osm-is-area

determine if an OpenStreetMap entry is an area or not.

this package uses osm-polygon-features to determine if some closed ways should be treated as polygons or lines.

example

var osmIsArea = require('osm-is-area')

// first and last ref match, but { highway: 'service' } is not an area:

console.log(osmIsArea({
  type: 'way',
  id: 4421943,
  tags: { highway: 'service' },
  refs: [ 27119458, 1764217171, 27119461, 1069372913,
    1764230257, 5530415689, 1764230254, 27119458]
})) // false


// first and last ref match; { waterway: 'riverbank' } is a valid area:

console.log(osmIsArea({
  type: 'way',
  id: 23873915,
  tags: { waterway: 'riverbank' },
  refs: [ 3584796914, 4856390070, 4856390069, 4856390067, 258759210, 997025704, 997024369, 3584796914 ]
})) // true

// first and last ref don't match - not a closed way:

console.log(osmIsArea({
  type: 'way',
  id: 4421935,
  tags: { highway: 'primary', surface: 'asphalt' },
  refs: [ 746891652, 408306337, 27119389, 1687103099, 730024891, 1035333171, 746891666 ]
})) // false

// first and last ref match; { natural: 'wood' } is a valid area:

console.log(osmIsArea({
  type: 'way',
  id: 23874706,
  tags: { name: 'Щербачевский лес', natural: 'wood' },
  refs: [ 1125622707, 1007659859, 1125622501, 1125622605, 1125622588, 1007659898, 1125622707 ]
})) // true

// first and last ref match; { boundary: 'protected area' } is a valid area:

console.log(osmIsArea({
  type: 'way',
  id: 34333478,
  tags: { name: 'Лісовий заказник «Григорівський бір»', boundary: 'protected_area' },
  refs: [ 393849373, 1010883354, 1010883623, 393849376, 1010883341, 393849377, 393849373 ]
})) // true

to try this example on your own machine, clone this repository, navigate to the directory you cloned into, and run npm run example.

api

var osmIsArea = require('osm-is-area')

osmIsArea(entry)

takes an osm entry object and returns true or false.

input osm objects should be formatted as osm-pbf-parser returns them. specifically, this module expects:

• type - a string specifying 'node', 'way', or 'relation'
• tags - an object mapping osm tag keys to values
• refs - an array of osm id's as numbers (only relevant for ways)
• members - an array of member objects (only relevant for relations)

the only thing that's relevant about the members array is whether it's empty (module will return false if this is the case).

this module assumes that all relations of type 'multipolygon' are areas, and that no other relations are areas. learn more about relation:multipolygon.

license

MIT