使用PostGIS进行轨迹分析

从 sqlite 数据库中读取轨迹数据，存储到 postgis 数据库中，再利用 postgis 的特性进行轨迹分析。

track.db

Program.cs

class Program
{
    static void Main(string[] args)
    {
        List<Track> tracks = new List<Track>();

        try
        {
            #region 从Sqlite中读取轨迹数据

            //Sqlite数据库路径
            string sqlitePath = Path.Combine(Environment.CurrentDirectory, "track.db");

            //数据表名称
            string sqliteTb = "T_1140204000334";

            using (SqliteDB sqlite = new SqliteDB(sqlitePath))
            {
                sqlite.Open();
                DataTable dt = sqlite.ExecuteSQL("select * from " + sqliteTb + ";");
                if (dt != null && dt.Rows.Count > 0)
                {
                    for (int i = 0; i < dt.Rows.Count; i++)
                    {
                        tracks.Add(new Track()
                        {
                            B = Convert.ToDouble(dt.Rows[i]["B"]) * 180 / Math.PI,
                            L = Convert.ToDouble(dt.Rows[i]["L"]) * 180 / Math.PI,
                            H = Convert.ToSingle(dt.Rows[i]["H"]),
                            Azi = Convert.ToSingle(dt.Rows[i]["Azi"]),
                            AntH = Convert.ToSingle(dt.Rows[i]["AntH"]),
                            UTCTime = Convert.ToDateTime(dt.Rows[i]["UTCTime"]),
                            Hdop = Convert.ToSingle(dt.Rows[i]["Hdop"]),
                            SolType = Convert.ToInt32(Convert.ToByte(dt.Rows[i]["SolType"]))
                        });
                    }
                }
            }

            Console.WriteLine("Sqlite中的轨迹记录数为：" + tracks.Count);
            Console.WriteLine("---------------------------------------------------------------------");

            #endregion

            #region 向PostgreSQL中存入轨迹数据

            using (PostgresqlDB postgresql = new PostgresqlDB("localhost", "5432", "postgres", "123456", "test"))
            {
                postgresql.Open();

                string tableName = "t_1_1_20150519103523";

                StringBuilder sql = new StringBuilder();

                #region 写入数据

                //删除数据表
                if (postgresql.QueryTableIsExist(tableName))
                {
                    sql.Clear();
                    sql.AppendLine("drop table " + tableName + ";");
                    postgresql.ExecuteNonQuery(sql.ToString());
                }

                postgresql.BeginTransaction();

                try
                {
                    //创建数据表
                    sql.Clear();
                    sql.AppendLine("create table " + tableName + "(");
                    sql.AppendLine("id serial not null,");
                    sql.AppendLine("coord geometry(point, 4326) not null,");
                    sql.AppendLine("h real not null,");
                    sql.AppendLine("azi real not null,");
                    sql.AppendLine("ant_h real not null,");
                    sql.AppendLine("utc_time timestamp with time zone not null,");
                    sql.AppendLine("hdop real not null,");
                    sql.AppendLine("sol_type integer not null,");
                    sql.AppendLine("constraint " + tableName + "_pkey primary key (id)");
                    sql.AppendLine(");");

                    postgresql.ExecuteNonQuery(sql.ToString());

                    //插入记录
                    for (int i = 0; i < tracks.Count; i++)
                    {
                        sql.Clear();
                        sql.AppendLine("insert into " + tableName + "(coord,h,azi,ant_h,utc_time,hdop,sol_type) values(");
                        sql.AppendLine(string.Format("ST_GeomFromText('point({0} {1})',4326),", tracks[i].B, tracks[i].L));
                        sql.AppendLine(tracks[i].H + ",");
                        sql.AppendLine(tracks[i].Azi + ",");
                        sql.AppendLine(tracks[i].AntH + ",");
                        sql.AppendLine("'" + tracks[i].UTCTime.ToString("yyyy-MM-dd HH:mm:ss") + "',");
                        sql.AppendLine(tracks[i].Hdop + ",");
                        sql.AppendLine(tracks[i].SolType.ToString());
                        sql.AppendLine(");");

