add_executable(KdTreePointLocatorClosestPoint MACOSX_BUNDLE KdTreePointLocatorClosestPoint.cxx)
 
if(VTK_LIBRARIES)
  target_link_libraries(KdTreePointLocatorClosestPoint ${VTK_LIBRARIES})
else()
  target_link_libraries(KdTreePointLocatorClosestPoint vtkHybrid vtkWidgets)
endif()

Download and Build KdTreePointLocatorClosestPoint

Click here to download KdTreePointLocatorClosestPoint. and its CMakeLists.txt file.

Once the tarball KdTreePointLocatorClosestPoint.tar has been downloaded and extracted,

cd KdTreePointLocatorClosestPoint/build 
  • If VTK is installed:
cmake ..
  • If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./KdTreePointLocatorClosestPoint

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.