https://github.com/derhuerst/osm-flatten-relation

Resolve an OpenStreetMap relation recursively.
https://github.com/derhuerst/osm-flatten-relation

openstreetmap osm

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Resolve an OpenStreetMap relation recursively.

• Host: GitHub
• URL: https://github.com/derhuerst/osm-flatten-relation
• Owner: derhuerst
• License: isc
• Created: 2016-05-14T14:02:58.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2023-05-30T17:03:32.000Z (over 1 year ago)
• Last Synced: 2024-12-21T21:37:26.149Z (21 days ago)
• Topics: openstreetmap, osm
• Language: JavaScript
• Homepage: https://github.com/derhuerst/osm-flatten-relation
• Size: 49.8 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • License: license.md

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README

        
# osm-flatten-relation

**Resolve an [OpenStreetMap](http://www.openstreetmap.org) relation recursively.**

[![npm version](https://img.shields.io/npm/v/osm-flatten-relation.svg)](https://www.npmjs.com/package/osm-flatten-relation)

![ISC-licensed](https://img.shields.io/github/license/derhuerst/osm-flatten-relation.svg)

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## Installing

```

npm install osm-flatten-relation

```

## Usage

From the command line:

```

osm-flatten-relation 2679163 >nodes.ndjson

```

As a JavaScript library:

```js

import {flattenOsmRelation as flatten} from 'osm-flatten-relation'

flatten(relation, concurrency = 4, retries = 3)

.on('stats', (stats) => console.log(stats))

.on('relation', (relation) => console.log('relation', relation.id))

.on('way', (way) => console.log('way', way.id))

.on('node', (node) => console.log('node', node.id))

// .on('data', console.log)

.on('error', console.error)

```

`flatten` returns a [readable stream](https://nodejs.org/api/stream.html#stream_class_stream_readable) of a [relation](http://wiki.openstreetmap.org/wiki/Elements#Relation)'s [ways](http://wiki.openstreetmap.org/wiki/Elements#Way) and [nodes](http://wiki.openstreetmap.org/wiki/Elements#Node). It will also emit the events `relation`, `way` and `node` whenever it fetched data.

*Note*: With `concurrency > 1`, nodes will *not* be emitted in breadth-first order anymore.

### Example

To get all nodes of [*U-Bahnlinie U6: Alt-Mariendorf => Alt-Tegel*](http://www.openstreetmap.org/relation/2679163) with a `concurrency` of `5` requests:

```js

import {flattenOsmRelation as flatten} from 'osm-flatten-relation'

flatten(2679163, 5)

.on('data', console.log)

.once('erorr', (err) => {

	console.log(err)

	process.exit(1)

})

```

```js

{id: 3043920508, latitude: 52.439691,  longitude: 13.3877031}

{id: 31034998,   latitude: 52.4537104, longitude: 13.3843233}

// …

{id: 1688279730, latitude: 52.439011,  longitude: 13.3878563}

```

## Contributing

If you **have a question**, **found a bug** or want to **propose a feature**, have a look at [the issues page](https://github.com/derhuerst/osm-flatten-relation/issues).