advisory-circular/README.md

# Advisory Circular

This is a twitter bot that alerts you when any aircraft is circling.
You can see it in action at
[@SkyCirclesLA](https://twitter.com/SkyCirclesLA).

![Example tweet](Screen Shot 2019-12-13.png?raw=true "Example tweet")


## Prerequisites to running the bot

**Set up a Pelias instance containing information for the geographical
area you're interested in.** See https://github.com/pelias/docker and
if you're lucky the `projects` folder will have a predefined project
that covers the area you want. I run one using the `los-angeles-metro`
project.

**Get an API key for adsbexchange.com.** See
https://www.adsbexchange.com/data/ If you have a receiver and feed
them data, they'll give you a key for free. Alternately, find another
data source of realtime (or not) aircraft data and massage it into a
form that the bot can work with.

**Get access keys for a twitter account.** Follow the [instructions at
botwiki](https://botwiki.org/tutorials/how-to-create-a-twitter-app/).


## Running the bot

Put your adsbexchange.com API key and twitter keys in `secrets.yaml`.

Create an initial history database:

`echo '{}' > advisory-circular.db`

Install node dependencies:

`npm install`

Compile the clojurescript:

`npx shadow-cljs compile script`

Run the bot:

`node out/script.js --url https://adsbexchange.com/api/aircraft/json --lat <lat> --lon <lon> --radius <radius>;`

Specify your geographical region of interest by specifying a circle at
`<lat>`, `<lon>` with a radius of `<radius>` miles.

The bot will run once. The adsbexchange.com API only provides
instantaneous positions, so the bot will have to run many times and
collect some history before it's able to detect any circles.

```
while :
do
  node out/script.js --url https://adsbexchange.com/api/aircraft/json --lat <lat> --lon <lon> --radius <radius>
  sleep 10
done
```

* **Do not run the script with a large radius, or adsbexchange.com will
  ban your IP.** I use a radius of 40 miles.

* **Do not run the script more ofen than once every 10 seconds, or
  adsbexchange.com will ban your IP.**


## To do

- [ ] If we don't have neighbourhood or locality (just county), try to
      use the locality of a nearby venue. E.g. "2 miles from
      Glendale."
- [ ] Solve the issue of needing a differently sized buffer zone for
      different airports--2 miles distance from LAX is still
      practically inside the aiport. Add list with custom airport
      coords and radii? Get access to OSM polygons and compute our own
      distances?
- [ ] Lookup registration info. Possible sources: FAA,
      adsbexchange.com, janky-ass basestation.sqb's that have been
      passed around for a decade.
- [ ] Add type information to tweet status, e.g. "Eurocopter AS350".
- [ ] Use Wikipedia graph to rank landmarks? More inbound links to a
      page means it has higher significance?
- [ ] Add support for Mastodon/ActivityPub.
- [ ] Generate our own maps instead of using adsbx's? The adsbx map
      isn't always in sync with the data from the API.
- [ ] Run at global scale!