How to get GLatLng object from address string in advance in google maps? - latitude-longitude

Question

I want to get latlng object in google maps in advance. Basically my json result is returning array of address which I need to convert to glatlng to use for markers. But if i will use GeoCoder object then it will send asynch request which I don't want.
Is there any way other than GeoCoder object to convert an address string to GLatLng object?

Answer 1

You can take a look at the json object returned by any query to the maps api.
Then you use the json serializer in system.web.extensions to serialize the json into a class that you have to create from the JSONresponses which you analyze manually.
Note that you can get localized language return results by adding this to the http web request:
wrHTTPrequest.UserAgent = "Lord Vishnu/Transcendental (Vaikuntha;Supreme Personality of Godness)"
wrHTTPrequest.Headers.Add("Accept-Language:" + System.Globalization.CultureInfo.CurrentCulture.Name)
wrHTTPrequest.ContentType = "text/html"
Edit:
The example, from one of my files (remove all the SharpMap.Map stuff, it requires an external assembly.
Copyright (C) 2010 Me. Permission is hereby granted to use it for
good, not evil - if you add me to your thanks list.
Public Class _Default
Inherits System.Web.UI.Page
Protected smmGlobalMap As SharpMap.Map
'http://www.java2s.com/Code/VB/Development/ListallCultureInformation.htm
Public Sub listcultures()
'Dim x As System.DateTime = DateTime.Now
'Response.Write(x.ToString("HH':'mm':'ss MMM d', 'yyyy 'PST'", New System.Globalization.CultureInfo("zh-CN", False)))
Dim info As System.Globalization.CultureInfo
For Each info In System.Globalization.CultureInfo.GetCultures(System.Globalization.CultureTypes.AllCultures)
Response.Write("Deutsch: " + info.DisplayName + " English: " + info.EnglishName + " Native: " + info.NativeName + " Name: " + info.Name + " Codepage: " + info.TextInfo.ANSICodePage.ToString() + "<br />")
If Not info.IsNeutralCulture Then
'item.SubItems.Add(amount.ToString("C", info.NumberFormat))
'item.SubItems.Add(dateNow.ToString("d", info.DateTimeFormat))
End If
Next
End Sub
Public Sub GeoCodeTest()
'Dim GeoCodeResponse As Google.Maps.JSON.cGeoCodeResponse = GetJSONgeodata("San Bernardino, Switzerland")
'Dim GeoCodeResponse As Google.Maps.JSON.cGeoCodeResponse = GetJSONgeodata("北京")
'Dim GeoCodeResponse As Google.Maps.JSON.cGeoCodeResponse = GeoCodeRequest("San Bernardino, Switzerland")
Dim GeoCodeResponse As Google.Maps.JSON.cGeoCodeResponse = GeoCodeRequest("北京")
Response.Write(Seri(GeoCodeResponse))
Response.Write("<br /><br /><br />")
Response.Write(GeoCodeResponse.results(0).address_components(0).long_name)
Response.Write("<br /><br />")
Response.Write(GeoCodeResponse.results(0).geometry.location.lat.ToString)
Response.Write("<br />")
Response.Write(GeoCodeResponse.results(0).geometry.location.lng.ToString)
Response.Write("<br /><br /><br />")
Response.Write(GeoCodeResponse.results(0).geometry.viewport.northeast.lat.ToString)
Response.Write("<br />")
Response.Write(GeoCodeResponse.results(0).geometry.viewport.northeast.lng.ToString)
Response.Write("<br /><br /><br />")
End Sub
Public Function Seri(ByRef GeoData As Google.Maps.JSON.cGeoCodeResponse) As String
Dim jssJSONserializer As System.Web.Script.Serialization.JavaScriptSerializer = New System.Web.Script.Serialization.JavaScriptSerializer()
Dim CommentData As New Google.Maps.JSON.cGeoCodeResponse
Dim str As String = jssJSONserializer.Serialize(GeoData)