                        postgresql.ExecuteNonQuery(sql.ToString());
                    }

                    postgresql.Commit();

                    Console.WriteLine("写入postgresql成功！");
                    Console.WriteLine("---------------------------------------------------------------------");
                }
                catch (Exception ex)
                {
                    postgresql.Rollback();
                    Console.WriteLine(ex.Message);
                    Console.WriteLine(ex.StackTrace);
                }

                postgresql.EndTransaction();

                #endregion

                #region 读取数据

                tracks.Clear();

                DataTable dt = postgresql.ExecuteQuery("select st_x(coord) as b, st_y(coord) as l, h, azi, ant_h, utc_time, hdop, sol_type from " + tableName + ";");
                if (dt != null && dt.Rows.Count > 0)
                {                        
                    for (int i = 0; i < dt.Rows.Count; i++)
                    {
                        tracks.Add(new Track() { 
                            B = Convert.ToDouble(dt.Rows[i]["b"]),
                            L = Convert.ToDouble(dt.Rows[i]["l"]),
                            H = Convert.ToSingle(dt.Rows[i]["h"]),
                            Azi = Convert.ToSingle(dt.Rows[i]["azi"]),
                            AntH = Convert.ToSingle(dt.Rows[i]["ant_h"]),
                            UTCTime = Convert.ToDateTime(dt.Rows[i]["utc_time"]),
                            Hdop = Convert.ToSingle(dt.Rows[i]["hdop"]),
                            SolType = Convert.ToInt32(dt.Rows[i]["sol_type"])
                        });
                    }
                }
                Console.WriteLine("读取postgresql中的数据成功！记录数为：" + tracks.Count);
                Console.WriteLine("---------------------------------------------------------------------");

                #endregion

                #region 轨迹分析

                //轨迹总长度
                double dist = 0;
                DataTable dtDistance = postgresql.ExecuteQuery("select st_length(st_makeline(st_transform(coord, 4504))) from " + tableName + ";");
                if (dtDistance != null && dtDistance.Rows.Count > 0)
                {
                    dist = Convert.ToDouble(dtDistance.Rows[0][0]);
                    Console.WriteLine("轨迹总长度：" + dist + " 米");
                    Console.WriteLine("---------------------------------------------------------------------");
                }

                //轨迹总时间
                double seconds = 0;
                DataTable dtDateTime = postgresql.ExecuteQuery("select max(utc_time), min(utc_time) from " + tableName + ";");
                if (dtDateTime != null && dtDateTime.Rows.Count > 0)
                {
                    DateTime max = Convert.ToDateTime(dtDateTime.Rows[0][0]);
                    DateTime min = Convert.ToDateTime(dtDateTime.Rows[0][1]);
                    seconds = (max - min).TotalSeconds;
                    Console.WriteLine("轨迹总时间：" + seconds + " 秒");
                    Console.WriteLine("---------------------------------------------------------------------");
                }

                //轨迹平均速度
                if (seconds != 0)
                {
                    Console.WriteLine("轨迹平均速度：" + dist / seconds + " 米/秒");
                    Console.WriteLine("---------------------------------------------------------------------");
                }

                //轨迹瞬时速度（计算相邻两条记录的距离及时间间隔）
                //extract(epoch from time1-time2):计算时间间隔的总秒数
                DataTable dtDelta = postgresql.ExecuteQuery("select st_distance(st_transform(p1.coord,4504),st_transform(p2.coord,4504)) as delta_d, extract(epoch from p1.utc_time-p2.utc_time) as delta_t from " + tableName + " as p1, " + tableName + " as p2 where p1.id = p2.id+1;");
                if (dtDelta != null && dtDelta.Rows.Count > 0)
                {
                    double delta_d = Convert.ToDouble(dtDelta.Rows[dtDelta.Rows.Count - 1]["delta_d"]);
                    double delta_t = Convert.ToDouble(dtDelta.Rows[dtDelta.Rows.Count - 1]["delta_t"]);
                    if (delta_t != 0)
                    {
                        Console.WriteLine("最后一个点的分析结果为：\r\n    瞬时位移：" + delta_d + " 米" +
                            "\r\n    时间间隔：" + delta_t + " 秒" +
                            "\r\n    瞬时速度：" + delta_d / delta_t + " 米/秒");
                        Console.WriteLine("---------------------------------------------------------------------");
                    }
                }

