How to create a histogram graph

Summary

The code in this topic demonstrates how to create a histogram graph and adjust its properties.

Creating a histogram graph

• pathToShapeFile - Path to shapefile to build the histogram.
• seriesFieldName - Numerical field to use to build the histogram.
• pathToOutImage - Output file containing an image of the graph. Refer to the application programming interface (API) documentation for the appropriate format extension in IDataGraphBase.ExportToFile).

[VB.NET]

Namespace ConsoleApplication1VBNET

Class Program
    Shared Sub Main(ByVal args() As String)
    Dim ao As IAoInitialize=New AoInitializeClass()
    ao.Initialize(esriLicenseProductCode.esriLicenseProductCodeBasic)
    SampleHistogram(@"path to your shapefile", "field name", binCount , @"path to your output image")
    ao.Shutdown()
End Sub

Shared Sub SampleHistogram(ByVal pathToShapeFile As String, ByVal seriesFieldName As String, ByVal binCount As Integer, ByVal pathToOutImage As String)
' Open a workspace for the input shapefile.
Dim shapefileWorkspaceFactory As IWorkspaceFactory=New ShapefileWorkspaceFactoryClass()
Dim shapefileWorkspace As IWorkspace
shapefileWorkspace=shapefileWorkspaceFactory.OpenFromFile(System.IO.Path.GetDirectoryName(pathToShapeFile), 0)
Dim featureWorkspace As IFeatureWorkspace=CType(shapefileWorkspace, IFeatureWorkspace)
' Create a data graph.
Dim dataGraphT As IDataGraphT=New DataGraphTClass()
' Get the table for the input shapefile.
Dim table As ITable=CType(featureWorkspace.OpenFeatureClass(System.IO.Path.GetFileNameWithoutExtension(pathToShapeFile)), ITable)

' Add the histogram series.
Dim seriesProps As ISeriesProperties=dataGraphT.AddSeries("bar:histogram")
seriesProps.SourceData=table
seriesProps.SetField(0, seriesFieldName)
' Set the histogram properties.
Dim histogramSeriesProps As IHistogramSeriesProperties=CType(seriesProps, IHistogramSeriesProperties)
histogramSeriesProps.BinCount=binCount
' Set titles.
dataGraphT.GeneralProperties.Title="Histogram of " + seriesFieldName
dataGraphT.AxisProperties(0).Title="COUNT"
' Update the data graph.
dataGraphT.Update(Nothing)
' Export the graph to file (the format depends on the file extension).
dataGraphT.ExportToFile(pathToOutImage)
End Sub

End Class

End Namespace

[C#]

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            IAoInitialize ao=new AoInitializeClass();
            ao.Initialize(esriLicenseProductCode.esriLicenseProductCodeBasic);
            SampleHistogram("path to your shapefile", "field name", binCount, 
                "path to your output image")ao.Shutdown();
        }

        static void SampleHistogram(String pathToShapeFile, String seriesFieldName,
            int binCount, String pathToOutImage)
        {
            // Open a workspace for the input shapefile.
            IWorkspaceFactory shapefileWorkspaceFactory=new
                ShapefileWorkspaceFactoryClass();
            IWorkspace shapefileWorkspace;
            shapefileWorkspace=shapefileWorkspaceFactory.OpenFromFile
                (System.IO.Path.GetDirectoryName(pathToShapeFile), 0);
            IFeatureWorkspace featureWorkspace=(IFeatureWorkspace)
                shapefileWorkspace;
            // Create a data graph.
            IDataGraphT dataGraphT=new DataGraphTClass();
            // Get the table for the input shapefile.
            ITable table=(ITable)featureWorkspace.OpenFeatureClass
                (System.IO.Path.GetFileNameWithoutExtension(pathToShapeFile));

            // Add the histogram series.
            ISeriesProperties seriesProps=dataGraphT.AddSeries("bar:histogram");
            seriesProps.SourceData=table;
            seriesProps.SetField(0, seriesFieldName);
            // Set the histogram properties.
            IHistogramSeriesProperties histogramSeriesProps=
                (IHistogramSeriesProperties)seriesProps;
            histogramSeriesProps.BinCount=binCount;
            // Set titles.
            dataGraphT.GeneralProperties.Title="Histogram of " + seriesFieldName;
            dataGraphT.VerticalAxisProperties.Title="COUNT";
            // Update the data graph.
            dataGraphT.Update(null);
            // Export the graph to file (the format depends on the file extension).
            dataGraphT.ExportToFile(pathToOutImage);
        }
    }
}

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To use the code in this topic, reference the following assemblies in your Visual Studio project. In the code files, you will need using (C#) or Imports (VB .NET) directives for the corresponding namespaces (given in parenthesis below if different from the assembly name):

• ESRI.ArcGIS.System (ESRI.ArcGIS.esriSystem)
• ESRI.ArcGIS.Geodatabase
• ESRI.ArcGIS.DataSourcesFile
• ESRI.ArcGIS.Catalog
• ESRI.ArcGIS.Display
• ESRI.ArcGIS.Carto
• ESRI.ArcGIS.CartoUI
• System
• System.Collections.Generic
• System.Text

Development licensing	Deployment licensing
ArcGIS Desktop Basic	ArcGIS Desktop Basic
ArcGIS Desktop Standard	ArcGIS Desktop Standard
ArcGIS Desktop Advanced	ArcGIS Desktop Advanced