diff --git a/Program.cs b/Program.cs
index ddf86c7..2b6e3af 100644
--- a/Program.cs
+++ b/Program.cs
@@ -1,15 +1,184 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
+using System.IO;
 using System.Text;
 using System.Threading.Tasks;
+using System.Json;
+using MKCoolsoft.GPXLib;
+
 
 namespace starlineonline2gpx
 {
+    class Date
+    {
+        private static DateTime UnixEpoch =
+        new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+        public static TimeZoneInfo TimeZone = TimeZoneInfo.Local;
+
+        public static long minSeconds = long.MaxValue;
+        public static long maxSeconds = long.MinValue;
+
+        public static DateTime DateTimeFromUnixTimestampSeconds(long seconds)
+        {
+            if (seconds < minSeconds) minSeconds = seconds;
+            if (seconds > maxSeconds) maxSeconds = seconds;
+            return UnixEpoch.AddSeconds(seconds);
+        }
+    }
+
     class Program
     {
+        static decimal Minlat = decimal.MaxValue;
+        static decimal Maxlat = decimal.MinValue;
+        static decimal Minlon = decimal.MaxValue;
+        static decimal Maxlon = decimal.MinValue;
+
         static void Main(string[] args)
         {
+            if (args.Length > 0 && File.Exists(args[0]))
+            {
+                var path = args[0];
+                using (StreamReader sr = new StreamReader(path))
+                {
+                    var json = JsonValue.Parse(sr.ReadToEnd());
+
+                    GPXLib gpx = new GPXLib();
+
+                    var meta = json["meta"];
+                    var data = json["data"];
+                    var trackNum = 0;
+                    var waypointNum = 0;
+                    foreach(JsonValue elem in data)
+                    {
+                        string type = elem["type"];
+                        switch(type)
+                        {
+                            case "TZ":
+                                ParseTimezone(gpx, elem);
+                                break;
+                            case "TRACK":
+                                ParseTrack(gpx, elem, ++trackNum);
+                                break;
+                            case "NO_SIGNAL":
+                                ParseNoSignal(gpx, elem);
+                                break;
+                            case "WAYPOINT":
+                                ParseWaypoint(gpx, elem, ++waypointNum);
+                                break;
+                            case "STOP":
+                                ParseStop(gpx, elem);
+                                break;
+                            default:
+                                throw new NotImplementedException();
+
+                        }
+                    }
+
+
+                    gpx.Metadata.Name = "Starline GPX Track";
+
+                    var startDate = Date.DateTimeFromUnixTimestampSeconds(Date.minSeconds);
+                    var endDate = Date.DateTimeFromUnixTimestampSeconds(Date.maxSeconds);
+                    gpx.Metadata.Desc = String.Format("Track from {0} to {1}", startDate, endDate);
+
+                    gpx.Creator = "starlineonline2gpx converter";
+
+                    gpx.Metadata.Bounds.Maxlat = Maxlat;
+                    gpx.Metadata.Bounds.Minlat = Minlat;
+                    gpx.Metadata.Bounds.Maxlon = Maxlon;
+                    gpx.Metadata.Bounds.Minlon = Minlon;
+                    gpx.Metadata.Time = startDate;
+                    gpx.Metadata.TimeSpecified = true;
+
+                    var author = new Person();
+                    author.Link.Href = @"https://github.com/DJm00n/starlineonline2gpx";
+                    author.Email.Id = @"dimitriy.ryazantcev";
+                    author.Email.Domain = "gmail.com";
+                    author.Name = @"Dimitriy Ryazantcev";
+
+                    gpx.Metadata.Author = author;
+
+
+                    gpx.SaveToFile(Path.ChangeExtension(path, "gpx"));
+                }
+            }
+        }
+
