prototype history page

rowers/interactiveplots.py

@@ -172,6 +172,8 @@ from rowers.dataprep import timedeltaconv
 from math import pi
 
 def interactive_hr_piechart(df,rower,title):
+    if df.empty:
+        return "","Not enough data to make a chart"
 
     df.sort_values(by='hr',inplace=True)
     qry = 'hr < {ut2}'.format(ut2=rower.ut2)