Show direction of linestring on map - auto zoom on map

Question

I have this code, which plots on a map a linestring which is the track of 2 coordinate points that the user supplies.

public class Quickstart {

public static void main(String[] args) throws Exception {
    // display a data store file chooser dialog for shapefiles
    File file = JFileDataStoreChooser.showOpenFile("shp", null);
    if (file == null) {
        return;
    }

    FileDataStore store = FileDataStoreFinder.getDataStore(file);
    SimpleFeatureSource featureSource = store.getFeatureSource();

  GeometryFactory gf = JTSFactoryFinder.getGeometryFactory();

  double latitude, longitude, latitudeDest, longitudeDest;
  Scanner reader = new Scanner(System.in);
  reader.useLocale(Locale.US);
  System.out.println("Enter reference longitude and latitude:
");
  longitude = reader.nextDouble();
  latitude = reader.nextDouble();
  System.out.println("Enter destination longitude and latitude:
");
  longitudeDest = reader.nextDouble();
  latitudeDest = reader.nextDouble();
  reader.close();

    final String EPSG4326 = "GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG"," +
            ""7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree", " + 
            "0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]";
    CoordinateReferenceSystem crs = CRS.parseWKT(EPSG4326);        


    Point start = gf.createPoint(new Coordinate(longitude, latitude));
    Point end = gf.createPoint(new Coordinate(longitudeDest, latitudeDest));

    GeodeticCalculator gc = new GeodeticCalculator(crs);
    gc.setStartingPosition(JTS.toDirectPosition(start.getCoordinate(), crs));
    gc.setDestinationPosition(JTS.toDirectPosition(end.getCoordinate(), crs));

    // Calculate distance between points
    double distance = gc.getOrthodromicDistance();

    int totalmeters = (int) distance;
    int km = totalmeters / 1000;
    int meters = totalmeters - (km * 1000);
    float remaining_cm = (float) (distance - totalmeters) * 10000;
    remaining_cm = Math.round(remaining_cm);
    float cm = remaining_cm / 100;

    System.out.println("Distance = " + km + "km " + meters + "m " + cm + "cm");

    Coordinate[] coordinates = {start.getCoordinate(), end.getCoordinate()};       
    LineString line = gf.createLineString(coordinates);

    SimpleFeatureTypeBuilder builder = new SimpleFeatureTypeBuilder();
    builder.setName("TwoDistancesType");
    builder.setCRS(DefaultGeographicCRS.WGS84);
    //builder.add("start", Point.class);
    //builder.add("end", Point.class);
    builder.add("line", LineString.class);
    // build the type
    final SimpleFeatureType TYPE = builder.buildFeatureType();

    SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);
    featureBuilder.add(line);

    SimpleFeature feature = featureBuilder.buildFeature(null);
    DefaultFeatureCollection featureCollection = new DefaultFeatureCollection("internal", TYPE);
    featureCollection.add(feature);

    // Create style for the line
    //Style style = SLD.createSimpleStyle(TYPE, Color.red);
    Style style = SLD.createLineStyle(Color.red, 2.0f);
    Layer layer = new FeatureLayer(featureCollection, style);

    // Create style for the file
    Style shpStyle = SLD.createSimpleStyle(TYPE, Color.blue);
    Layer shpLayer = new FeatureLayer(featureSource, shpStyle);

    // Create a map content and add our shapefile to it
    MapContent map = new MapContent();
    map.setTitle("TEST");
    map.addLayer(layer);
    map.addLayer(shpLayer);

    // Now display the map
    JMapFrame.showMap(map);


}

I have 2 questions:

1) How can I show the direction of the line?From start point to end?

2) When you run the program and see the map , you must manually search for the linestring(red line) and then zoom to map in order to find it.Is there a way to automatically zoom to the line (the coordinates) when the map appears?

Show direction of linestring on map - auto zoom on map

1 Answers