Android - Much Better Geo Location from just CellID/LAC

Digging a bit deeper!


The previous post that used the ZoneTag and Yahoo GeoCode API’s. Not this one!…Here are 3 screen shots for the following CellID/LAC combinations : (20442/6015, 53361/9800, 32981/6206)

1


2


3


As you may note, This sample has mush finer resolution/location.

Here’s some relevant code snippets:


public void browseTo(int cellid, int lac) throws Exception {
    String url = "http://www.google.com/glm/mmap";
    HttpURL httpURL = new HttpURL(url);
    HostConfiguration host = new HostConfiguration();
    host.setHost(httpURL.getHost(), httpURL.getPort());
    HttpConnection connection = connectionManager.getConnection(host);
    connection.open();

    PostMethod postMethod = new PostMethod(url);
    postMethod.setRequestEntity(new MyRequestEntity(cellid, lac));
    postMethod.execute(new HttpState(), connection);
    InputStream response = postMethod.getResponseBodyAsStream();
    DataInputStream dis = new DataInputStream(response);
    dis.readShort();
    dis.readByte();
    int code = dis.readInt();
    if (code == 0) {
        double lat = (double) dis.readInt() / 1000000D;
        double lng = (double) dis.readInt() / 1000000D;
        dis.readInt();
        dis.readInt();
        dis.readUTF();
        Log.i("LocateMe", "Lat, Long: " + lat + "," + lng);

        /**
         * Start Google Maps and zoom into the lat/long
         */
        ContentURI uri = ContentURI.create("geo:" + lat
                + "," + lng);
        Intent intent = new Intent("android.intent.action.VIEW", uri);
        startActivity(intent);

    } else {
        NotificationManager nm = (NotificationManager)
                getSystemService(NOTIFICATION_SERVICE);
        nm.notifyWithText(100,
                "Could not find lat/long information",
                NotificationManager.LENGTH_SHORT, null);
    }
    connection.close();
}

private static class MyRequestEntity implements RequestEntity {
    int cellId, lac;

    public MyRequestEntity(int cellId, int lac) {
        this.cellId = cellId;
        this.lac = lac;
    }

    public boolean isRepeatable() {
        return true;
    }

    public void writeRequest(OutputStream outputStream) throws
		IOException {
        DataOutputStream os = new DataOutputStream(outputStream);
        os.writeShort(21);
        os.writeLong(0);
        os.writeUTF("fr");
        os.writeUTF("Sony_Ericsson-K750");
        os.writeUTF("1.3.1");
        os.writeUTF("Web");
        os.writeByte(27);

        os.writeInt(0);
        os.writeInt(0);
        os.writeInt(3);
        os.writeUTF("");
        os.writeInt(cellId);  // CELL-ID
        os.writeInt(lac);     // LAC
        os.writeInt(0);
        os.writeInt(0);
        os.writeInt(0);
        os.writeInt(0);
        os.flush();
    }

    public long getContentLength() {
        return -1;
    }

    public String getContentType() {
        return "application/binary";
    }
}

Download the sources and Application - LocateMe-3.0.zip

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Published:
12.1.07 / 12am
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