Signal K•4mo ago

Possible to create AtoNs with SignalK API?

I am looking for a way to create AtoNs with a Python app using SignalK to forward to NMEA 2000 PGN 129041 and NMEA 0183 !AIVDM.
Is it possible to PUT or POST an ATON?

24 Replies

Scott Bender•4mo ago

You need to use WebSockets and send deltas. https://signalk.org/specification/1.7.0/doc/

Signal K Specification

Scott Bender•4mo ago

Depending on where you are getting the data. Might be easier to do with node-red.

AlienTechnologyOP•4mo ago

node-red instead of Python or instead of WebSockets?

Scott Bender•4mo ago

Both

AlienTechnologyOP•4mo ago

We have an existing app in Python, so it will have to start there I think. I still seem to be missing something. Sending auth request works, but no response to sending AtoN. What am I doing wrong?

Scott Bender•4mo ago

There won’t be any response.

AlienTechnologyOP•4mo ago

import asyncio
from websockets import connect

async def hello(uri):
    async with connect(uri) as websocket:
        message = await websocket.recv()
        print(message)

        login_msg ='{"requestId": "1234-45653-343454","login": {"username": "sample","password": "fakepassword"}}'
        print(f'\n send >> {login_msg}')
        await websocket.send(login_msg)
        message = await websocket.recv()
        print(f'\n recv << {message}')

        # update
        sampleAton = '{"context": "atons.urn:mrn:imo:mmsi:123456789","updates": [{"values": [{"path": "navigation.position.longitude","value": -117.23770},{"path": "navigation.position.latitude","value": 32.78577},{"path": "name","value": "XXX--XXX"},{"path": "virtual","value": "true"},{"path": "atonType.name","value": "Special Mark"}]}]}'
        # full
        # sampleAton = "{'source': {'label': 'can0', 'type': 'NMEA2000', 'pgn': 129041, 'src': '1', 'canName': 'c03282004a6ea6f0', 'deviceInstance': 0}, 'timestamp': '2024-08-25T22:40:14.568Z', 'values': [{'path': '', 'value': {'name': 'PYTHON-111-004'}}, {'path': 'navigation.position', 'value': {'longitude': -117.23770, 'latitude': 32.78577}}, {'path': 'design.length', 'value': {'overall': 40}}, {'path': 'atonType', 'value': {'id': 9, 'name': 'Beacon, Cardinal N'}}, {'path': 'design.beam', 'value': 60}, {'path': 'virtual', 'value': False}, {'path': 'offPosition', 'value': True}, {'path': '', 'value': {'mmsi': '105103837'}}, {'path': 'sensors.ais.class', 'value': 'ATON'}], '$source': 'can0.c03282004a6ea6f0'}"

        await websocket.send(sampleAton)
        print("\n sent >>",sampleAton)
        message = await websocket.recv()
        print(f'\n recv << message')

asyncio.run(hello("ws://localhost:3000/signalk/v1/stream?subscribe=none"))

The new AtoN does not show on OpenCPN or other attached plotters.

Scott Bender•4mo ago

Name is not formed correctly Anything in the Data Browser? Let me see if I can find a good example…

AlienTechnologyOP•4mo ago

Yes, I see both in data browser. Maybe I don't have forwarding correct. An example would be awesome as well. Thank you!!

Scott Bender•4mo ago

{
    "updates": [
      {
        "values": [
          {
            "path": "",
            "value": {
              "name": "SW"
            }
          },
          {
            "path": "navigation.position",
            "value": {
              "longitude": -76.3847132,
              "latitude": 38.99384
            }
          },
          {
            "path": "atonType",
            "value": {
              "id": 13,
              "name": "Beacon, Port Hand"
            }
          },
          {
            "path": "virtual",
            "value": true
          },
          {
            "path": "offPosition",
            "value": false
          },
          {
            "path": "",
            "value": {
              "mmsi": "993672315"
            }
          },
          {
            "path": "sensors.ais.class",
            "value": "ATON"
          }
        ]
      }
    ],
    "context": "atons.urn:mrn:imo:mmsi:993672315"
  }

{
    "updates": [
      {
        "values": [
          {
            "path": "",
            "value": {
              "name": "SW"
            }
          },
          {
            "path": "navigation.position",
            "value": {
              "longitude": -76.3847132,
              "latitude": 38.99384
            }
          },
          {
            "path": "atonType",
            "value": {
              "id": 13,
              "name": "Beacon, Port Hand"
            }
          },
          {
            "path": "virtual",
            "value": true
          },
          {
            "path": "offPosition",
            "value": false
          },
          {
            "path": "",
            "value": {
              "mmsi": "993672315"
            }
          },
          {
            "path": "sensors.ais.class",
            "value": "ATON"
          }
        ]
      }
    ],
    "context": "atons.urn:mrn:imo:mmsi:993672315"
  }

your position data is wrong too (and yes, it's not really strait forward!)

AlienTechnologyOP•4mo ago

I will base my request on your example. In the docs at https://signalk.org/specification/1.7.0/doc/request_response.html#websockets-and-other-full-duplex-protocols, it talks about a response to a websocket request. Should I not expect one?

Scott Bender•4mo ago

No, won't get a response for sending deltas

AlienTechnologyOP•4mo ago

How about full requests?

Scott Bender•4mo ago

what do you mean "full reuest"?

AlienTechnologyOP•4mo ago

Don't deltas just modify a previously sent packet?

Scott Bender•4mo ago

no...

AlienTechnologyOP•4mo ago

So if only the position changed, I could send that but not virtual, name, etc.

Scott Bender•4mo ago

yes as long as the "context" is the same

AlienTechnologyOP•4mo ago

Ok, that makes sense. Is there a way to ensure that SK got the request?

Scott Bender•4mo ago

not really, you can assume it got it as long as you don't get any errors from the websocket libraries

AlienTechnologyOP•4mo ago

Gotcha. I can't thank you enough for the help. Thanks.

Scott Bender•4mo ago

ur welcome! oh, didn't think of this before, but there's a way to make a python plugin. then you don't have to worry about managing a websocket and the python process.

Scott Bender•4mo ago

https://github.com/SignalK/sk-plugin-python-demo

GitHub

GitHub - SignalK/sk-plugin-python-demo: Demonstration of a SK serve...

Demonstration of a SK server plugin in Python. Contribute to SignalK/sk-plugin-python-demo development by creating an account on GitHub.

AlienTechnologyOP•3mo ago

Awesome. I'll look into it. My marks are showing up on OpenCPN and a Raymarine MFD. Just have to figure out why the Garmin is being stubborn. But that's not a SK issue. Thanks again. Where is the best place to look for the SK data model? I looked through the documentation but didn't see anything describing what to send for PGN 129041 - Aids to Navigation Report. Looking for Position Accuracy and AIS Transeiver Info.

Gaming

Programming

Possible to create AtoNs with SignalK API?