Polar chart has unequal angles

[User (Old forums)]

#19103 |

Hi, I have a very straightforward polar chart, with the standard 30 degrees between radial marker lines.  It is all working fine, but I notice that the angles between the radial marker lines are not equal.  The angles closer to vertical are smaller than those closer to horizontal.  It is quite noticeable – the difference between the biggest and smallest angles is almost 2 to 1.  I am using Stretch margin mode on the chart, and thought that might be causing it.  But I have tried tweaking it and cannot fix the problem.  Any ideas?  The examples in the Chart Explorer do not exhibit this problem.  I’m quite perplexed by this.  My chart software is version 4.0.6353.0 (on the dll).

 

Imported from legacy forums. Posted by Steve (had 2999 views)

[User (Old forums)]

#19104

Do you have a code snippet showing how you set up your chart, so we can try to reproduce on our side?

You can also try to upgrade to our latest version to see if it solves the issue (I’ll be testing with the latest version).

Imported from legacy forums. Posted by André (had 424 views)

[User (Old forums)]

#19105

Here is the code for the form and my code for handling what it does.  The polar series is predefined, and I simply fill it with values each time I need it.  But the unequal angles appear even in design view, so it is nothing to do with how it is being used.

 frmMainPolar.Designer.v ——————————————————————-

<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Class frmMainPolar
    Inherits System.Windows.Forms.Form

    ‘Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        Try
            If disposing AndAlso components IsNot Nothing Then
                components.Dispose()
            End If
        Finally
            MyBase.Dispose(disposing)
        End Try
    End Sub

