Mapping with a GPS and VB.NET

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Text
Imports System.Windows.Forms
Imports System.IO.Ports


Public Class frmPP


#Region "Member Variables"

    ' Local variables used to hold the present
    ' position as latitude and longitude
    Public Latitude As String
    Public Longitude As String

#End Region



#Region "Constructor"


    Public Sub New()

        ' This call is required by the Windows Form Designer.
        InitializeComponent()

        ' Try to open the serial port
        Try
            SerialPort1.Open()
        Catch ex As Exception
            MessageBox.Show(ex.Message)
            timer1.Enabled = False
            btnUpdate.Text = "Update"
            Return
        End Try

    End Sub


#End Region


    Private Sub timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) _
    Handles timer1.Tick

        If SerialPort1.IsOpen Then

            Dim data As String = SerialPort1.ReadExisting()
            Dim strArr() As String = data.Split("$")
            Dim i As Integer = 0

            If strArr.Length > 1 Then

                Try

                    For i = 0 To strArr.Length

                        Dim strTemp As String = strArr(i)
                        Dim lineArr() As String = strTemp.Split(",")

                        If (lineArr(0) = "GPGGA") Then

                            Try

                                ' Latitude
                                Dim dLat As Double = Convert.ToDouble(lineArr(2))
                                dLat = dLat / 100
                                Dim lat() As String = dLat.ToString().Split(".")
                                Latitude = lineArr(3).ToString() + lat(0).ToString() + _
                                "." + ((Convert.ToDouble(lat(1)) / 60)).ToString("#####")

                                ' Longitude
                                Dim dLon As Double = Convert.ToDouble(lineArr(4))
                                dLon = dLon / 100
                                Dim lon() As String = dLon.ToString().Split(".")
                                Longitude = lineArr(5).ToString() + lon(0).ToString() + _
                                "." + ((Convert.ToDouble(lon(1)) / 60)).ToString("#####")

                                ' Display
                                txtLat.Text = Latitude
                                txtLong.Text = Longitude

                                btnMapIt.Enabled = True

                            Catch

                                ' Can't Read GPS values
                                txtLat.Text = "GPS Unavailable"
                                txtLong.Text = "GPS Unavailable"
                                btnMapIt.Enabled = False

                            End Try

                        End If

                    Next

                Catch
                    'do nothing
                End Try

            End If

        Else

            txtLat.Text = "COM Port Closed"
            txtLong.Text = "COM Port Closed"
            btnMapIt.Enabled = False

        End If

    End Sub



    Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpdate.Click

        ' cycle timer
        If timer1.Enabled = True Then
            timer1.Enabled = False
        Else
            timer1.Enabled = True
        End If

        ' update button label
        If btnUpdate.Text = "Update" Then
            btnUpdate.Text = "Stop Updates"
        Else
            btnUpdate.Text = "Update"
        End If

    End Sub


    Private Sub exitToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exitToolStripMenuItem.Click

        Application.Exit()

    End Sub


    Private Sub toolStripMenuItem2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles toolStripMenuItem2.Click

        Try
            SerialPort1.Close()
            SerialPort1.PortName = "COM1"
            SerialPort1.Open()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "COM1")
        End Try

    End Sub



    Private Sub toolStripMenuItem3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles toolStripMenuItem3.Click

        Try
            SerialPort1.Close()
            SerialPort1.PortName = "COM2"
            SerialPort1.Open()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "COM2")
        End Try

    End Sub



    Private Sub toolStripMenuItem4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles toolStripMenuItem4.Click

        Try
            SerialPort1.Close()
            SerialPort1.PortName = "COM3"
            SerialPort1.Open()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "COM3")
        End Try

    End Sub



    Private Sub toolStripMenuItem5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles toolStripMenuItem5.Click

        Try
            SerialPort1.Close()
            SerialPort1.PortName = "COM4"
            SerialPort1.Open()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "COM4")
        End Try

    End Sub



    Private Sub toolStripMenuItem6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles toolStripMenuItem6.Click

        Try
            SerialPort1.Close()
            SerialPort1.PortName = "COM5"
            SerialPort1.Open()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "COM5")
        End Try

    End Sub



    Private Sub btnMapIt_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnMapIt.Click

        If Latitude <> String.Empty And Longitude <> String.Empty Then

            Dim f As New frmMap(Latitude, Longitude)
            f.Show()

        End If

    End Sub




End Class