Reproject features with geotools

Question

is there a way to reproject a feature collection into a new one with another coordinate reference system? I am trying to achieve this by using geotools's reprojector:

SimpleFeatureSource featureSource = ...
SimpleFeatureCollection sfc = new ReprojectingFeatureCollection(featureSource.getFeatures(),
    org.geotools.referencing.CRS.decode("EPSG:4326"));

sfc presents another schema's CRS but its geometries looks the same before reprojecting. What am I missing? Do I have to manually create a new geometry with desired CRS and coordinates for each geometry in featureSource or geotools offer a more elegant and efficient way to do this? I am using geotools version 17.2.

Answer 1

This code works for me:

public static void main(String[] args) throws IOException, NoSuchAuthorityCodeException, FactoryException {
     if(args.length==0) {
       System.err.println("usage: Reprojector shapefile.shp");
       System.exit(1);
     }
     FileDataStore ds = FileDataStoreFinder.getDataStore(new File(args[0]));
     SimpleFeatureCollection features = ds.getFeatureSource().getFeatures();
     try(SimpleFeatureIterator itr=features.features()){
       int count=0;
       while(itr.hasNext()&&count++<10) {
         System.out.println(((Geometry) itr.next().getDefaultGeometry()).getCentroid());
       }
     }
     System.out.println("");
     ReprojectingFeatureCollection rfc = new ReprojectingFeatureCollection(features, CRS.decode("epsg:3875"));
     try(SimpleFeatureIterator itr=rfc.features()){
       int count=0;
       while(itr.hasNext()&&count++<10) {
         System.out.println(((Geometry) itr.next().getDefaultGeometry()).getCentroid());
       }
     }
  }

giving this output:

POINT (-69.97420075028728 12.516935269076281)
POINT (66.00844744953935 33.836266910437075)

POINT (7865991.086526802 4801048.897930129)
POINT (4827402.208410819 25805775.61452194)