Android Question Google Direction API

[Walter Adriano da Silva]

Hi,

I wish someone would help me in the following situation...

In my project I'm using Google Direction API to return me a route between two points, this comes back in JSON format (Exemple Here). Handle JSON with this code:

Sub traceRoute(JSON As String)
    Dim parser As JSONParser
    parser.Initialize(JSON)
    Dim root As Map = parser.NextObject
    If root.Get("status") = "OK" Then
        Dim routes As List = root.Get("routes")
        For Each colroutes As Map In routes
            Dim bounds As Map = colroutes.Get("bounds")
       
            Dim southwest As Map = bounds.Get("southwest")
            Dim swlat As Double = southwest.Get("lat")
            Dim swlng As Double = southwest.Get("lng")
            Dim sw As LatLng
            sw.Initialize(swlat, swlng)
       
            Dim northeast As Map = bounds.Get("northeast")
            Dim nelat As Double = northeast.Get("lat")
            Dim nelng As Double = northeast.Get("lng")
            Dim ne As LatLng
            ne.Initialize(nelat, nelng)
            Dim posBounds As LatLngBounds
            posBounds.Initialize(sw, ne)
            SetZoom(100, posBounds)
                   
            Dim sb As StringBuilder
            sb.Initialize
            Dim listPoly As List
            listPoly.Initialize
            Dim legs As List = colroutes.Get("legs")
            For Each collegs As Map In legs
                Dim steps As List = collegs.Get("steps")
                For Each colsteps As Map In steps
                    Dim polylineMap As Map = colsteps.Get("polyline")
                    sb.Append(polylineMap.Get("points"))
                Next
            Next
       
            listPoly.AddAll(decodePoly(sb.ToString))
       
            polyRoute = gmap.AddPolyline
            polyRoute.Color = Colors.RGB(255, 241, 89)
       
            polyRoute.Points = listPoly
            For i = 0 To listPoly.Size - 1
                Log("ListPoly: " & listPoly.Get(i))
            Next
            listPoly.Clear
        Next
    Else
        Log("Status: " & root.Get("status"))
    End If

End Sub

I get the "points" insides of the"polylines" of "steps" and points are decoded with the following code:

Sub decodePoly(encoded As String) As List
    Dim poly As List
    poly.Initialize
    Dim index, len As Int : index = 0 : len = encoded.Length
    Dim lat, lng As Int : lat = 0 : lng = 0

    Do While index < len
        Dim b, b1, shift, result As Int : shift = 0 : result = 0 : b = 0x21
   
        Do While (b >= 0x20)
            Dim bytes() As Byte
            Dim s As String
            s = encoded.CharAt(index)
            bytes = s.GetBytes("UTF8")
            b = bytes(0)
            b = b - 63
            b1 = Bit.AND(b, 0x1f)
            b1 = Bit.ShiftLeft(b1, shift)
            result = Bit.OR(result, b1)
            shift = shift + 5
            index = index + 1
        Loop
   
        Dim dlat As Int
        result = Bit.ShiftRight(result, 1)
        If Bit.AND(result, 1) <> 0 Then
            dlat = Bit.Not(result)
        Else
            dlat = result
        End If
        lat = lat + dlat
   
        If(index = encoded.Length) Then
            Exit
        End If
   
        b = 0x21
        shift = 0
        result = 0
        Do While (b >= 0x20)
            Dim bytes() As Byte
            Dim s As String
            s = encoded.CharAt(index)
            bytes = s.GetBytes("UTF8")
            b = bytes(0)
            b = b - 63
            b1 = Bit.AND(b, 0x1f)
            b1 = Bit.ShiftLeft(b1, shift)
            result = Bit.OR(result, b1)
            shift = shift + 5
            index = index + 1
        Loop
   
        Dim dlng As Int
        result = Bit.ShiftRight(result, 1)
        If Bit.AND(result, 1) <> 0 Then
            dlng = Bit.Not(result)
        Else
            dlng = result
        End If
        lng = lng + dlng
   
        Dim p As LatLng
        p.Initialize(lat / 1E5, lng / 1E5)
        poly.Add(p)
       
