topic Re: GPS Logging in .NET Maps SDK Questions

GPS Logging

pshearon — Tue, 26 Jul 2022 15:52:45 GMT

How can I log NMEA messages coming from a NmeaLocationDataSource?

public event EventHandler<Location>? LocationChanged; <--- this gives a location object, but not the raw messages that lead to that point. What are the chances of getting those in an event? Or some other way?

Regards,

Patrick Shearon

Re: GPS Logging

dotMorten_esri — Tue, 26 Jul 2022 19:03:42 GMT

There's no out-of-the-box support for this today (it's on our backlog). However, you could intercept the NMEA stream with a stream interceptor class. For example:

public class StreamInterceptor : Stream { private readonly Stream _baseStream; public StreamInterceptor(Stream baseStream) { _baseStream = baseStream; } public event EventHandler<string>? OnData; public override int Read(byte[] buffer, int offset, int count) { int read = _baseStream.Read(buffer, offset, count); if (read > 0) { OnData?.Invoke(this, Encoding.UTF8.GetString(buffer, 0, read)); } return read; } public override bool CanRead => _baseStream.CanRead; public override bool CanSeek => _baseStream.CanSeek; public override bool CanWrite => _baseStream.CanWrite; public override long Length => _baseStream.Length; public override long Position { get => _baseStream.Position; set => _baseStream.Position = value; } public override void Flush() => _baseStream.Flush(); public override long Seek(long offset, SeekOrigin origin) => _baseStream.Seek(offset, origin); public override void SetLength(long value) => _baseStream.SetLength(value); public override void Write(byte[] buffer, int offset, int count) => _baseStream.Write(buffer, offset, count); }

Then you could create the nmea datasource using this new stream type and listen to the OnData event:

SerialPort p = new SerialPort("COM3"); NmeaLocationDataSource ds = NmeaLocationDataSource.FromStreamCreator( onStart: (ds) => { p.Open(); var sl = new StreamInterceptor(p.BaseStream); sl.OnData += (s, nmeaString) => { Console.Write(nmeaString); // NMEA raw data string }; return Task.FromResult<System.IO.Stream>(sl); }, onStop: (ds) => { p.Close(); return Task.CompletedTask; } ); ds.StartAsync();

Re: GPS Logging

pshearon — Wed, 27 Jul 2022 22:08:48 GMT

What would you recommend for FromBluetooth devices?

Re: GPS Logging

dotMorten_esri — Wed, 27 Jul 2022 22:15:49 GMT

If you're using .NET 6, you don't actually need to use the bluetooth version, but can still use them as a serial port (Windows will assign them port numbers). But otherwise, you'd have to grab the bluetooth data stream yourself before using the above.

Re: GPS Logging

pshearon — Thu, 28 Jul 2022 01:30:39 GMT

Thanks a lot, your insight has been very helpful. Since it's all on windows (.NET 6) I will be going with System.IO.Ports.SerialPort and that StreamInterceptor. All of my tests worked with your suggestions!

Regards,

Patrick Shearon

Re: GPS Logging

FelicityRhone — Wed, 11 Mar 2026 18:59:12 GMT

I know this is a very old thread, but I was just looking for this and found that there is an event now as of the Maps SDK 200.7. So, for anyone else landing here in the future:

https://developers.arcgis.com/net/api-reference/api/netwin/Esri.ArcGISRuntime/Esri.ArcGISRuntime.Location.NmeaLocationDataSource.SentenceReceived.html