Spatial lucene simple query doesn't work?

Question

Hi, does anyone have any experiences using the lucene's spatial search component (lucene 3.0)?

I tried a very simple example but could not get the search to return anything, see below for all the codes

import java.io.IOException;

import org.apache.lucene.analysis.WhitespaceAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Field.Index;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.IndexWriter.MaxFieldLength;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.spatial.tier.DistanceQueryBuilder;
import org.apache.lucene.spatial.tier.projections.CartesianTierPlotter;
import org.apache.lucene.spatial.tier.projections.IProjector;
import org.apache.lucene.spatial.tier.projections.SinusoidalProjector;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.NumericUtils;

public class SpatialLuceneExample{
    private static final String LAT_FIELD = "lat", LON_FIELD = "lon", TIER_PREFIX_FIELD = "_localTier";

    private double maxMiles = 25, minMiles = 1; // anything lower than 1 mile will just give tier 15
    // see http://www.nsshutdown.com/projects/lucene/whitepaper/locallucene_v2.html
    private IProjector projector = new SinusoidalProjector();
    private CartesianTierPlotter ctp = new CartesianTierPlotter(0, projector, TIER_PREFIX_FIELD);
    //startTier is 14 for 25 miles, 15 for 1 miles in lucene 3.0
    private int startTier = ctp.bestFit(maxMiles), endTier = ctp.bestFit(minMiles);    

    /**
     * Add the lat, lon, and tier box id to the document
     * see http://www.nsshutdown.com/projects/lucene/whitepaper/locallucene_v2.html
     * @param lat
     * @param lon
     * @param document a geo document
     */
    private void addSpatialLcnFields(double lat, double lon, Document document){
        document.add(new Field(LAT_FIELD, NumericUtils.doubleToPrefixCoded(lat), Field.Store.YES, Field.Index.NOT_ANALYZED));
        document.add(new Field(LON_FIELD, NumericUtils.doubleToPrefixCoded(lon), Field.Store.YES, Field.Index.NOT_ANALYZED));

        for(int tier = startTier ; tier<= endTier; tier++){
            CartesianTierPlotter ctp = new CartesianTierPlotter(tier, projector, TIER_PREFIX_FIELD);
            double boxId = ctp.getTierBoxId(lat, lon);
            document.add(new Field(ctp.getTierFieldName(), NumericUtils.doubleToPrefixCoded(boxId), Field.Store.YES, Field.Index.NOT_ANALYZED_NO_NORMS));
        }
    }


    private void addLocation(IndexWriter writer, String name, double lat, double lon) throws IOException{
        Document doc = new Document();
        doc.add(new Field("name", name, Field.Store.YES, Index.ANALYZED));
        doc.add(new Field("metafile", "doc", Store.YES, Index.ANALYZED));
        addSpatialLcnFields(lat, lon, doc);
        writer.addDocument(doc);
    }

    public static void main(String[] args) throws Exception{
        SpatialLuceneExample sle = new SpatialLuceneExample();
        Directory dir = new RAMDirectory();
        IndexWriter writer = new IndexWriter(dir, new WhitespaceAnalyzer(), MaxFieldLength.UNLIMITED);

        sle.addLocation(writer, "test", 39.9260, -75.1566);

        writer.commit();
        writer.close();

        IndexSearcher searcher = new IndexSearcher(dir);
        DistanceQueryBuilder dq = new DistanceQueryBuilder(39.9260, -75.1566, 10d, LAT_FIELD, LON_FIELD, true);

        Query tq = new TermQuery(new Term("metafile", "doc"));
        TopDocs hits = searcher.search(dq.getQuery(tq), 10);
        for(int i =0; i<hits.totalHits; i++){
            Document doc = searcher.doc(hits.scoreDocs[i].doc);
            System.out.println(doc.get("name"));
        }
    }
}

Any helps/comments will be greatly appreciated.

Answer 1

You need to add the tier prefix to the query builder:

    DistanceQueryBuilder dq = new DistanceQueryBuilder(coord.getLat(),
            coord.getLon(), miles, Spatial.LAT_FIELD, Spatial.LON_FIELD,
            Spatial.TIER_PREFIX_FIELD, false);