    ‘Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    ‘NOTE: The following procedure is required by the Windows Form Designer
    ‘It can be modified using the Windows Form Designer. 
    ‘Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Dim resources As System.ComponentModel.ComponentResourceManager = New System.ComponentModel.ComponentResourceManager(GetType(frmMainPolar))
        Me.grphPolar = New Xceed.Chart.ChartControl
        Me.txtFrequency = New System.Windows.Forms.TextBox
        Me.Label1 = New System.Windows.Forms.Label
        Me.cmdStart = New System.Windows.Forms.Button
        Me.cmdClose = New System.Windows.Forms.Button
        Me.cmbFreqUnits = New System.Windows.Forms.ComboBox
        Me.cmbSpanUnits = New System.Windows.Forms.ComboBox
        Me.Label2 = New System.Windows.Forms.Label
        Me.txtSpan = New System.Windows.Forms.TextBox
        Me.cmdSaveGraph = New System.Windows.Forms.Button
        Me.numSweepTime = New System.Windows.Forms.NumericUpDown
        Me.Label3 = New System.Windows.Forms.Label
        Me.Label4 = New System.Windows.Forms.Label
        Me.txtAntennaHeight = New System.Windows.Forms.TextBox
        Me.Label5 = New System.Windows.Forms.Label
        CType(Me.numSweepTime, System.ComponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        ‘
        ‘grphPolar
        ‘
        Me.grphPolar.BackColor = System.Drawing.SystemColors.Control
        Me.grphPolar.Background = CType(resources.GetObject(“grphPolar.Background”), Xceed.Chart.Standard.Background)
        Me.grphPolar.Charts = CType(resources.GetObject(“grphPolar.Charts”), Xceed.Chart.Core.ChartCollection)
        Me.grphPolar.InteractivityOperations = CType(resources.GetObject(“grphPolar.InteractivityOperations”), Xceed.Chart.Core.InteractivityOperationsCollection)
        Me.grphPolar.Labels = CType(resources.GetObject(“grphPolar.Labels”), Xceed.Chart.Standard.ChartLabelCollection)
        Me.grphPolar.Legends = CType(resources.GetObject(“grphPolar.Legends”), Xceed.Chart.Core.LegendCollection)
        Me.grphPolar.Location = New System.Drawing.Point(10, 13)
        Me.grphPolar.Margin = New System.Windows.Forms.Padding(5)
        Me.grphPolar.Name = “grphPolar”
        Me.grphPolar.Settings = CType(resources.GetObject(“grphPolar.Settings”), Xceed.Chart.Core.Settings)
        Me.grphPolar.Size = New System.Drawing.Size(700, 600)
        Me.grphPolar.TabIndex = 0
        Me.grphPolar.Text = “grphPolar”
        Me.grphPolar.Watermarks = CType(resources.GetObject(“grphPolar.Watermarks”), Xceed.Chart.Standard.WatermarkCollection)
        ‘
        ‘txtFrequency
        ‘
        Me.txtFrequency.Location = New System.Drawing.Point(822, 18)
        Me.txtFrequency.Margin = New System.Windows.Forms.Padding(5)
        Me.txtFrequency.Name = “txtFrequency”
        Me.txtFrequency.Size = New System.Drawing.Size(101, 26)
        Me.txtFrequency.TabIndex = 1
        Me.txtFrequency.Text = “2450”
        Me.txtFrequency.TextAlign = System.Windows.Forms.HorizontalAlignment.Right
        ‘
        ‘Label1
        ‘
        Me.Label1.AutoSize = True
        Me.Label1.Location = New System.Drawing.Point(721, 21)
        Me.Label1.Name = “Label1”
        Me.Label1.Size = New System.Drawing.Size(93, 20)
        Me.Label1.TabIndex = 2
        Me.Label1.Text = “Frequency”
        ‘
        ‘cmdStart
        ‘
        Me.cmdStart.Font = New System.Drawing.Font(“Microsoft Sans Serif”, 14.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.cmdStart.ForeColor = System.Drawing.Color.Green
        Me.cmdStart.Location = New System.Drawing.Point(844, 239)
        Me.cmdStart.Name = “cmdStart”
        Me.cmdStart.Size = New System.Drawing.Size(160, 116)
        Me.cmdStart.TabIndex = 4
        Me.cmdStart.Text = “Start”
        Me.cmdStart.UseVisualStyleBackColor = True
        ‘
        ‘cmdClose
        ‘
        Me.cmdClose.DialogResult = System.Windows.Forms.DialogResult.Cancel
        Me.cmdClose.Font = New System.Drawing.Font(“Microsoft Sans Serif”, 14.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.cmdClose.ForeColor = System.Drawing.Color.Red
        Me.cmdClose.Location = New System.Drawing.Point(844, 659)
        Me.cmdClose.Name = “cmdClose”
        Me.cmdClose.Size = New System.Drawing.Size(160, 63)
        Me.cmdClose.TabIndex = 5
        Me.cmdClose.Text = “CLOSE”
        Me.cmdClose.UseVisualStyleBackColor = True
        ‘
        ‘cmbFreqUnits
        ‘
        Me.cmbFreqUnits.Items.AddRange(New Object() {“Hz”, “KHz”, “MHz”})
        Me.cmbFreqUnits.Location = New System.Drawing.Point(926, 18)
