Processing records using Haversine Formula in c#

Posted on 2009-07-09
Last Modified: 2013-12-17
I am new to c# and need to write a program that will process GPS postion data from a sql server database and then calculate the total distance traveled for each unit listed by date.  Each record contains a transaction id,  date/time stamp, unit id, latitude and longitude. I have bound this table to a dataset.  I also  have a class for the haversine formula which will accepts the fields LAT (A) LON (A), LAT(B), LON (B).  Where I am stuck is how to process the data from the data set (Keeping in mind that the data needs to be read one record at a time) and then loop through the records, apply the haversine formula then subtotal by unit and date.  The final step would be to insert a record into a new table that contains the Equipment ID, Date, and total miles .   Attached is the class I plan to use and sample data.    Any suggestions would be greatly appreciated.  
Question by:maximjon
LVL 15

Accepted Solution

spprivate earned 500 total points
ID: 24818604

Author Comment

ID: 25026098
This was a lot easier than I initially though.  After I setup a SQLconnection, I wrote my code to loop through the SQLdataReader one record at a time.  I simply just setup variables to retain all important info from each record (see code below)
Dim dr As SqlDataReader = myCommand.ExecuteReader()

            lngRecordCount = 1

            While dr.Read()

                If lngRecordCount > 1 Then

                    strEquipID = dr(0)

                    strInsertDate = DateValue(dr(1))

                    dblLat2 = dr(2)

                    dblLon2 = dr(3)

                    ' compare the Equipment ID and InsertDate of the two records to see if they changed.  Reset All variables and start over if they did.

                    If strPriorEquipID <> strEquipID Or strPriorInsertDate <> strInsertDate Then

                        'Write the prior equipID......

                        ' This IF statement is a temporary work around for faulty data.  Lat & Lon need to have a decimal else the haversine brings back bad data

                        If totalDistance >= 0 Then

                            myCommandWrite = New SqlCommand("INSERT INTO tblSalOutput VALUES ('" & strPriorEquipID & "', '" & strPriorInsertDate & "', " & totalDistance & ",'" & strBranch & "')", myConnectionWrite)

                            ra = myCommandWrite.ExecuteNonQuery()

                            '   MessageBox.Show("New Row Inserted" & ra)

                        End If

                        lngRecordCount = 1

                        totalDistance = 0


                        ' Now that you have lat1-lat2 & lon1-lon2, apply your formula here and write back to a serpare table

                        tmpDistance = distance(dblLat1, dblLon1, dblLat2, dblLon2)

                        totalDistance = totalDistance + tmpDistance

                    End If

                End If

                strPriorEquipID = dr(0)

                strPriorInsertDate = DateValue(dr(1))

                dblLat1 = dr(2)

                dblLon1 = dr(3)

                strBranch = dr(4)

                lngRecordCount = lngRecordCount + 1

            End While

    Public Function distance(ByVal lat1 As Double, ByVal lon1 As Double, _

                         ByVal lat2 As Double, ByVal lon2 As Double, _

                         Optional ByVal unit As Char = "M"c) As Double

        Dim theta As Double = lon1 - lon2

        Dim dist As Double = Math.Sin(deg2rad(lat1)) * Math.Sin(deg2rad(lat2)) + _

                                Math.Cos(deg2rad(lat1)) * Math.Cos(deg2rad(lat2)) * _


        dist = Math.Acos(dist)

        dist = rad2deg(dist)

        dist = dist * 60 * 1.1515

        If unit = "K" Then

            dist = dist * 1.609344

        ElseIf unit = "N" Then

            dist = dist * 0.8684

        End If

        Return dist

    End Function

    Public Function Haversine(ByVal lat1 As Double, ByVal lon1 As Double, _

                             ByVal lat2 As Double, ByVal lon2 As Double, _

                             Optional ByVal unit As Char = "M"c) As Double

        Dim R As Double = 6371 'earth radius in km

        Dim dLat As Double

        Dim dLon As Double

        Dim a As Double

        Dim c As Double

        Dim d As Double

        dLat = deg2rad(lat2 - lat1)

        dLon = deg2rad((lon2 - lon1))

        a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) + Math.Cos(deg2rad(lat1)) * _

                Math.Cos(deg2rad(lat2)) * Math.Sin(dLon / 2) * Math.Sin(dLon / 2)

        c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a))

        d = R * c

        Select Case unit.ToString.ToUpper

            Case "M"c

                d = d * 0.62137119

            Case "N"c

                d = d * 0.5399568

        End Select

        Return d

    End Function

    Private Function deg2rad(ByVal deg As Double) As Double

        Return (deg * Math.PI / 180.0)

    End Function

    Private Function rad2deg(ByVal rad As Double) As Double

        Return rad / Math.PI * 180.0

    End Function

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