Return str
End Function
' http://www.codeproject.com/KB/IP/httpwebrequest_response.aspx
' http://www.linuxhowtos.org/C_C++/socket.htm
' http://en.wikipedia.org/wiki/List_of_countries_by_GDP_(PPP)_per_capita
Public Function GeoCodeRequest(ByRef strAddress As String) As Google.Maps.JSON.cGeoCodeResponse
strAddress = System.Web.HttpUtility.UrlEncode(strAddress) ' Add reference to System.Web
Dim strURL As String = "http://maps.google.com/maps/api/geocode/json?address=" + strAddress + "&sensor=false"
' *** Establish the request
Dim wrHTTPrequest As System.Net.HttpWebRequest = DirectCast(System.Net.WebRequest.Create(strURL), System.Net.HttpWebRequest)
' *** Set properties
wrHTTPrequest.Method = "GET"
wrHTTPrequest.Timeout = 10000 ' 10 secs
wrHTTPrequest.UserAgent = "Lord Vishnu/Transcendental (Vaikuntha;Supreme Personality of Godness)"
wrHTTPrequest.Headers.Add("Accept-Language:" + System.Globalization.CultureInfo.CurrentCulture.Name)
wrHTTPrequest.ContentType = "text/html"
' *** Retrieve request info headers
Dim wrHTTPresponse As System.Net.HttpWebResponse = DirectCast(wrHTTPrequest.GetResponse(), System.Net.HttpWebResponse)
' My Windows' default code-Page
Dim enc As System.Text.Encoding = System.Text.Encoding.GetEncoding(1252)
' Google's code-page
enc = System.Text.Encoding.UTF8
Dim srResponseStream As New System.IO.StreamReader(wrHTTPresponse.GetResponseStream(), enc)
Dim strJSONencodedResponse As String = srResponseStream.ReadToEnd()
wrHTTPresponse.Close()
srResponseStream.Close()
If String.IsNullOrEmpty(strJSONencodedResponse) Then
Return Nothing
End If
Dim jssJSONserializer As System.Web.Script.Serialization.JavaScriptSerializer = New System.Web.Script.Serialization.JavaScriptSerializer()
Dim GeoCodeResponse As New Google.Maps.JSON.cGeoCodeResponse
GeoCodeResponse = jssJSONserializer.Deserialize(Of Google.Maps.JSON.cGeoCodeResponse)(strJSONencodedResponse)
Return GeoCodeResponse
End Function
Public Function GetJSONgeodata(ByVal strAddress As String) As Google.Maps.JSON.cGeoCodeResponse
'strAddress = "Zurich, Switzerland"
strAddress = System.Web.HttpUtility.UrlEncode(strAddress) ' Add reference to System.Web
Dim strURL As String = "http://maps.google.com/maps/api/geocode/json?address=" + strAddress + "&sensor=false"
Dim wwwClient As Net.WebClient = Nothing
Dim strJSONtranslatedText As String = Nothing
Try
'http://www.stevetrefethen.com/blog/UsingGoogleMapsforGeocodinginC.aspx
wwwClient = New Net.WebClient()
wwwClient.Encoding = System.Text.Encoding.UTF8
strJSONtranslatedText = wwwClient.DownloadString(strURL)
Catch ex As Exception
MsgBox(ex.Message)
Finally
wwwClient.Dispose()
wwwClient = Nothing
End Try
If String.IsNullOrEmpty(strJSONtranslatedText) Then
Return Nothing
End If
Dim jssJSONserializer As System.Web.Script.Serialization.JavaScriptSerializer = New System.Web.Script.Serialization.JavaScriptSerializer()
Dim GeoCodeRespone As New Google.Maps.JSON.cGeoCodeResponse
GeoCodeRespone = jssJSONserializer.Deserialize(Of Google.Maps.JSON.cGeoCodeResponse)(strJSONtranslatedText)
Return GeoCodeRespone
End Function
' http://sharpmap.codeplex.com/wikipage?title=CustomTheme
' http://sharpmap.codeplex.com/Thread/View.aspx?ThreadId=28205
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'GeoCodeTest()
listcultures()
'Set up the map
smmGlobalMap = InitializeMap(New System.Drawing.Size(CInt(imgMap.Width.Value), CInt(imgMap.Height.Value)))
If Page.IsPostBack Then
'Page is post back. Restore center and zoom-values from viewstate
