joux3 / specification

Signal K is a JSON-based format for storing and sharing marine data from different sources (e.g. nmea 0183, 2000, seatalk, etc)

Signal K Specification

This repository contains the (working) specification for Signal K, defined in JSON Schema files.

Signal K

The Free and Open Source universal marine data exchange

Signal K is about publishing a common modern and open data format for marine use. A format for the modern boat, compatible with NMEA, friendly to WiFi, cellphones, tablets, and the Internet. A format available to everyone, where anyone can contribute.

Find out more at signalk.org. Then join the mailinglist by sending an email to [email protected] or follow the discussion via the Signal K Google Groups forum.

Usage

The master branch contains the latest version of the Schema. When making changes, please clone this repo to your local machine and set up a new branch (git checkout -b branch_name). Send in a pull request for every change, put it up for discussion in the mailing list and then (when a consensus has been reached) merge it into master.

The gh-pages branch contains the currently published version of the schema and specification. Documentation is generated with Gitbook and published at http://signalk.org/specification/master/. Documentation is published on the web with a single npm command:

$ npm run docs:publish

See below for details.

Gitbook Documentation

The documentation .md sources are at https://github.com/SignalK/specification/tree/master/gitbook-docs.

Requires separate installation of ebook-convert, see https://toolchain.gitbook.com/ebook.html.

• npm run docs:serve for local preview
• npm run docs:all to generate locally
• npm run docs:publish to publish in gh-pages.

Validation

Validation against Signal K schema can be done

• with a command line validator accepting JSON from stdin
• by explicitly calling validate packaged as an npm module
• by using a Chai assertion, available in the npm module

As you can see in the example below the current implementation assumes that the input is a subtree under vessels.mmsi path.

echo '{"navigation":{"courseOverGroundTru":{"value":70.1,"source":{"label":"","type":"NMEA2000","pgn":"130577","src":"160"},"timestamp":"2014-08-15-10:01:35.236"},"speedOverGround":{"value":0.01,"source":{"label":"","type":"NMEA2000","pgn":"130577","src":"160"},"timestamp":"2014-08-15-10:01:35.236"}}}' | bin/validate.js
Unknown property (not in schema):/vessels/230099999/navigation/courseOverGroundTru

var validate = require('signalk-schema').validate;
var result = validate(msg);
  result.errors.forEach(function(error) {
    console.error(error.message + ':' + error.dataPath);
  });

chai.use(require('signalk-schema').chaiModule);
tree.should.be.validSignalK;