                #endregion
            }

            #endregion
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            Console.WriteLine(ex.StackTrace);
        }
        Console.Read();
    }
}

运行结果为：

Sqlite中的轨迹记录数为：1521
---------------------------------------------------------------------
写入postgresql成功！
---------------------------------------------------------------------
读取postgresql中的数据成功！记录数为：1521
---------------------------------------------------------------------
轨迹总长度：16775.455657666 米
---------------------------------------------------------------------
轨迹总时间：353325 秒
---------------------------------------------------------------------
轨迹平均速度：0.0474788244751037 米/秒
---------------------------------------------------------------------
最后一个点的分析结果为：
    瞬时位移：5.32844146492802 米
    时间间隔：1 秒
    瞬时速度：5.32844146492802 米/秒
---------------------------------------------------------------------

Track.cs

public class Track
{
    public double B;
    public double L;
    public float H;
    public float Azi;
    public float AntH;
    public DateTime UTCTime;
    public float Hdop;
    public int SolType;
}

SqliteDB.cs

/// <summary>
/// Sqlite数据库操作类
/// </summary>
public class SqliteDB : IDisposable
{
    #region 字段

    /// <summary>
    /// 数据库连接字符串构造器
    /// </summary>
    private SQLiteConnectionStringBuilder _connStr = null;

    /// <summary>
    /// 数据库连接器
    /// </summary>
    private SQLiteConnection _conn = null;

    /// <summary>
    /// 通过连接器创建NpgsqlCommand对象，用于执行SQL语句
    /// </summary>
    private SQLiteCommand _comm = null;

    /// <summary>
    /// 事务管理对象
    /// </summary>
    private SQLiteTransaction _trans = null;

    #endregion

    #region 构造函数

    public SqliteDB(string filePath)
    {
        _connStr = new SQLiteConnectionStringBuilder();
        _connStr.DataSource = filePath;
        _conn = new SQLiteConnection(_connStr.ToString());
        _comm = _conn.CreateCommand();
    }

    ~SqliteDB()
    {
    }

    #endregion

    #region 静态方法

    /// <summary>
    /// 创建数据库
    /// </summary>
    /// <param name="filePath">db文件路径+文件名</param>
    public static void CreateDB(string filePath)
    {
        try
        {
            SQLiteConnection.CreateFile(filePath);
        }
        catch
        {
            throw;
        }
    }

    #endregion

    #region 公共方法

    #region 数据库操作：连接数据库、断开数据库、加密数据库

    /// <summary>
    /// 打开数据库连接
    /// </summary>
    /// <returns>是否连接成功</returns>
    public bool Open()
    {
        try
        {
            _conn.Open();
            return true;
        }
        catch
        {
            Close();
            return false;
            throw;
        }
    }

    /// <summary>
    /// 打开数据库连接
    /// </summary>
    /// <param name="password">密码</param>
    /// <returns>是否连接成功</returns>
    public bool Open(string password)
    {
        try
        {
            _conn.SetPassword(password);
            _conn.Open();
            return true;
        }
        catch
        {
            Close();
            return false;
            throw;
        }
    }

    /// <summary>
    /// 关闭数据库连接
    /// </summary>
    public void Close()
    {
        if (_conn != null)
        {
            _comm.Dispose();
            _conn.Close();
            _conn.Dispose();
        }
    }

    /// <summary>
    /// 给sqlite数据库加密
    /// </summary>
    /// <param name="password">密码</param>
    public void Encrypt(string password)
    {
        try
        {
            if (_conn != null)
            {
                _conn.ChangePassword(password);
            }
        }
        catch
        {
            throw;
        }
    }