smmGlobalMap.Center = DirectCast(ViewState("mapCenter"), SharpMap.Geometries.Point)
smmGlobalMap.Zoom = CDbl(ViewState("mapZoom"))
Else
'This is the initial view of the map. Zoom to the extents of the map:
smmGlobalMap.ZoomToExtents()
'Save the current mapcenter and zoom in the viewstate
ViewState.Add("mapCenter", smmGlobalMap.Center)
ViewState.Add("mapZoom", smmGlobalMap.Zoom)
'Create the map
CreateMap()
End If
DistanceAltstRebstein()
End Sub
Protected Sub imgMap_Click(ByVal sender As Object, ByVal e As ImageClickEventArgs)
'Set center of the map to where the client clicked
smmGlobalMap.Center = SharpMap.Utilities.Transform.MapToWorld(New System.Drawing.Point(e.X, e.Y), smmGlobalMap)
'Set zoom value if any of the zoom tools were selected
If rblMapTools.SelectedValue = "0" Then
'Zoom in
smmGlobalMap.Zoom = smmGlobalMap.Zoom * 0.5
ElseIf rblMapTools.SelectedValue = "1" Then
'Zoom out
smmGlobalMap.Zoom = smmGlobalMap.Zoom * 2
End If
'Save the new map's zoom and center in the viewstate
ViewState.Add("mapCenter", smmGlobalMap.Center)
ViewState.Add("mapZoom", smmGlobalMap.Zoom)
'Create the map
CreateMap()
Response.Write("X: " + e.X.ToString + " Y: " + e.Y.ToString + "<br /><br />")
Response.Write("Longitude: " + smmGlobalMap.Center.X.ToString + " Latitude: " + smmGlobalMap.Center.Y.ToString + "<br />")
End Sub
' http://sharpmapv2.googlecode.com/svn/trunk/SharpMap/Rendering/Thematics/CustomTheme.cs
Public Function SetStyle1(ByVal row As SharpMap.Data.FeatureDataRow) As SharpMap.Styles.VectorStyle
Dim vstlStyle1 As SharpMap.Styles.VectorStyle = New SharpMap.Styles.VectorStyle()
vstlStyle1.Enabled = True
vstlStyle1.EnableOutline = True
vstlStyle1.Fill = System.Drawing.Brushes.Yellow
Return vstlStyle1
End Function
'density, countryname
Private Sub InsertData(ByVal strParameter1 As String, ByVal strParameter2 As String)
Dim dbcon As New System.Data.SqlClient.SqlConnection("Data Source=pc-myname\MS_SQL_2005;Initial Catalog=ddb;Integrated Security=SSPI;")
dbcon.Open()
Dim strSQL As String = "IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'dbo.T_SHP_Country') AND type in (N'U'))"
strSQL += "CREATE TABLE T_SHP_Country( "
strSQL += "SHPC_UID uniqueidentifier NULL, "
strSQL += "SHPC_Density int NULL, "
strSQL += "SHPC_CountryName nvarchar(max) NULL "
strSQL += ") ON [PRIMARY] ;"
Dim dbcmdCheckRequirements As New System.Data.SqlClient.SqlCommand(strSQL, dbcon)
dbcmdCheckRequirements.ExecuteNonQuery()
'dbcmdCheckRequirements.CommandText = "DELETE FROM T_SHP_Country"
'dbcmdCheckRequirements.ExecuteNonQuery()
strParameter1 = strParameter1.Replace("'", "''")
strParameter2 = strParameter2.Replace("'", "''")
'strParameter3 = strParameter3.Replace("'", "''")
strSQL = "INSERT INTO T_SHP_Country "
strSQL += "(SHPC_UID, SHPC_Density, SHPC_CountryName)"
strSQL += "VALUES("
strSQL += "'" + System.Guid.NewGuid.ToString() + "', " 'PLZ_UID, uniqueidentifier
strSQL += " '" + strParameter1 + "', " 'PLZ_Name1, nvarchar(max)
strSQL += " '" + strParameter2 + "' " 'PLZ_State, nvarchar(max)
strSQL += ")"
Dim cmd As New System.Data.SqlClient.SqlCommand(strSQL, dbcon)
cmd.ExecuteNonQuery()
dbcon.Close()
End Sub
Public Function SetStyle(ByVal row As SharpMap.Data.FeatureDataRow) As SharpMap.Styles.VectorStyle
Response.Write("")
If False Then
For i As Integer = 0 To row.Table.Columns.Count - 1 Step 1
Response.Write("<br>" + row.Table.Columns(i).ColumnName + "<br>")
Response.Write("<br>" + row("NAME").ToString + ": " + row("POPDENS").ToString + "<br>")
Next i
End If
Try
'InsertData(row("POPDENS").ToString(), row("NAME").ToString())
