# BoxChart

VTKExamples/Cxx/Plotting/BoxChart

### Description

This example demonstrates how to generate a box plot.

The example uses data from the Michelson Morley experiment. Compare the wiki example output with the Wikipedia results

Warning

The ChartBox expects an input table with exactly 5 rows per column. The 5 rows are minimum, 1st quartile, median, 3rd quartile and maximum. vtkComputeQuartiles is used to create a valid input table from the original data.

### Code

BoxChart.cxx

    #include "vtkSmartPointer.h"

    #include "vtkChartBox.h"
    #include "vtkStatisticsAlgorithm.h"
    #include "vtkComputeQuartiles.h"
    #include "vtkContextScene.h"
    #include "vtkContextView.h"
    #include "vtkIntArray.h"
    #include "vtkLookupTable.h"
    #include "vtkPlotBox.h"
    #include "vtkRenderer.h"
    #include "vtkRenderWindow.h"
    #include "vtkRenderWindowInteractor.h"
    #include "vtkStringArray.h"
    #include "vtkTable.h"
    #include "vtkAxis.h"
    #include "vtkTextProperty.h"

    //----------------------------------------------------------------------------
    int main(int , char* [])
    {
      // Set up a 2D scene, add an XY chart to it
      vtkSmartPointer<vtkContextView> view =
        vtkSmartPointer<vtkContextView>::New();
      view->GetRenderWindow()->SetSize(400, 400);
      view->GetRenderWindow()->SetMultiSamples(0);

      vtkSmartPointer<vtkChartBox> chart =
        vtkSmartPointer<vtkChartBox>::New();
      view->GetScene()->AddItem(chart);

      // Creates a vtkPlotBox input table
      int numParam = 5;
      vtkSmartPointer<vtkTable> inputBoxPlotTable =
        vtkSmartPointer<vtkTable>::New();

      for (int i = 0; i < numParam; i++)
      {
        char num[10];
        sprintf(num, "Run %d", i + 1);
        vtkSmartPointer<vtkIntArray> arrIndex =
          vtkSmartPointer<vtkIntArray>::New();
        arrIndex->SetName(num);
        inputBoxPlotTable->AddColumn(arrIndex);
      }

      inputBoxPlotTable->SetNumberOfRows(20);
      double values[20][5] =
        {
          {850,     960,     880,     890,     890},
          {740,     940,     880,     810,     840},
          {900,     960,     880,     810,     780},
          {1070,    940,     860,     820,     810},
          {930,     880,     720,     800,     760},
          {850,     800,     720,     770,     810},
          {950,     850,     620,     760,     790},
          {980,     880,     860,     740,     810},
          {980,     900,     970,     750,     820},
          {880,     840,     950,     760,     850},
          {1000,    830,     880,     910,     870},
          {980,     790,     910,     920,     870},
          {930,     810,     850,     890,     810},
          {650,     880,     870,     860,     740},
          {760,     880,     840,     880,     810},
          {810,     830,     840,     720,     940},
          {1000,    800,     850,     840,     950},
          {1000,    790,     840,     850,     800},
          {960,     760,     840,     850,     810},
          {960,     800,     840,     780,     870}
        };
      for (int j = 0; j < 20; ++j)
      {
        for (int i = 0; i < 5; ++i)
        {
          inputBoxPlotTable->SetValue(j, i, values[j][i]);
        }
      }
      vtkSmartPointer<vtkComputeQuartiles> quartiles =
        vtkSmartPointer<vtkComputeQuartiles>::New();
      quartiles->SetInputData(vtkStatisticsAlgorithm::INPUT_DATA, inputBoxPlotTable);
      quartiles->Update();

      vtkTable *outTable = quartiles->GetOutput();
      vtkSmartPointer<vtkLookupTable> lookup =
        vtkSmartPointer<vtkLookupTable>::New();
      lookup->SetNumberOfColors(5);
      lookup->SetRange(0, 4);
      lookup->Build();

      chart->GetPlot(0)->SetInputData(outTable);
      chart->SetShowLegend(true);
      chart->SetColumnVisibilityAll(true);
      chart->SetTitle("Michelson-Morley experiment");
      chart->GetTitleProperties()->SetFontSize(16);
      chart->GetYAxis()->SetTitle("Speed of Light (km/s - 299000)");

      // Set the labels
      vtkSmartPointer<vtkStringArray> labels =
        vtkSmartPointer<vtkStringArray>::New();
      labels->SetNumberOfValues(5);
      labels->SetValue(0, "Run 1");
      labels->SetValue(1, "Run 2");
      labels->SetValue(2, "Run 3");
      labels->SetValue(3, "Run 4");
      labels->SetValue(4, "Run 5");
      chart->GetPlot(0)->SetLabels(labels);

      // Render the scene
      view->GetRenderWindow()->SetMultiSamples(0);
      view->GetRenderer()->SetBackground(.8, .8, .8);
      view->GetInteractor()->Initialize();
      view->Render();
      view->GetInteractor()->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(BoxChart)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(BoxChart MACOSX_BUNDLE BoxChart.cxx )

    target_link_libraries(BoxChart ${VTK_LIBRARIES})

### Download and Build BoxChart

Click here to download BoxChart and its CMakeLists.txt file. Once the tarball BoxChart.tar has been downloaded and extracted,

    cd BoxChart/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:

    ./BoxChart

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.