Current country info lookup - how to store data?

[hoeken]

I'm working on a general purpose plugin to lookup info based on your current position. The first one I'm doing is country. I'm using this npm module: https://github.com/simonepri/country-iso

That module can return a few different types of results:

// Query a point in Italy.
countryIso.get(41.9028, 12.4964);
// => ['ITA']

// Query a disputed country.
countryIso.get(24, -14);
// => ['ESH', 'MAR']

// Query a point somewhere in Atlantic Ocean.
countryIso.get(40, -40);
// => []

My main question is should I store the result as json, or should I just grab the first country and store that as a string? I'm kinda inspired here by the various utility plugins like signalk-autostate and derived-data that provide useful data that other plugins and code like node-red can use. It it worth pushing a little bit more complexity on to the user when 99% of the time it will be an array of 1 or nothing?

The second question is what path to use? I was thinking navigation.country and navigation.countryISO if I go the single route, or if I go the data route, just put the json array in navigation.country eg. [{"iso":"VCT","name":"Saint Vincent and the Grenadines"}]

After this simple one, I want to expand into different things like maritime regions and place names from this site: https://www.marineregions.org/downloads.php That will be a bit more work though and I want to see how this works first.

[hoeken]

BTW, the current plugin code is here: https://github.com/hoeken/signalk-location-info

[hoeken]

I'm leaning towards storing the json directly since its pretty simple and easy to parse. I played around with it, and its even pretty easy to pull out the country in Grafana. Its also really easy to use that json in node-red and through something like the get api.

One neat little demo I made was a web app page that is part of the plugin that you can embed which will show you the map of the country you are currently in. Would make a handy little addition to a dashboard if you cant remember what courtesy flag you should put up.

[tkurki]

And as to where to store the data file if you need one see https://github.com/SignalK/signalk-server/blob/master/SERVERPLUGINS.md#appgetdatadirpath

[mairas]

That's a nice, simple idea for a plugin! I, too, would provide the full array. Some parsing is required in any case (no country vs 1 country), so the array really doesn't change things that much. In practice, I'm not sure it makes much of a difference, though. I'd assume locations with territorial water disputes are quite rare, and most sailors would want to keep away from them. :-)

Some ideas I immediately had:

• Include exclusive economic zones. Would require additional data not provided by the reverse geocoding module you mentioned.
• Provide distance and direction to the nearest territorial waters. Would require access to raw map data as well as some great-circle distance calculations.

[hoeken]

Thanks :) It looks like I will stick with the json style then. The next step is definitely the EEZ data. That marineregions.org has a ton of this data freely available and its all in the 'geopackage' format which does have an npm library. It's going to require a bit more work, but I'll get there.

The nice thing is that all this stuff is offline, so it will work offshore when you are least likely to have internet. :)

[mairas]

Yeah, working offline is the major selling point here!