overpass-frontend/src/convertFromXML.js

A JavaScript (NodeJS/Browser) library to easily access data from OpenStreetMap via Overpass API or from an OSM File. The objects can directly be used with LeafletJS or exported to GeoJSON. Data will be cached in the browser memory.

const BoundingBox = require('boundingbox')

module.exports = function convertFromXML (xml) {
  const result = {
    version: parseFloat(xml.getAttribute('version')),
    generator: xml.getAttribute('generator'),
    osm3s: {},
    elements: []
  }

  const notes = xml.getElementsByTagName('note')
  if (notes.length) {
    result.osm3s.copyright = notes[0].textContent
  }

  const metas = xml.getElementsByTagName('meta')
  if (metas.length) {
    result.osm3s.timestamp_osm_base = metas[0].getAttribute('osm_base')
    if (metas[0].hasAttribute('areas')) {
      result.osm3s.timestamp_areas_base = metas[0].getAttribute('areas')
    }
  }

  let current = xml.firstChild
  while (current) {
    const element = {}

    if (current.nodeName === 'node' || current.nodeName === 'way' || current.nodeName === 'relation') {
      element.type = current.nodeName
      element.id = parseInt(current.getAttribute('id'))
      element.changeset = parseInt(current.getAttribute('changeset'))
      element.timestamp = current.getAttribute('timestamp')
      element.user = current.getAttribute('user')
      element.uid = parseInt(current.getAttribute('uid'))
      element.version = parseInt(current.getAttribute('version'))

      if (element.type === 'node') {
        element.lat = parseFloat(current.getAttribute('lat'))
        element.lon = parseFloat(current.getAttribute('lon'))
      } else if (element.type === 'way') {
        element.nodes = []
      } else if (element.type === 'relation') {
        element.members = []
      }

      let child = current.firstChild
      while (child) {
        if (child.nodeName === 'tag') {
          if (!('tags' in element)) {
            element.tags = {}
          }

          element.tags[child.getAttribute('k')] = child.getAttribute('v')
        } else if (child.nodeName === 'member') {
          const member = {
            type: child.getAttribute('type'),
            ref: parseInt(child.getAttribute('ref')),
            role: child.getAttribute('role')
          }

          if (child.hasAttribute('lat')) {
            member.lat = parseFloat(child.getAttribute('lat'))
            member.lon = parseFloat(child.getAttribute('lon'))
          }

          let memberChild = child.firstChild
          if (member.type === 'way' && memberChild) {
            member.geometry = []
            while (memberChild) {
              if (memberChild.nodeName === 'nd') {
                member.geometry.push({
                  lat: parseFloat(memberChild.getAttribute('lat')),
                  lon: parseFloat(memberChild.getAttribute('lon'))
                })
              }

              memberChild = memberChild.nextSibling
            }
          }

          element.members.push(member)
        } else if (child.nodeName === 'nd') {
          element.nodes.push(parseInt(child.getAttribute('ref')))

          if (child.hasAttribute('lat')) {
            if (!element.geometry) {
              element.geometry = []
            }

            element.geometry.push({
              lat: parseFloat(child.getAttribute('lat')),
              lon: parseFloat(child.getAttribute('lon'))
            })
          }
        }

        child = child.nextSibling
      }

      result.elements.push(element)
    } else if (current.nodeName === 'bounds') {
      const bounds = new BoundingBox({
        minlat: parseFloat(current.getAttribute('minlat')),
        minlon: parseFloat(current.getAttribute('minlon')),
        maxlat: parseFloat(current.getAttribute('maxlat')),
        maxlon: parseFloat(current.getAttribute('maxlon'))
      })

      if (result.bounds) {
        result.bounds = result.bounds.extend(bounds)
      } else {
        result.bounds = bounds
      }
    }

    current = current.nextSibling
  }

  return result
}