    #endregion

    #region 查询

    /// <summary>
    /// 执行sql语句
    /// </summary>
    /// <param name="sql"></param>
    /// <returns></returns>
    public DataTable ExecuteSQL(string sql)
    {
        try
        {
            _comm.Transaction = _trans;
            _comm.CommandText = sql;
            DataTable dt = new DataTable();
            using (SQLiteDataAdapter adapter = new SQLiteDataAdapter(_comm))
            {
                adapter.Fill(dt);
            }
            return dt;
        }
        catch
        {
            throw;
        }
    }

    #endregion

    #region 事务管理

    /// <summary>
    /// 开始执行事务
    /// </summary>
    public void BeginTransaction()
    {
        if (_conn != null)
        {
            _trans = _conn.BeginTransaction();
        }
    }

    /// <summary>
    /// 事务结束，保存并提交数据库数据，
    /// </summary>
    public void Commit()
    {
        if (_trans != null)
        {
            _trans.Commit();
        }
    }

    /// <summary>
    /// 回滚事务
    /// </summary>
    public void Rollback()
    {
        if (_trans != null)
        {
            _trans.Rollback();
        }
    }

    /// <summary>
    /// 结束事务，并释放资源
    /// </summary>
    public void EndTransaction()
    {
        if (_trans != null)
        {
            _trans.Dispose();
            _trans = null;
        }
    }

    #endregion

    #endregion

    #region IDisposable 成员

    public void Dispose()
    {
        this.Close();
    }

    #endregion
}

PostgresqlDB.cs

/// <summary>
/// 数据库管理类
/// 直接操作数据库
/// </summary>
public class PostgresqlDB : IDisposable
{
    #region 字段

    #region 连接配置

    /// <summary>
    /// 服务器地址
    /// </summary>
    private string server;

    /// <summary>
    /// 端口
    /// </summary>
    private string port;

    /// <summary>
    /// 用户名
    /// </summary>
    private string username;

    /// <summary>
    /// 密码
    /// </summary>
    private string password;

    /// <summary>
    /// 数据库名称
    /// </summary>
    private string db;

    #endregion

    #region 数据库操作相关变量

    /// <summary>
    /// 数据库连接器
    /// </summary>
    private NpgsqlConnection _conn;

    /// <summary>
    /// 通过连接器创建NpgsqlCommand对象，用于执行SQL语句
    /// </summary>
    private NpgsqlCommand _comm;

    /// <summary>
    /// 将数据表中获取的记录生成DataSet
    /// </summary>
    private NpgsqlDataAdapter _adapter;

    /// <summary>
    /// 创建一个事务对象
    /// </summary>
    private NpgsqlTransaction _trans;

    #endregion

    #endregion

    #region 构造函数

    private PostgresqlDB() { }

    /// <summary>
    /// 数据库管理类
    /// </summary>
    /// <param name="dbConfig">数据库配置</param>
    public PostgresqlDB(string server, string port, string username, string password, string db)
    {
        this.server = server;
        this.port = port;
        this.username = username;
        this.password = password;
        this.db = db;
    }

    ~PostgresqlDB()
    {
    }

    #endregion

    #region 公共方法

    #region 数据库操作：连接数据库、断开数据库、数据库连接状态

    /// <summary>
    /// 打开数据库连接
    /// </summary>
    /// <returns></returns>
    public bool Open()
    {
        try
        {
            //构造SQL语句
            string sql = String.Format(
                "server={0};port={1};userid={2};password={3};database={4};pooling=true;maxpoolsize=40;timeout=5;",
                server, port, username, password, db);

            //初始化数据库连接参数
            _conn = new NpgsqlConnection(sql);
            //打开数据库连接
            _conn.Open();
            //初始化
            _comm = _conn.CreateCommand();
            _adapter = new NpgsqlDataAdapter(_comm);
            _trans = null;
            return true;
        }
        catch (Exception ex)
        {
            if (_conn != null)
                _conn.Close();
            _conn = null;
            return false;
        }
    }