+        private static void TrackMinMax(decimal lat, decimal lon)
+        {
+            if (lat < Minlat) Minlat = lat;
+            if (lat > Maxlat) Maxlat = lat;
+
+            if (lon < Minlon) Minlon = lon;
+            if (lon > Maxlon) Maxlon = lon;
+        }
+
+        private static void ParseNoSignal(GPXLib gpx, JsonValue elem)
+        {
+            //throw new NotImplementedException();
+        }
+
+        private static void ParseStop(GPXLib gpx, JsonValue elem)
+        {
+            //throw new NotImplementedException();
+        }
+
+        private static void ParseWaypoint(GPXLib gpx, JsonValue elem, int waypointNum)
+        {
+            Wpt waypoint = new Wpt
+            {
+                Name = String.Format("Waypoint {0}", waypointNum),
+                Lat = elem["x"],
+                Lon = elem["y"],
+                Ele = elem["z"],
+                EleSpecified = elem.ContainsKey("z") && elem["z"] != 0,
+                Sat = Convert.ToString((int)elem["sat_qty"]),
+                Time = Date.DateTimeFromUnixTimestampSeconds(elem["t"]),
+                TimeSpecified = elem.ContainsKey("t")
+            };
+
+            gpx.WptList.Add(waypoint);
+            TrackMinMax(waypoint.Lat, waypoint.Lon);
+        }
+
+        private static void ParseTimezone(GPXLib gpx, JsonValue elem)
+        {
+            string displayName = "Local Time Zone";
+            string standardName = "Local Time";
+            TimeSpan offset = TimeSpan.FromSeconds(elem["time_shift"]);
+            TimeZoneInfo local = TimeZoneInfo.CreateCustomTimeZone(standardName, offset, displayName, standardName);
+            Date.TimeZone = local;
+            //TODO save this timezone somewhere in gpx file
+        }
+
+        private static void ParseTrack(GPXLib gpx, JsonValue elem, int trackNum)
+        {
+            Trkseg segment = new Trkseg();
+
+            foreach (JsonValue node in elem["nodes"])
+            {
+                Wpt wpt = new Wpt
+                {
+                    Lat = node["x"],
+                    Lon = node["y"],
+                    Ele = node["z"],
+                    EleSpecified = node.ContainsKey("z") && node["z"] != 0,
+                    Sat = Convert.ToString((int)node["sat_qty"]),
+                    Time = Date.DateTimeFromUnixTimestampSeconds(node["t"]),
+                    TimeSpecified = node.ContainsKey("t")
+                };
+
+                segment.TrkptList.Add(wpt);
+                TrackMinMax(wpt.Lat, wpt.Lon);
+            }
+
+            Trk track = new Trk(String.Format("Track {0}", trackNum))
+            {
+                Number = trackNum.ToString()
+            };
+            track.TrksegList.Add(segment);
+
+            gpx.TrkList.Add(track);
         }
     }
 }
diff --git a/packages.config b/packages.config
new file mode 100644
index 0000000..ee3219c
--- /dev/null
+++ b/packages.config
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="MKCoolsoft.GPXLib" version="1.0.2" targetFramework="net452" />
+  <package id="System.Json" version="4.4.0" targetFramework="net452" />
+</packages>
\ No newline at end of file
diff --git a/starlineonline2gpx.csproj b/starlineonline2gpx.csproj
index 94e8a9b..d568a6f 100644
--- a/starlineonline2gpx.csproj
+++ b/starlineonline2gpx.csproj
@@ -33,8 +33,16 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="MKCoolsoft.GPXLib, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL">
+      <HintPath>packages\MKCoolsoft.GPXLib.1.0.2\lib\MKCoolsoft.GPXLib.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="System" />
     <Reference Include="System.Core" />
+    <Reference Include="System.Json, Version=2.0.5.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
+      <HintPath>packages\System.Json.4.4.0\lib\netstandard1.0\System.Json.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />
@@ -48,6 +56,7 @@
   </ItemGroup>
   <ItemGroup>
     <None Include="App.config" />
+    <None Include="packages.config" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it.