Dim vstlStyle As SharpMap.Styles.VectorStyle = New SharpMap.Styles.VectorStyle()
Select Case row("POPDENS")
Case 0 To 5
' Add reference to System.Drawing
Dim colCustomColor As System.Drawing.Color = System.Drawing.Color.FromArgb(50, System.Drawing.Color.Gray)
'Dim customColor As System.Drawing.Color = System.Drawing.Color.FromArgb(255, 0, 110, 255)
Dim sbShadowBrush As System.Drawing.SolidBrush = New System.Drawing.SolidBrush(colCustomColor)
vstlStyle.Fill = sbShadowBrush
Case 6 To 9
vstlStyle.Fill = System.Drawing.Brushes.BlanchedAlmond
Case 10 To 25
vstlStyle.Fill = System.Drawing.Brushes.DarkGreen
Case 26 To 50
vstlStyle.Fill = System.Drawing.Brushes.Green
Case 51 To 100
vstlStyle.Fill = System.Drawing.Brushes.YellowGreen
Case 101 To 200
vstlStyle.Fill = System.Drawing.Brushes.Orange
Case 201 To 250
vstlStyle.Fill = System.Drawing.Brushes.DarkOrange
Case 251 To 300
vstlStyle.Fill = System.Drawing.Brushes.OrangeRed
Case 401 To 600
vstlStyle.Fill = System.Drawing.Brushes.Red
Case 601 To 900
vstlStyle.Fill = System.Drawing.Brushes.DarkRed
Case 901 To 1000
vstlStyle.Fill = System.Drawing.Brushes.Crimson
Case Else
vstlStyle.Fill = System.Drawing.Brushes.Pink
End Select
vstlStyle.EnableOutline = True
Dim clCustomPenColor As System.Drawing.Color = System.Drawing.Color.FromArgb(100, 100, 100, 100)
Dim myPen As New System.Drawing.Pen(clCustomPenColor)
myPen.Width = 0.1
'vstlStyle.Outline = System.Drawing.Pens.Black
vstlStyle.Outline = myPen
Return vstlStyle
'If (row("NAME").ToString().StartsWith("S")) Then
' Dim vstlStyle As SharpMap.Styles.VectorStyle = New SharpMap.Styles.VectorStyle()
' vstlStyle.Fill = System.Drawing.Brushes.Yellow
' Return vstlStyle
'Else
' Return Nothing ' Return null which will render the default style
'End If
Catch ex As Exception
Response.Write(ex.Message)
Return Nothing
End Try
End Function
Sub SetThemeForLayerOnMap(ByRef cstCustomTheme As SharpMap.Rendering.Thematics.CustomTheme, ByVal strLayerName As String, ByRef smmMapParameter As SharpMap.Map)
TryCast(smmMapParameter.GetLayerByName(strLayerName), SharpMap.Layers.VectorLayer).Theme = cstCustomTheme
'CType(smmMapParameter.GetLayerByName(strLayerName), SharpMap.Layers.VectorLayer).Theme = cstCustomTheme
End Sub
Sub ReIndex(ByVal strRelativePath As String)
Dim shfShapeFile As New SharpMap.Data.Providers.ShapeFile(Server.MapPath(strRelativePath), True)
ReIndex(shfShapeFile)
End Sub
Sub ReIndex(ByRef shfShapeFile As SharpMap.Data.Providers.ShapeFile)
If shfShapeFile.IsOpen Then
shfShapeFile.RebuildSpatialIndex()
Else
shfShapeFile.Open()
shfShapeFile.RebuildSpatialIndex()
shfShapeFile.Close()
End If
End Sub
Public Function OldDegreesToRadian(ByVal dblDegrees As Double) As Double
Dim dblRadians = dblDegrees * Math.PI / 180.0
Return dblRadians
End Function
Public Sub DistanceAltstRebstein()
'http://www.getlatlon.com/
Dim allat As Double = 47.377894
Dim allong As Double = 9.539833
Dim reblat As Double = 47.399364
Dim reblong As Double = 9.585995
Dim distance As Double = GetDistance(allat, reblat, allong, reblong)
Response.Write("Distance: " + distance.ToString("#,#.000") + " km")
End Sub
'http://www.codeproject.com/KB/cs/distancebetweenlocations.aspx
'http://www.billsternberger.net/asp-net-mvc/latitude-and-longitude-lookup-with-jquery-c-asp-net-mvc/
'http://webcache.googleusercontent.com/search?q=cache:y6AGC8J7zG8J:bryan.reynoldslive.com/post/Latitude2c-Longitude2c-Bearing2c-Cardinal-Direction2c-Distance2c-and-C.aspx+c%23+get+latitude+longitude&cd=2&hl=en&ct=clnk
