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dma-ais / AisLib

DMA AisLib - Java library for handling AIS messages
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Message Type 25 Not Implemented #65

Open michaeljfazio opened 4 years ago

michaeljfazio commented 4 years ago

I'm processing a satellite AIS feed (global coverage) and quite often we receive AIS Message 25 which fails to parse with an exception. Given that this is a valid AIS Message type I would think it should probably be implemented (unless there is a good reason not to).

tbsalling commented 4 years ago

I am afraid that (to my knowledge) there's no current funding or maintenance of this project. I hope that this will improve in the future - but for now it's a bit of a DIY project.

If you can submit a pull request for decoding of message type 25 I'll be happy to merge it though.

mith-emsa commented 5 months ago

@michaeljfazio we have been looking at the issues reported for the AIS decoding library, I see this quite old issue raised by you. However according to the AIS specs, message type 25 is used to transmit binary data from one device to another. Therefore there is no standard to decode this message. What would be the idea that you had to parse this message? It seems that there would be no data structure to derive from this binary data message which is not a standard. Thanks in advance for your clarification.

michaeljfazio commented 5 months ago

I would think a message type with just a raw byte array would be sufficient @mith-emsa.

tbsalling commented 5 months ago

That’s how my alternative (decoding only) library AISmessages does it. So maybe that could be for inspiration?

https://github.com/tbsalling/aismessages/blob/0222c224b52d09ad5c0af5e208f0379dbf7e0f42/src/main/java/dk/tbsalling/aismessages/ais/messages/BinaryMessageSingleSlot.java#L76

ED-account commented 3 months ago

@michaeljfazio We have determined that AisLib can be extended to the extent of decoding AIS Single Slot Binary Messages (Message 25) into a binary array. However, the extraction of the meaningful payload will need to be handled by the API utilizing AisLib. This is because Message 25 is an Application Specific Message, since the data content of this binary message is defined by the application.

We are looking at implementing the feature for the future but without a planned date for implementation.