winnow/lib/normalize-query-options/geometry-filter.js

Apply sql-like filters to GeoJSON

const _ = require('lodash')
const { normalizeArray } = require('./helpers')
const { arcgisToGeoJSON } = require('@terraformer/arcgis')
const bboxPolygon = require('@turf/bbox-polygon').default
const projectCoordinates = require('../helpers/project-coordinates')
const normalizeGeometryFilterSpatialReference = require('./geometry-filter-spatial-reference')
const normalizeSourceSR = require('./source-data-spatial-reference')

function normalizeGeometryFilter (options = {}) {
  const geometry = options.geometry || options.bbox

  if (!geometry) return

  const geometryFilterSpatialReference = normalizeGeometryFilterSpatialReference(options)
  const fromSR = getCrsString(geometryFilterSpatialReference)

  const geometryFilter = transformGeometryToGeojson(geometry)

  const dataCrs = normalizeSourceSR(options)

  const toSR = getCrsString(dataCrs)

  if (fromSR === toSR) {
    return geometryFilter
  }

  geometryFilter.coordinates = projectCoordinates({
    coordinates: geometryFilter.coordinates,
    fromSR,
    toSR
  })

  return geometryFilter
}

function transformGeometryToGeojson (geometry) {
  if (_.isString(geometry) || Array.isArray(geometry)) {
    const coordinates = normalizeArray(geometry)

    if (coordinates.length === 2) {
      return {
        type: 'Point',
        coordinates: coordinates.map(Number)
      }
    }

    const { geometry: polygon } = bboxPolygon(coordinates)
    return polygon
  }

  if (geometry.xmin || geometry.xmin === 0) {
    return transformEsriEnvelopeToPolygon(geometry)
  }

  if (geometry.x || geometry.rings || geometry.paths || geometry.points) {
    return arcgisToGeoJSON(geometry)
  }
  return geometry
}

function transformEsriEnvelopeToPolygon ({ xmin, ymin, xmax, ymax }) {
  return {
    type: 'Polygon',
    coordinates: [[
      [xmin, ymin],
      [xmax, ymin],
      [xmax, ymax],
      [xmin, ymax],
      [xmin, ymin]
    ]]
  }
}

function getCrsString ({ wkt, wkid } = {}) {
  return wkt || `EPSG:${wkid}`
}

module.exports = normalizeGeometryFilter