    /// <summary>
    /// 关闭数据库连接
    /// </summary>
    public void Close()
    {
        if (_conn != null)
        {
            _adapter.Dispose();
            _adapter = null;
            _comm.Dispose();
            _comm = null;
            _conn.Close();
            _conn.Dispose();
            _conn = null;
        }
    }

    /// <summary>
    /// 获取数据库的连接状态
    /// </summary>
    /// <returns>true表示已连接，false表示未连接</returns>
    public bool GetConnStatus()
    {
        return (_conn != null && _conn.State == ConnectionState.Open);
    }

    #endregion

    #region 数据表操作：查询数据表或视图是否存在

    /// <summary>
    /// 查询指定名称的数据表是否存在
    /// </summary>
    /// <param name="tableName">数据表名</param>
    /// <returns>true:存在，false:不存在</returns>
    public bool QueryTableIsExist(string tableName)
    {
        //构建SQL语句
        string sql = String.Format("select count(*) from pg_tables where tablename = '{0}';", tableName.ToLower());

        //执行SQL语句
        _comm.Transaction = _trans;
        _comm.CommandText = sql;
        NpgsqlDataReader readerTemp = _comm.ExecuteReader();

        //获取查询结果
        long value = -1;
        if (readerTemp.HasRows == true)
        {
            readerTemp.Read();
            value = readerTemp.GetInt64(0);
        }

        //释放资源
        readerTemp.Close();

        //value=1表示数据表存在；value=0表示数据表不存在
        if (value > 0)
        {
            return true;
        }
        return false;
    }

    /// <summary>
    /// 查询指定名称的视图是否存在
    /// </summary>
    /// <param name="viewName">视图名</param>
    /// <returns>true:存在，false:不存在</returns>
    public bool QueryViewIsExist(string viewName)
    {
        //构建SQL语句
        string sql = String.Format("select count(*) from pg_views where viewname = '{0}';", viewName.ToLower());

        //执行SQL语句
        _comm.Transaction = _trans;
        _comm.CommandText = sql;
        NpgsqlDataReader readerTemp = _comm.ExecuteReader();

        //获取查询结果
        long value = -1;
        if (readerTemp.HasRows == true)
        {
            readerTemp.Read();
            value = readerTemp.GetInt64(0);
        }

        //释放资源
        readerTemp.Close();

        //value=1表示数据表存在；value=0表示数据表不存在
        if (value == 0)
        {
            return false;
        }
        return true;
    }

    #endregion

    #region 执行sql语句

    /// <summary>
    /// 执行sql语句
    /// </summary>
    /// <param name="sql"></param>
    public void ExecuteNonQuery(string sql)
    {
        try
        {
            _comm.Transaction = _trans;
            _comm.CommandText = sql;
            _comm.ExecuteNonQuery();
        }
        catch
        {
            throw;
        }
    }

    /// <summary>
    /// 执行sql语句
    /// </summary>
    /// <param name="sql"></param>
    /// <returns></returns>
    public DataTable ExecuteQuery(string sql)
    {
        try
        {                
            _comm.Transaction = _trans;
            _comm.CommandText = sql;
            DataTable dt = new DataTable();
            using (NpgsqlDataAdapter adapter = new NpgsqlDataAdapter(_comm))
            {
                adapter.Fill(dt);
            }
            return dt;
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

    #endregion

    #region 事务管理

    /// <summary>
    /// 开始执行事务
    /// </summary>
    public void BeginTransaction()
    {
        if (_conn != null)
        {
            _trans = _conn.BeginTransaction();
        }
    }

    /// <summary>
    /// 事务结束，保存并提交数据库数据，
    /// </summary>
    public void Commit()
    {
        if (_trans != null)
        {
            _trans.Commit();
        }
    }

    /// <summary>
    /// 回滚事务
    /// </summary>
    public void Rollback()
    {
        if (_trans != null)
        {
            _trans.Rollback();
        }
    }

    /// <summary>
    /// 结束事务，并释放资源
    /// </summary>
    public void EndTransaction()
    {
        if (_trans != null)
        {
            _trans.Dispose();
            _trans = null;
        }
    }

    #endregion

    #endregion

    public void Dispose()
    {
        this.Close();
    }
}