        Me.cmbFreqUnits.Name = “cmbFreqUnits”
        Me.cmbFreqUnits.Size = New System.Drawing.Size(72, 28)
        Me.cmbFreqUnits.TabIndex = 54
        Me.cmbFreqUnits.Text = “MHz”
        ‘
        ‘cmbSpanUnits
        ‘
        Me.cmbSpanUnits.Items.AddRange(New Object() {“Hz”, “KHz”, “MHz”})
        Me.cmbSpanUnits.Location = New System.Drawing.Point(926, 54)
        Me.cmbSpanUnits.Name = “cmbSpanUnits”
        Me.cmbSpanUnits.Size = New System.Drawing.Size(72, 28)
        Me.cmbSpanUnits.TabIndex = 57
        Me.cmbSpanUnits.Text = “KHz”
        ‘
        ‘Label2
        ‘
        Me.Label2.AutoSize = True
        Me.Label2.Location = New System.Drawing.Point(721, 57)
        Me.Label2.Name = “Label2”
        Me.Label2.Size = New System.Drawing.Size(51, 20)
        Me.Label2.TabIndex = 56
        Me.Label2.Text = “Span”
        ‘
        ‘txtSpan
        ‘
        Me.txtSpan.Location = New System.Drawing.Point(822, 54)
        Me.txtSpan.Margin = New System.Windows.Forms.Padding(5)
        Me.txtSpan.Name = “txtSpan”
        Me.txtSpan.Size = New System.Drawing.Size(101, 26)
        Me.txtSpan.TabIndex = 55
        Me.txtSpan.Text = “500”
        Me.txtSpan.TextAlign = System.Windows.Forms.HorizontalAlignment.Right
        ‘
        ‘cmdSaveGraph
        ‘
        Me.cmdSaveGraph.ForeColor = System.Drawing.Color.Green
        Me.cmdSaveGraph.Location = New System.Drawing.Point(564, 621)
        Me.cmdSaveGraph.Name = “cmdSaveGraph”
        Me.cmdSaveGraph.Size = New System.Drawing.Size(146, 49)
        Me.cmdSaveGraph.TabIndex = 58
        Me.cmdSaveGraph.Text = “Save Graph”
        Me.cmdSaveGraph.UseVisualStyleBackColor = True
        ‘
        ‘numSweepTime
        ‘
        Me.numSweepTime.Location = New System.Drawing.Point(822, 89)
        Me.numSweepTime.Maximum = New Decimal(New Integer() {5000, 0, 0, 0})
        Me.numSweepTime.Minimum = New Decimal(New Integer() {20, 0, 0, 0})
        Me.numSweepTime.Name = “numSweepTime”
        Me.numSweepTime.Size = New System.Drawing.Size(101, 26)
        Me.numSweepTime.TabIndex = 59
        Me.numSweepTime.TextAlign = System.Windows.Forms.HorizontalAlignment.Right
        Me.numSweepTime.Value = New Decimal(New Integer() {20, 0, 0, 0})
        ‘
        ‘Label3
        ‘
        Me.Label3.AutoSize = True
        Me.Label3.Location = New System.Drawing.Point(721, 91)
        Me.Label3.Name = “Label3”
        Me.Label3.Size = New System.Drawing.Size(97, 20)
        Me.Label3.TabIndex = 60
        Me.Label3.Text = “Sweeptime”
        ‘
        ‘Label4
        ‘
        Me.Label4.AutoSize = True
        Me.Label4.Location = New System.Drawing.Point(923, 91)
        Me.Label4.Name = “Label4”
        Me.Label4.Size = New System.Drawing.Size(32, 20)
        Me.Label4.TabIndex = 61
        Me.Label4.Text = “ms”
        ‘
        ‘txtAntennaHeight
        ‘
        Me.txtAntennaHeight.Location = New System.Drawing.Point(822, 122)
        Me.txtAntennaHeight.Name = “txtAntennaHeight”
        Me.txtAntennaHeight.Size = New System.Drawing.Size(100, 26)
        Me.txtAntennaHeight.TabIndex = 62
        ‘
        ‘Label5
        ‘
        Me.Label5.Location = New System.Drawing.Point(721, 116)
        Me.Label5.Name = “Label5”
        Me.Label5.Size = New System.Drawing.Size(78, 41)
        Me.Label5.TabIndex = 63
        Me.Label5.Text = “Antenna Height”
        ‘
        ‘frmMainPolar
        ‘
        Me.AutoScaleDimensions = New System.Drawing.SizeF(10.0!, 20.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(1016, 734)
        Me.Controls.Add(Me.Label5)
        Me.Controls.Add(Me.txtAntennaHeight)
        Me.Controls.Add(Me.Label4)
        Me.Controls.Add(Me.Label3)
        Me.Controls.Add(Me.numSweepTime)
        Me.Controls.Add(Me.cmdSaveGraph)
        Me.Controls.Add(Me.cmbSpanUnits)
        Me.Controls.Add(Me.Label2)
        Me.Controls.Add(Me.txtSpan)
        Me.Controls.Add(Me.cmbFreqUnits)
        Me.Controls.Add(Me.cmdClose)
        Me.Controls.Add(Me.cmdStart)
        Me.Controls.Add(Me.Label1)
        Me.Controls.Add(Me.txtFrequency)
        Me.Controls.Add(Me.grphPolar)
        Me.Font = New System.Drawing.Font(“Microsoft Sans Serif”, 12.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Margin = New System.Windows.Forms.Padding(5)
        Me.Name = “frmMainPolar”
        Me.StartPosition = System.Windows.Forms.FormStartPosition.Manual
        Me.Text = “Polar Capture and Plot”
        CType(Me.numSweepTime, System.ComponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)
        Me.PerformLayout()

