public static int nGenerateCoords(List<Poi> oldPoiList, List<Poi> newPoiList){
		HashMap<String, Poi> newPoiMap = new HashMap<String, Poi>();
		for (Poi new_poi : newPoiList) {
			newPoiMap.put(new_poi.getId(), new_poi);
		}
		int cnt = 0;
		for(Poi old_poi : oldPoiList){
			if(!old_poi.hasCoord()){   // old POI has no coords
				Poi new_poi = newPoiMap.get(old_poi.getId());
				if(new_poi != null){   // and remains in the new quarter
					if(new_poi.hasCoord()){ // but get coordinates in the new quarter
						cnt ++;        
						System.out.println("old POI : "+ old_poi);
						System.out.println("new POI : "+ new_poi);
//						logger.info("old POI : "+ old_poi);
//						logger.info("new POI : "+ new_poi);
					}
				}
			}
			
		}
		return cnt;
	}