anchor.diff: -
   
   library trails;
   
  
positive.code:     
    }
    
  }
negative.code:           .then((_) {
              return TraceAnalysis.fromGpxFile(file).then((traceAnalysis){
                
                TraceAnalysis purgeTraceAnalysis = traceAnalysis.computeNewPurgedTraceAnalysis(idealMaxPointNumber: 3500);
                
                Trace trace = new Trace.fromTraceAnalysis(user.login, purgeTraceAnalysis); 
                trace.title = title ;
  