examples/java-spark-sql/src/main/java/spark/GeoParquetAccessor.java

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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
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package spark;

import java.util.List;
import org.apache.sedona.core.spatialOperator.RangeQuery;
import org.apache.sedona.core.spatialOperator.SpatialPredicate;
import org.apache.sedona.core.spatialRDD.SpatialRDD;
import org.apache.sedona.sql.utils.Adapter;
import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.SparkSession;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geom.Polygon;

public class GeoParquetAccessor {

  private final SparkSession session;
  private String parquetPath;

  public GeoParquetAccessor() {
    this.session = new SedonaSparkSession().getSession();
    this.parquetPath = "";
  }

  // Overload with constructor that has Spark session provided
  // Use to avoid error - can't have two SparkContext objects on one JVM
  public GeoParquetAccessor(SparkSession session, String parquetPath) {
    this.session = session;
    this.parquetPath = parquetPath;
  }

  public List<Geometry> selectFeaturesByPolygon(
      double xmin, double ymax, double xmax, double ymin, String geometryColumn) {

    // Read the GeoParquet file into a DataFrame
    Dataset<Row> insarDF = session.read().format("geoparquet").load(parquetPath);

    // Convert the DataFrame to a SpatialRDD
    // The second argument to toSpatialRdd is the name of the geometry column.
    SpatialRDD<Geometry> insarRDD = Adapter.toSpatialRdd(insarDF, geometryColumn);

    // Define the polygon for the spatial query
    GeometryFactory geometryFactory = new GeometryFactory();
    Coordinate[] coordinates =
        new Coordinate[] {
          new Coordinate(xmin, ymin),
          new Coordinate(xmax, ymin),
          new Coordinate(xmax, ymax),
          new Coordinate(xmin, ymax),
          new Coordinate(xmin, ymin) // A closed polygon has the same start and end coordinate
        };
    Polygon queryPolygon = geometryFactory.createPolygon(coordinates);

    // Perform the spatial range query
    // This will return all geometries that intersect with the query polygon.
    // Alternatives are SpatialPredicate.CONTAINS or SpatialPredicate.WITHIN
    SpatialRDD<Geometry> resultRDD = new SpatialRDD<>();
    try {
      resultRDD.rawSpatialRDD =
          RangeQuery.SpatialRangeQuery(insarRDD, queryPolygon, SpatialPredicate.INTERSECTS, false);
    } catch (Exception e) {
      e.printStackTrace();
    }

    // Collect the results back to the driver
    return resultRDD.getRawSpatialRDD().collect();
  }
}