    End Sub
    Friend WithEvents grphPolar As Xceed.Chart.ChartControl
    Friend WithEvents txtFrequency As System.Windows.Forms.TextBox
    Friend WithEvents Label1 As System.Windows.Forms.Label
    Friend WithEvents cmdStart As System.Windows.Forms.Button
    Friend WithEvents cmdClose As System.Windows.Forms.Button
    Friend WithEvents cmbFreqUnits As System.Windows.Forms.ComboBox
    Friend WithEvents cmbSpanUnits As System.Windows.Forms.ComboBox
    Friend WithEvents Label2 As System.Windows.Forms.Label
    Friend WithEvents txtSpan As System.Windows.Forms.TextBox
    Friend WithEvents cmdSaveGraph As System.Windows.Forms.Button
    Friend WithEvents numSweepTime As System.Windows.Forms.NumericUpDown
    Friend WithEvents Label3 As System.Windows.Forms.Label
    Friend WithEvents Label4 As System.Windows.Forms.Label
    Friend WithEvents txtAntennaHeight As System.Windows.Forms.TextBox
    Friend WithEvents Label5 As System.Windows.Forms.Label
End Class

 

frmmainPolar.vb———————————————————————————

 Imports Xceed.Chart.Core
Imports Xceed.Chart.GraphicsCore
Imports System.threading

Public Class frmMainPolar

    Private Const iReadInterval As Integer = 500     ‘ no of milliseconds between readings
    Dim bStopSweep As Boolean

    Private Sub txtFrequency_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtFrequency.Click

        Dim f As frmKeypad

        If gTouchScreen Then
            f = New frmKeypad
            f.sEntryType = “Frequency”
            f.txtUnit.Text = cmbFreqUnits.Text
            If f.ShowDialog = Windows.Forms.DialogResult.OK Then
                txtFrequency.Text = f.txtNumber.Text
                cmbFreqUnits.Text = f.txtUnit.Text
            End If
        End If

    End Sub

    Private Sub cmdStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdStart.Click

        Dim iFreq As Double, iSpan As Double, iAngle As Single, iStep As Single, iAmplitude As Single
        Dim ps As PolarSeries
        Dim i As Integer

        If cmdStart.Text = “Stop” Then
            bStopSweep = True
            Exit Sub
        End If

        iFreq = Val(txtFrequency.Text)
        If cmbFreqUnits.Text = “KHz” Then iFreq *= 1000
        If cmbFreqUnits.Text = “MHz” Then iFreq *= 1000000
        iSpan = Val(txtSpan.Text)
        If cmbSpanUnits.Text = “KHz” Then iSpan *= 1000
        If cmbSpanUnits.Text = “MHz” Then iSpan *= 1000000

        gMyAnalyser.SweepSingle()
        gMyAnalyser.CentreFrequency = Val(iFreq)
        gMyAnalyser.Span = iSpan
        gMyAnalyser.SweepTime = numSweepTime.Value
        gMyAnalyser.MarkerOn()
        gMyAnalyser.MarkerNormal()
        gMyAnalyser.TakeSweep()
        gMyAnalyser.MarkerToHighestPeak()
        gMyAnalyser.TakeSweep()
        gMyAnalyser.MarkerToCentreFrequency()
        gMyAnalyser.TakeSweep()
        gMyAnalyser.MarkerToHighestPeak()
        gMyAnalyser.SweepContinuous()

