public void createJsonTree () throws IOException{
		String path = "";
		String jsonString;
		jsonTree = new STRtree();
		//create folder
		try{
			new File(saveFolder).mkdirs();
		}catch(Exception e){
			System.out.println("couldnt create folder: " + e);
		}
		//read original json file to get polygons
		jsonString = GeoJsonReader.readFile2(jsonPath);    //2 if threaded file reader
		//convert String to Polygon[]
		polygons = PolygonWorker.json2polygons(jsonString);
		//write every polygon in separate json file and save envelope + path in json Tree
		for(int i=0;i<polygons.length;i++){
			path = saveFolder+"\\"+i+".json";
			if(polygons[i]!=null){
				GeoJsonWriter.writeJsonToFile(polygons[i], path, name, type, i);
				jsonTree.insert(polygons[i].getEnvelopeInternal(), path);
			}
			
		}
		jsonTree.build(); //TODO:is build necessary for RTREE?
		polygons = null;
		}