osm-p2p-observations

Indexing layer to record monitoring observations for osm-p2p-db.

This layer understands two new document types, observation and observation-link.

observation need only have lat and lon properties at minimum.

observation-link documents require an obs property (the OSM ID of the observation document) and a link property (anything you'd like, but probably the OSM ID of the node document the observation is linked to).

Stability

We're still figuring out the requirements upstream of this API, so we may make more breaking changes in the near term, but we will respect semver by incrementing the major version for each update.

Example

Create documents with osm.create():

var osmdb = require('osm-p2p')
var obsdb = require('osm-p2p-observations')
var minimist = require('minimist')
var level = require('level')

var db = level('/tmp/osm-obs.db')

var osm = osmdb('/tmp/osm.db')
var obs = obsdb({ db: db, log: osm.log })

var doc = minimist(process.argv.slice(2), {
  string: ['obs','link']
})
delete doc._

osm.create(doc, function (err, key, node) {
  if (err) console.error(err)
  else console.log(key)
})

Create normal osm-p2p types plus 'observation' to record events and 'observation-link' to link observations with other osm-p2p types:

$ node create.js --type=observation --lon=-147.93 --lat=64.51 \
  --caption='oil in the river' --category=contamination \
  --media=2016-12-02_15h24_63ec3720a6a5f.jpg
13932038153867622787
$ node create.js --type=observation --lon=-149.95 --lat=64.49 \
  --caption='pipeline break' --category=contamination \
  --media=2016-12-02_15h51_d57362a9a06e7.jpg
313578825992369305
$ node create.js --type=node --lon=-147.92 --lat=64.51
10510648254103783027
$ node create.js --type=observation-link \
  --link=10510648254103783027 --obs=13932038153867622787
4117990465324480637

Now you can list which documents are linked to each other with obs.link():

var osmdb = require('osm-p2p')
var obsdb = require('osm-p2p-observations')
var level = require('level')
var db = level('/tmp/osm-obs.db')

var osm = osmdb('/tmp/osm.db')
var obs = obsdb({ db: db, log: osm.log })

obs.links(process.argv[2], function (err, docs) {
  console.log(docs)
})

You can query by either the linked document id or the observation id:

$ node links.js 13932038153867622787
[ { key: '4117990465324480637',
    value: 
     { type: 'observation-link',
       link: '10510648254103783027',
       obs: '13932038153867622787' } } ]
$ node links.js 10510648254103783027
[ { key: '4117990465324480637',
    value: 
     { type: 'observation-link',
       link: '10510648254103783027',
       obs: '13932038153867622787' } } ]

Some documents won't be linked to anything:

$ node links.js 313578825992369305
[]

API

var obsdb = require('osm-p2p-observations')

var obs = obsdb(opts)

Create an obs instance from:

• opts.log - a hyperlog instance from an osm-p2p-db
• opts.db - a leveldb database

var stream = obs.links(id, cb)

Return a readable stream of observation-link documents that link to id.

If cb is given, collect the documents into cb(err, docs).

id can be an OSM document ID or an observation ID.

obs.ready(cb)

Calls the callback function done exactly once, when the indexer has finished indexing all documents in osmdb.

Install

npm install osm-p2p-observations

License

MIT