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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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