    Loop
   
    Return poly
End Sub

And if I use the coordinates shown in the example, the log returns me:

ListPoly: lat/lng: (23.54596,-46.6388)
ListPoly: lat/lng: (23.5459,-46.63888)
ListPoly: lat/lng: (23.54592,-46.6389)
ListPoly: lat/lng: (23.54586,-46.63896)
ListPoly: lat/lng: (23.5458,-46.6389)
ListPoly: lat/lng: (23.54594,-46.63876)
ListPoly: lat/lng: (23.54596,-46.63878)
ListPoly: lat/lng: (23.546,-46.6388)
ListPoly: lat/lng: (23.54596,-46.6388)
ListPoly: lat/lng: (23.54592,-46.6388)
ListPoly: lat/lng: (23.54594,-46.63882)
ListPoly: lat/lng: (23.54596,-46.63882)
ListPoly: lat/lng: (23.546,-46.63886)
ListPoly: lat/lng: (23.54598,-46.63888)
ListPoly: lat/lng: (23.546,-46.6389)
ListPoly: lat/lng: (23.54586,-46.6388)
ListPoly: lat/lng: (23.54592,-46.63886)
ListPoly: lat/lng: (23.546,-46.63894)
ListPoly: lat/lng: (23.54574,-46.63914)
ListPoly: lat/lng: (23.54584,-46.63922)
ListPoly: lat/lng: (23.54572,-46.6393)
ListPoly: lat/lng: (0.00102,-93.27792)
ListPoly: lat/lng: (0.0012,-93.2778)
ListPoly: lat/lng: (8.2E-4,-93.27758)
ListPoly: lat/lng: (4.4E-4,-93.27782)
ListPoly: lat/lng: (4.0E-4,-93.2778)
ListPoly: lat/lng: (4.2E-4,-93.2778)
ListPoly: lat/lng: (4.4E-4,-93.2778)
ListPoly: lat/lng: (4.2E-4,-93.2778)

And these coordinates are incorrect.
Can anyone help me?

Regards.

PS: Sorry for my english

Edit:

A sample of how I used the Direction API

 

[rboeck]

I have stored this routine; this was published at this forum:

Try this code:

Sub MapsDecodePolyline(encoded As String, poly As List)
    Log("MapsDecodePolyline")
 
    Dim index As Int
    Dim lat As Int
    Dim lng As Int
    Dim fLat As Float
    Dim fLng As Float
    Dim b As Int
    Dim shift As Int
    Dim result As Int
    Dim dlat As Int
    Dim dlng As Int
    Dim p As LatLng
    Dim i As Int
    Dim l As LatLng

    index = 0 : lat = 0 : lng = 0
    Do While index < encoded.Length
        shift = 0 : result = 0
        Do While True
            b = Asc(encoded.SubString2(index, index + 1)) - 63 : index = index + 1
            result = Bit.OR(result, Bit.ShiftLeft(Bit.AND(b, 0x1f), shift))
            shift = shift + 5
            If b < 0x20 Then Exit
        Loop
     
        If Bit.AND(result, 1) = 1 Then
            dlat = Bit.Not(Bit.ShiftRight(result, 1))
        Else
            dlat = Bit.ShiftRight(result, 1)
        End If
        lat = lat + dlat
        shift = 0 : result = 0
        Do While True
            b = Asc(encoded.SubString2(index, index + 1)) - 63 : index = index + 1
            result = Bit.OR(result, Bit.ShiftLeft(Bit.AND(b, 0x1f), shift))
            shift = shift + 5
            If b < 0x20 Then Exit
        Loop
     
        If Bit.AND(result, 1) = 1 Then
            dlng = Bit.Not(Bit.ShiftRight(result, 1))
        Else
            dlng = Bit.ShiftRight(result, 1)
        End If
        lng = lng + dlng
        fLat = lat
        fLng = lng
     
        Dim mpiCurrent As MapsPointItem
        mpiCurrent.Initialize
        mpiCurrent.iPassed = 0
        mpiCurrent.dLatitude = fLat / 100000
        mpiCurrent.dLongitude = fLng / 100000
        poly.add(mpiCurrent)
    Loop
End Sub