Public Function GetDistance(ByVal dblLat1 As Double, ByVal dblLat2 As Double, ByVal dblLong1 As Double, ByVal dblLong2 As Double) As Double
' http://itouchmap.com/latlong.html
' http://mathforum.org/library/drmath/sets/select/dm_lat_long.html
' http://stevemorse.org/jcal/latlon.php
' http://en.wikipedia.org/wiki/Atan2
' http://www.movable-type.co.uk/scripts/latlong.html
' Formula:
' R = Earth's radius (mean radius = 6,371km)
' Δlat = lat2− lat1
' Δlong = long2− long1
' a = sin²(Δlat/2) + cos(lat1)*cos(lat2)*sin²(Δlong/2)
' c = 2*atan2(√a, √(1−a))
' d = R*c
dblLat1 = OldDegreesToRadian(dblLat1)
dblLat2 = OldDegreesToRadian(dblLat2)
dblLong1 = OldDegreesToRadian(dblLong1)
dblLong2 = OldDegreesToRadian(dblLong2)
'http://en.wikipedia.org/wiki/Earth_radius#Mean_radii
Dim dblEarthMeanRadius As Double = 6371.009 ' km
Dim dblHalfDeltaLat As Double = (dblLat2 - dblLat1) / 2.0
Dim dblHalfDeltaLong As Double = (dblLong2 - dblLong1) / 2.0
Dim dblTriangleSideA As Double = Math.Sin(dblHalfDeltaLat) * Math.Sin(dblHalfDeltaLat) + _
Math.Cos(dblLat1) * Math.Cos(dblLat2) * _
Math.Sin(dblHalfDeltaLong) * Math.Sin(dblHalfDeltaLong)
Dim dblTriangleSideC As Double = 2 * Math.Atan2(Math.Sqrt(dblTriangleSideA), Math.Sqrt(1 - dblTriangleSideA))
Dim dblDistance As Double = dblEarthMeanRadius * dblTriangleSideC ' in km
Return dblDistance ' in km
' Note for the English: 1 (statute) mile = 1609.344 m = 1.609344 km
' http://en.wikipedia.org/wiki/Mile#Nautical_mile
dblDistance = dblDistance / 1.609344 ' km to statute miles
Return dblDistance ' in statute miles
End Function
''' <summary>
''' Sets up the map, add layers and sets styles
''' </summary>
''' <param name="outputsize">Initiatial size of output image</param>
''' <returns>Map object</returns>
Private Function InitializeMap(ByVal outputsize As System.Drawing.Size) As SharpMap.Map
'Initialize a new map of size 'imagesize'
Dim map As New SharpMap.Map(outputsize)
map.BackColor = Drawing.Color.AliceBlue
'Set up the countries layer
Dim layCountries As New SharpMap.Layers.VectorLayer("Countries")
'Set the datasource to a shapefile in the App_data folder
Dim sfShapeFile1 As New SharpMap.Data.Providers.ShapeFile(Server.MapPath("~\App_data\Countries.shp"), True)
ReIndex(sfShapeFile1)
'Dim x As System.Data.DataColumnCollection = sfShapeFile1.Columns
'For Each y As DataColumn In x
' Response.Write(y.ColumnName)
' Response.Write(y.DataType.ToString())
'
' Next
'x.Item(0).ColumnName
'x.Item(0).DataType.ToString()
layCountries.DataSource = sfShapeFile1
'Set fill-style to green
Dim MyTheme As New SharpMap.Rendering.Thematics.CustomTheme(AddressOf SetStyle)
Dim defaultstyle As SharpMap.Styles.VectorStyle = New SharpMap.Styles.VectorStyle()
defaultstyle.Fill = System.Drawing.Brushes.Gray
MyTheme.DefaultStyle = defaultstyle
layCountries.Theme = MyTheme
layCountries.Style.Fill = New System.Drawing.SolidBrush(System.Drawing.Color.Green)
'Set the polygons to have a black outline
layCountries.Style.Outline = System.Drawing.Pens.Black
layCountries.Style.EnableOutline = True
'Set up a river layer
Dim layRivers As New SharpMap.Layers.VectorLayer("Rivers")
'Set the datasource to a shapefile in the App_data folder
Dim sh2 As New SharpMap.Data.Providers.ShapeFile(Server.MapPath("~\App_data\Rivers.shp"), True)
ReIndex(sh2)
layRivers.DataSource = sh2
'Define a blue 1px wide pen
layRivers.Style.Line = New System.Drawing.Pen(System.Drawing.Color.Blue, 1)
'Dim x As New SharpMap.Rendering.Thematics.IndividualTheme("abc")
'Add the layers to the map object.
