Density-Based Spatial Clustering of Applications with Noise (DBSCAN)

Quote:

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Originally Posted by wikipedia

Density-based spatial clustering of applications with noise (DBSCAN) is a data clustering algorithm. It is a density-based clustering algorithm because it finds a number of clusters starting from the estimated density distribution of corresponding nodes. DBSCAN is one of the most common clustering algorithms.

http://en.wikipedia.org/wiki/DBSCAN

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How to use:

1. Add Dbscan.vb to your project.
2. Add Dbscan.txt to your project, set the Copy to Output Directory property to Copy always on it.
3. Add a chart (from the System.Windows.Forms.DataVisualization namespace) to the form.
4. Add the code below to your form. (C# Version Here)

Code:

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Imports System.Windows.Forms.DataVisualization.Charting

Public Class Form1

#Region "fields"

    Private Shared ChartColors As Color() = New Color() {Color.FromArgb(&H41, 140, 240), Color.FromArgb(&HFC, 180, &H41), _
                                                        Color.FromArgb(&HE0, &H40, 10), Color.FromArgb(5, 100, &H92), _
                                                        Color.FromArgb(&HBF, &HBF, &HBF), Color.FromArgb(&H1A, &H3B, &H69), _
                                                        Color.FromArgb(&HFF, &HE3, 130), Color.FromArgb(&H12, &H9C, &HDD), _
                                                        Color.FromArgb(&HCA, &H6B, &H4B), Color.FromArgb(0, &H5C, &HDB), _
                                                        Color.FromArgb(&HF3, 210, &H88), Color.FromArgb(80, &H63, &H81), _
                                                        Color.FromArgb(&HF1, &HB9, &HA8), Color.FromArgb(&HE0, &H83, 10), _
                                                        Color.FromArgb(120, &H93, 190)}

#End Region

#Region "constructors"

    Public Sub New()
        Me.InitializeComponent()
        Me.InitializeChart()
    End Sub

#End Region

#Region "methods"

    Private Sub InitializeChart()
        Dim series As Series = Me.Chart1.Series(0)

        series.ChartType = SeriesChartType.Point
        series.MarkerStyle = MarkerStyle.Circle
        series.MarkerSize = 10

        Me.Chart1.Legends(0).Enabled = False

        Me.Chart1.ChartAreas(0).AxisX.LabelStyle.Format = "N3"
        Me.Chart1.ChartAreas(0).AxisX.MajorGrid.Enabled = False

        Me.Chart1.ChartAreas(0).AxisY.LabelStyle.Format = "N3"
        Me.Chart1.ChartAreas(0).AxisY.MajorGrid.Enabled = False
    End Sub

    Protected Overrides Sub OnLoad(e As EventArgs)
        MyBase.OnLoad(e)

        ' generate chart based on Dbscan.txt
        Me.GenerateClusters()
    End Sub

    Private Sub GenerateClusters()

        Dim points As New List(Of DbscanPoint)()

        ' change path as appropriate
        Dim lines = System.IO.File.ReadAllLines("Dbscan.txt")

        For Each line In lines
            Dim split = line.Split(" "c)

            points.Add(New DbscanPoint(Convert.ToDouble(split(1)), Convert.ToDouble(split(2))))
        Next

        ' customize the epsilion radius and minimum cluster points here
        ' note: if you are using http://people.cs.nctu.edu.tw/~rsliang/dbscan/testdatagen.html
        '      to generate data, make sure these parameters match the parameters on the site
        '      otherwise you will get different results
        DbscanAlgorithm.Dbscan(points.ToArray(), 4.0, 6)

        Dim series = Me.Chart1.Series(0)

        For Each item In points
            Dim p = series.Points(series.Points.AddXY(item.X, item.Y))

            If item.IsNoise Then
                p.Color = SystemColors.Control
            Else
                p.Color = Form1.ChartColors((item.ClusterId.Value - 1) Mod Form1.ChartColors.Length)
            End If
        Next
    End Sub

#End Region

End Class


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You should see this if everything was successful:

Attachment 110939

Here's how you can generate test data (this is what I verified the algorithm against): http://people.cs.nctu.edu.tw/~rslian...stdatagen.html.