README.md

polyline-encoder

This library allows easy conversion of JTS geometries and WKT to Google encoded polylines. It was originally based on an implementation of the encoding algorithm by Mark Rambow, but was extended for additional functionality and Mavenization.

https://developers.google.com/maps/documentation/utilities/polylinealgorithm

Requirements

Java 11+ Maven 3+

Example usage

import com.axiomalaska.polylineencoder.EncodedPolyline;
import com.axiomalaska.polylineencoder.PolylineEncoder;
import com.axiomalaska.polylineencoder.UnsupportedGeometryTypeException;
import com.axiomalaska.polylineencoder.WktUtil;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geom.LineString;
import org.locationtech.jts.geom.Polygon;
import org.locationtech.jts.geom.PrecisionModel;
import org.locationtech.jts.io.ParseException;
import org.locationtech.jts.io.WKTReader;

public static void jtsExample() throws UnsupportedGeometryTypeException{
    GeometryFactory geomFactory = new GeometryFactory( new PrecisionModel( PrecisionModel.FLOATING ), 4326 );
    Coordinate[] coords = new Coordinate[3];
    coords[0] = new Coordinate( 0, 0 );
    coords[1] = new Coordinate( 1, 1 );
    coords[2] = new Coordinate( 2, 2 );
    LineString jtsLineString = geomFactory.createLineString( coords );

    EncodedPolyline encodedLineString = PolylineEncoder.encode( jtsLineString );    
    System.out.println( encodedLineString.getPoints() );
    System.out.println( encodedLineString.getLevels() );               
}

public static void wktExample() throws UnsupportedGeometryTypeException{
    Geometry wktPolygon = WktUtil.wktToGeom( "POLYGON (( 0 0, 0 5, 5 5, 5 0, 0 0 ))" );
	 
    EncodedPolyline encodedPolygon = PolylineEncoder.encode( wktPolygon );    
    System.out.println( encodedPolygon.getPoints() );
    System.out.println( encodedPolygon.getLevels() );               
}