Code to Get GPS Coordinates from Address (VB6/VBA/

问题:

I believe the Google API allows you to get coordinates for a given address. However, most (or should I say all) of the examples I've found aren't for vb. Usually it's some javascript example that just leaves me confused.

Here's some code I have that uses a geocoding service. This works great. It's just that I want to query Google Maps directly myself.

Public Function fgGetLatAndLongUsingAddress(sAddress As String) As String

    'This function works best with a complete address including the zip code
    Dim sResponseText As String, sReturn As String

    sReturn = "none"

    Dim objHttp As Object, sQuery As String
    sQuery = "http://rpc.geocoder.us/service/csv?address=" & Replace(sAddress, " ", "+")
    Set objHttp = CreateObject("Msxml2.ServerXMLHTTP")
    objHttp.Open "GET", sQuery, False
    objHttp.send
    sResponseText = objHttp.ResponseText
    gsLastLatLongResponseText = sResponseText
    Set objHttp = Nothing


    If Len(sResponseText) > 0 Then
        If InStr(sResponseText, "Bad Request") > 0 Then
            'Do Nothing
        ElseIf InStr(sResponseText, "couldn't find this address") > 0 Then
            'Do Nothing
        Else
            If InStr(sResponseText, vbCrLf) > 0 Then
                'We got more than one result
            End If
            If InStr(sResponseText, ",") > 0 Then
                Dim aryInfo() As String
                aryInfo = Split(sResponseText, ",")
                sReturn = aryInfo(0) & "," & aryInfo(1)
            End If
        End If
    End If


    fgGetLatAndLongUsingAddress = sReturn

End Function

回答1:

This should do the job. You need to add a reference to the MSXML6 library (Microsoft XML, v6.0) via Tools > References in Excel

Option Explicit

Function getGoogleMapsGeocode(sAddr As String) As String

Dim xhrRequest As XMLHTTP60
Dim sQuery As String
Dim domResponse As DOMDocument60
Dim ixnStatus As IXMLDOMNode
Dim ixnLat As IXMLDOMNode
Dim ixnLng As IXMLDOMNode


' Use the empty string to indicate failure
getGoogleMapsGeocode = ""

Set xhrRequest = New XMLHTTP60
sQuery = "http://maps.googleapis.com/maps/api/geocode/xml?sensor=false&address="
sQuery = sQuery & Replace(sAddr, " ", "+")
xhrRequest.Open "GET", sQuery, False
xhrRequest.send

Set domResponse = New DOMDocument60
domResponse.loadXML xhrRequest.responseText
Set ixnStatus = domResponse.selectSingleNode("//status")

If (ixnStatus.Text <> "OK") Then
    Exit Function
End If

Set ixnLat = domResponse.selectSingleNode("/GeocodeResponse/result/geometry/location/lat")
Set ixnLng = domResponse.selectSingleNode("/GeocodeResponse/result/geometry/location/lng")

getGoogleMapsGeocode = ixnLat.Text & ", " & ixnLng.Text

End Function

The only real differences to your example are:

• changing the URL and parameters of the query to use the Google API
• treating the response as an XML document and using XPath to extract the required results

Obviously there's no error handling whatsoever in my code but it should give you an idea of what you need to use the API. You definitely want to consult the API documentation yourself to find out about rate limiting etc

回答2:

Thanks for that code! It works great. Thanks for the heads up on the rate limits. Here's what Google has to say:

Use of the Google Geocoding API is subject to a query limit of 2,500 geolocation requests per day. (User of Google Maps API Premier may perform up to 100,000 requests per day.) This limit is enforced to prevent abuse and/or repurposing of the Geocoding API, and this limit may be changed in the future without notice. Additionally, we enforce a request rate limit to prevent abuse of the service. If you exceed the 24-hour limit or otherwise abuse the service, the Geocoding API may stop working for you temporarily. If you continue to exceed this limit, your access to the Geocoding API may be blocked. Note: the Geocoding API may only be used in conjunction with a Google map; geocoding results without displaying them on a map is prohibited. For complete details on allowed usage, consult the Maps API Terms of Service License Restrictions.