anchor.diff:            .then((_) {
               return TraceAnalysis.fromGpxFile(file).then((traceAnalysis){
                 
  -              TraceRawDataPurger traceRawDataPurger = new TraceRawDataPurger( 1000/12 , 4000  ) ;
  -              
  -              TraceRawData data = new TraceRawData();
  -              data.points = traceAnalysis.points ;
  -              TraceRawData purgedData = traceRawDataPurger.purge(data);
  -              TraceAnalysis purgeTraceAnalysis = new TraceAnalysis.fromPoints(purgedData);
  +              TraceAnalysis purgeTraceAnalysis = traceAnalysis.computeNewPurgedTraceAnalysis(idealMaxPointNumber: 3500);
                 
                 Trace trace = new Trace.fromTraceAnalysis(user.login, purgeTraceAnalysis); 
                 trace.title = title ;
  
positive.code: 
  
  library trails;
  
  
negative.code:     
    }
    
  }
  