[！[Header] [1]] [1]我正在做一个小项目来获取经度和经度
请告诉我如何从数据中提取真实的纬度和经度值。
using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.IO;
using System.Linq;
namespace SimpleUdpReciever
{
class pProgram
{
static void Main(string[] args)
{
int localPort = 18006;
IPEndPoint remoteSender = new IPEndPoint(IPAddress.Any, 0);
bool flag = false;
for (int i = 0; i < args.Length; i++)
{
string cmd = args[i];
string value;
int tempInt;
IPAddress tempAddress;
switch (cmd)
{
case "-lp":
value = GetValue(args, ref i);
if (int.TryParse(value, out tempInt))
localPort = tempInt;
break;
case "-rp":
value = GetValue(args, ref i);
if (int.TryParse(value, out tempInt))
remoteSender.Port = tempInt;
break;
case "-rh":
value = GetValue(args, ref i);
if (IPAddress.TryParse(value, out tempAddress))
remoteSender.Address = tempAddress;
else if (int.TryParse(value, out tempInt) && tempInt == 0)
remoteSender.Address = IPAddress.Any;
break;
case "-?":
default:
PrintHelpText();
flag = true;
break;
}
}
// Exit application after help text is displayed
if (flag)
return;
// Create UDP client
UdpClient client = new UdpClient(localPort);
UdpState state = new UdpState(client, remoteSender);
// Start async receiving
client.BeginReceive(new AsyncCallback(DataReceived), state);
// Wait for any key to terminate application
Console.ReadKey();
client.Close();
}
public static string ByteArrayToString(byte[] ba)
{
StringBuilder hex = new StringBuilder(ba.Length * 2);
foreach (byte b in ba)
hex.AppendFormat("{0:x2}", b);
return hex.ToString();
}
private static void DataReceived(IAsyncResult ar)
{
UdpClient c = (UdpClient)((UdpState)ar.AsyncState).c;
IPEndPoint wantedIpEndPoint = (IPEndPoint)((UdpState)(ar.AsyncState)).e;
IPEndPoint receivedIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
Byte[] receiveBytes = c.EndReceive(ar, ref receivedIpEndPoint);
bool isRightHost = (wantedIpEndPoint.Address.Equals(receivedIpEndPoint.Address)) || wantedIpEndPoint.Address.Equals(IPAddress.Any);
bool isRightPort = (wantedIpEndPoint.Port == receivedIpEndPoint.Port) || wantedIpEndPoint.Port == 0;
if (isRightHost && isRightPort)
{
// Console.WriteLine(ByteArrayToString(receiveBytes));
if (receiveBytes[3] == 187 && receiveBytes[4] == 1)
{
//Printing output
Console.WriteLine("4 bytes starting with 5 yields: {0} {1} {2} {3} {4}",
receiveBytes[5],
receiveBytes[6],
receiveBytes[7],
receiveBytes[8],
BitConverter.ToInt32(receiveBytes, 4));
Console.WriteLine("4 bytes starting with 9 yields: {0} {1} {2} {3} {4}",
receiveBytes[9],
receiveBytes[10],
receiveBytes[11],
receiveBytes[11],
BitConverter.ToInt32(receiveBytes, 9));
}
}
// Restart listening for udp data packages
c.BeginReceive(new AsyncCallback(DataReceived), ar.AsyncState);
}
private static string GetValue(string[] args, ref int i)
{
string value = String.Empty;
if (args.Length >= i + 2)
{
i++;
value = args[i];
}
return value;
}
private static void PrintHelpText()
{
Console.WriteLine("Simple Udp Receiver is an application that prints incoming data to screen.");
Console.WriteLine("Data is converted to ASCII before printing.");
Console.WriteLine("*** Amund Gjersoe 2010 ***\n");
Console.WriteLine("Command switches:");
Console.WriteLine("-? : Displays this text.");
Console.WriteLine("-lp : Set local receiving port. \"-lp 4001\" Default: 11000");
Console.WriteLine("-rp : Set remote sender port. \"-rp 4001\" Default: 0 (Any port)");
Console.WriteLine("-rh : Set remote sender ip. \"-rh 192.168.1.10\" Default: 0 (Any ip)");
Console.WriteLine("\n Example of usage:\nSimpleUdpReciver.exe -lp 11000 -rh 192.168.10.10 -rp 4001");
}
}
}
包结构[！[包] [4]] [4]
[！[1d 187包的全部数据] [5]] [5]
答案 0 :(得分：1)
GPS消息使用Big Endian整数。以下代码仅关注有效内容以及如何使用GPSMessage和System.IO.MemoryStream（读取小端格式）将其转换为System.IO.BinaryReader结构。为了纠正错误的字节顺序，示例代码使用System.Net.IPAddress.NetworkToHostOrder()。
using System;
namespace ConsoleWindowPos
{
struct GPSMessage
{
public byte ValidityFlags { get; set; }
public Int32 TargetLatRaw { get; set; }
public float TargetLat { get { return 90.0f / (Int32.MaxValue-1) * (float)TargetLatRaw ; } }
public Int32 TargetLongRaw { get; set; }
public float TargetLong { get { return 180.0f / (Int32.MaxValue-1) * (float)TargetLongRaw; } }
public static GPSMessage FromBinary(byte[] payload)
{
System.IO.MemoryStream stream = new System.IO.MemoryStream(payload);
System.IO.BinaryReader reader = new System.IO.BinaryReader(stream);
GPSMessage result = new GPSMessage();
result.ValidityFlags = reader.ReadByte();
result.TargetLatRaw = System.Net.IPAddress.NetworkToHostOrder(reader.ReadInt32());
result.TargetLongRaw = System.Net.IPAddress.NetworkToHostOrder(reader.ReadInt32());
return result;
}
public override string ToString()
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
sb.AppendLine("GPSMessage: {");
sb.AppendFormat(" ValidityFlags = 0x{0:X2};", ValidityFlags);
sb.AppendLine();
sb.Append(" TargetLatRaw = ");
sb.Append(TargetLatRaw);
sb.AppendLine(";");
sb.Append(" TargetLat = ");
sb.Append(TargetLat);
sb.AppendLine(";");
sb.Append(" TargetLongRaw = ");
sb.Append(TargetLongRaw);
sb.AppendLine(";");
sb.Append(" TargetLong = ");
sb.Append(TargetLong);
sb.AppendLine(";");
sb.Append("}");
return sb.ToString();
}
}
class Program
{
static void Main(string[] args)
{
byte[] payload = { 1,204,99,37,86,103,105,241,16,0,107,0,16,242,151,0,0,190 };
var message = GPSMessage.FromBinary(payload);
System.Console.WriteLine(message.ToString());
System.Console.ReadLine();
}
}
}
此代码的输出为：
GPSMessage: {
ValidityFlags = 0x01;
TargetLatRaw = -865917610;
TargetLat = -36.29019;
TargetLongRaw = 1734996240;
TargetLong = 145.4257;
}
这似乎是问题的作者所期待的。