translate the IP to a country

using http://dev.maxmind.com/geoip/legacy/geolite/
code from https://github.com/maxmind/geoip-api-csharp2

GeoIP/Location.cs

@@ -0,0 +1,67 @@
+#region Copyright & License Information
+/*
+ * Copyright (C) 2008 MaxMind Inc.  All Rights Reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#endregion
+
+using System;
+using System.IO;
+
+namespace GeoIP
+{
+	public class Location
+	{
+		public String countryCode;
+		public String countryName;
+		public String region;
+		public String city;
+		public String postalCode;
+		public double latitude;
+		public double longitude;
+		public int dma_code;
+		public int area_code;
+		public String regionName;
+		public int metro_code;
+
+		private static double EARTH_DIAMETER = 2 * 6378.2;
+		private static double PI = 3.14159265;
+		private static double RAD_CONVERT = PI / 180;
+
+		public double distance (Location loc)
+		{
+			double delta_lat, delta_lon;
+			double temp;
+
+			double lat1 = latitude;
+			double lon1 = longitude;
+			double lat2 = loc.latitude;
+			double lon2 = loc.longitude;
+
+			// convert degrees to radians
+			lat1 *= RAD_CONVERT;
+			lat2 *= RAD_CONVERT;
+
+			// find the deltas
+			delta_lat = lat2 - lat1;
+			delta_lon = (lon2 - lon1) * RAD_CONVERT;
+
+			// Find the great circle distance
+			temp = Math.Pow(Math.Sin(delta_lat/2), 2) + Math.Cos(lat1) * Math.Cos(lat2) * Math.Pow(Math.Sin(delta_lon/2), 2);
+			return EARTH_DIAMETER * Math.Atan2(Math.Sqrt(temp), Math.Sqrt(1-temp));
+		}
+	}
+}