private boolean loadDataCoordinatesFromFileCache(int id)
    {
        try {
            // file name:
            String fName = DATA_CACHE_FOLDER + "/DataCoordinate_" + FESVo.getDataType(id).name() + "_ID_" + this.srdsSource.srdsSrcID;
            
            // file object:
            File file;
            
            // if id type is a trace
            if (FESVo.getDataType(id) == DataType.TRACE){
                // create a file object:
                file = new File(fName + ".FESVo");
            }
            // if id type is a horizon:
            else if (FESVo.getDataType(id) == DataType.HORIZON){
                // create a file object:
                file = new File(fName + "_prop_" + this.horizonsSourceIDs.get(id) + ".FESVo");
            }
            // otherwise, it's an error:
            else{
                System.err.println("ID is not of type TRACE or HORIZON!!");
                System.exit(0); // exit 
                return false;
            }
            
            
            // check if file exists:
            if (!file.exists()) return false;
            
            // create a buffer reader for the feature file:
            BufferedReader in = new BufferedReader(new FileReader (file));
            
            // current line:
            String line;
            
            // index:
            int i = 0;
            
            // read till end of file:
            while((line = in.readLine()) != null)
            {
                // split the line around white spaces:
                String [] subLine = line.split(":");
                
                // convert each subString into int to get x, y
                // round float values to closest int:
                int x = Math.round(Float.parseFloat(subLine[0]));
                int y = Math.round(Float.parseFloat(subLine[1]));
                
                // insert points into FESVo:
                FESVo.addDataCoordinate(x, y, id);
                
                i++;
                
            }//while
            
            // [TEST]
            String s = (i + " data coordinates of type " + FESVo.getDataType(id).name()
                    + ", id " + id
                    + ", SRDS src_id " + this.srdsSource.srdsSrcID);
            
            if (FESVo.getDataType(id) == DataType.HORIZON)
                s += ", prop_val " + this.horizonsSourceIDs.get(id);
            
            s+= " were load from cache file into FESVo.\n";
            
            System.out.println(s);
            
            // close:
            in.close();
            
            // return true indicating a successful loading:
            return true;
            
        }//try
        
        catch (IOException ex) {
            System.err.println(ex);
        }
        
        return false;
        
    }//loadDataCoordinateFromFileCache