reverse_geocoder.scala

import spray.json._
import com.esri.core.geometry.Point
import com.esri.core.geometry.OperatorContains
import com.esri.core.geometry.Geometry.GeometryAccelerationDegree
import com.esri.core.geometry.SpatialReference
import com.cloudera.science.geojson._
import com.cloudera.science.geojson.GeoJsonProtocol._

class ReverseGeocoder() extends java.io.Serializable {
    // First load the GeoJSON data as a String
    val geoJSONData = scala.io.Source.fromFile("<geojson_file_name>").mkString
  
    // Parse and load the features in the GeoJSON
    val features = geoJSONData.parseJson.convertTo[FeatureCollection]
  
    /* Map each feature to a geometry
       (similar to creating a geometry column in PostGIS)
    */
    features.map(a => OperatorContains.local().accelerateGeometry(a.geometry.geometry, SpatialReference.create(4326), GeometryAccelerationDegree.enumMedium))
  
    /* Function to reverse geocode
       (similar to using ST_CONTAINS in PostGIS)
    */
    def reverseGeocode(longitude: Double, latitude: Double): Option[String] = {
        val feature: Option[Feature] = features.find(f => {f.geometry.contains(new Point(longitude, latitude))})
        return feature.map(f => { f("region_name").convertTo[String] })
    }
}