'The order we add them in are the order they are drawn, so we add the rivers last to put them on top
map.Layers.Add(layCountries)
map.Layers.Add(layRivers)
Return map
End Function
''' <summary>
''' Creates the map, inserts it into the cache and sets the ImageButton Url
''' </summary>
Private Sub CreateMap()
If smmGlobalMap Is Nothing Then
Response.Write("<h1 style=""color: red;"">smmGlobalMap is NULL !</h1>")
Else
Dim img As System.Drawing.Image = smmGlobalMap.GetMap()
Dim imgID As String = SharpMap.Web.Caching.InsertIntoCache(1, img)
imgMap.ImageUrl = "getmap.aspx?ID=" & HttpUtility.UrlEncode(imgID)
End If
End Sub
End Class
' http://www.4guysfromrolla.com/articles/052610-1.aspx
' http://code.google.com/apis/maps/faq.html
' http://www.billsternberger.net/asp-net-mvc/latitude-and-longitude-lookup-with-jquery-c-asp-net-mvc/
' http://code.google.com/apis/maps/documentation/geocoding/
' http://code.google.com/apis/maps/documentation/geocoding/index.html
' http://code.google.com/apis/maps/faq.html#geocoder_countries
' http://maps.google.com/maps/api/geocode/json?address=1600+Amphitheatre+Parkway,+Mountain+View,+CA&sensor=false
' http://maps.google.com/maps/api/geocode/json?address=Zurich,+Switzerland&sensor=false
' http://maps.google.com/maps/api/geocode/json?address=SanBernardino,+Switzerland&sensor=false&output=json
' http://maps.google.com/maps/api/geocode/json?address=afsdfKarrrachiii&sensor=false&output=json
' http://math.rice.edu/~pcmi/sphere/sphere.html
' http://math.rice.edu/~pcmi/sphere/
Namespace Google.Maps.JSON
Public Class cAddressComponent
Public long_name
Public short_name
Public types As New List(Of String) '"locality", "country", "postal_code", "sublocality", administrative_area_level_1", administrative_area_level_2", "political"
End Class
Public Class cLocation
Public lat As Double = 0
Public lng As Double = 0
End Class
Public Class cViewPort
Public southwest As New cLocation
Public northeast As New cLocation
End Class
Public Class cBounds
Public southwest As New cLocation
Public northeast As New cLocation
End Class
Public Class cGeometry
Public location As New cLocation
Public location_type As String = "APPROXIMATE" ' "GEOMETRIC_CENTER",
Public viewport As New cViewPort
Public bounds As New cBounds
End Class
Public Class cResult
Public types As New List(Of String) ' "route", "point_of_interest", "establishment", "locality", "sublocality", "political"
Public formatted_address As String
Public address_components As New List(Of cAddressComponent)
Public geometry As New cGeometry
End Class
Public Class cGeoCodeResponse
Public status As String = "ZERO_RESULTS" ' "OK"
Public results As New List(Of cResult)
End Class
End Namespace