        If MsgBox(“Analyser is ready: click OK when ready to start sweep, or Cancel to stop now.”, MsgBoxStyle.OkCancel + MsgBoxStyle.Information, “EMC Lab”) = MsgBoxResult.Cancel Then Exit Sub

        ps = grphPolar.Charts(0).Series(0)  ‘ get the polar series
        ps.Values.Clear()
        ps.Angles.Clear()
        bStopSweep = False

        cmdStart.Text = “Stop”

        Do
            iAmplitude = gMyAnalyser.GetMarkerAmplitude()
            ps.AddPolar(iAmplitude, 0)
            Application.DoEvents()
        Loop Until bStopSweep

        Beep()
        MsgBox(“Sweep Complete: ” & ps.Values.Count & ” readings taken”, MsgBoxStyle.Information, “EMCLab”)
        cmdStart.Text = “Start”
        cmdSaveGraph.ForeColor = Color.Red

        ‘ Distribute the readings around the 360 degrees of the graph
        iStep = 360 / ps.Values.Count
        iAngle = 0
        For i = 0 To ps.Values.Count – 1
            ps.Angles(i) = iAngle
            iAngle += iStep
        Next
        grphPolar.Refresh()

    End Sub

    Private Sub frmMainPolar_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing

        If cmdSaveGraph.ForeColor = Color.Red Then
            If MsgBox(“Graph is not saved: do you want to save it before closing?”, MsgBoxStyle.Question + MsgBoxStyle.YesNo + MsgBoxStyle.DefaultButton1, “EMCLab”) = MsgBoxResult.Yes Then cmdSaveGraph_Click(cmdSaveGraph, e)
        End If

    End Sub

    Private Sub frmMainPolar_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim f As frmSelectInstrument

        If gMyAnalyser Is Nothing Then
            f = New frmSelectInstrument
            f.sClass = “CR”
            If f.ShowDialog = Windows.Forms.DialogResult.Cancel Then
                Close()
                Exit Sub
            End If
        End If

        If Not gFlashDrivePresent Then cmdSaveGraph.Enabled = False

    End Sub

    Private Sub txtSpan_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtSpan.Click

        Dim f As frmKeypad

        If gTouchScreen Then
            f = New frmKeypad
            f.sEntryType = “Frequency”
            f.txtUnit.Text = cmbSpanUnits.Text
            If f.ShowDialog = Windows.Forms.DialogResult.OK Then
                txtSpan.Text = f.txtNumber.Text
                cmbSpanUnits.Text = f.txtUnit.Text
            End If
        End If

    End Sub

    Private Sub cmdSaveGraph_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSaveGraph.Click

        Dim f As New frmSaveImage

        f.CategoryChanged(f.optOther, e)
        If f.ShowDialog() = Windows.Forms.DialogResult.OK Then
            SaveImageWithAnnotation(grphPolar, f, False)
            If gFlashDrivePresent Then myJob.IncrementGraphNumber()
            cmdSaveGraph.ForeColor = Color.Green
        End If

    End Sub

End Class

Imported from legacy forums. Posted by Steve (had 2179 views)

[User (Old forums)]

#19106

You must make sure the chart itself is a perfect square, so that polar series draws as a perfect circle.  If not, the circle will be skewed, as an ellipse.  To accomplish that, you need to set the width and height of the chart to the same value.

e.g.:

  Dim chart As Chart = grphPolar.Charts(0)
  chart.Width = 70.0f;
  chart.Height = 70.0f;

 

Imported from legacy forums. Posted by André (had 369 views)

[User (Old forums)]

#19107

Many thanks Andre – so obvious when you know!  I tried to size it using the MarginMode and margins, but clearly ended up with skewed sizing in the X and Y directions.  Didn’t notice that.  I do find the sizing of charts unnecessarily confusing – but that’s another story.  Anyway, this problem solved, thanks again.

Imported from legacy forums. Posted by Steve (had 3378 views)

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