some small improvments

rowers/interactiveplots.py

@@ -5092,6 +5092,8 @@ def interactive_multiple_compare_chart(ids,xparam,yparam,plottype='line',
         deltas = [pair[1]-pair[0] for key,pair in startenddict.items()]
         xaxmin = 0
         xaxmax = pd.Series(deltas).max()*1000.
+        if xaxmax == 0:
+            xaxmax = tseconds.max()
     else:
         xaxmax = datadf['distance'].max()
         xaxmin = datadf['distance'].min()
@@ -5182,21 +5184,21 @@ def interactive_multiple_compare_chart(ids,xparam,yparam,plottype='line',
 
         group.sort_values(by='time',ascending=True,inplace=True)
 
-        group['time'] = group['time'] - 1.e3*startsecond
-
-        mask = group['time'] < 0
-        group.mask(mask,inplace=True)
-        mask = group['time'] > 1.e3*(endsecond-startsecond)
-        group.mask(mask,inplace=True)
-
-
-
-
+        if endsecond > 0:
+            group['time'] = group['time'] - 1.e3*startsecond
+            mask = group['time'] < 0
+            group.mask(mask,inplace=True)
+            mask = group['time'] > 1.e3*(endsecond-startsecond)
+            group.mask(mask,inplace=True)
 
         if xparam == 'cumdist':
             group['cumdist'] = group['cumdist'] - group['cumdist'].min()
             res = make_cumvalues(group[xparam])
             group[xparam] = res[0]
+        elif xparam == 'distance':
+            group['distance'] = group['distance'] - group['distance'].min()
+
+
         try:
             group['x'] = group[xparam]
         except KeyError:

rowers/views/workoutviews.py

@@ -1542,7 +1542,11 @@ def virtualevent_compare_view(request,id=0):
 
 
     if request.method == 'GET':
-        xparam = race.sessionmode if race.sessionmode in ['distance','time'] else 'time'
+        xparam = 'time'
+        if race.sessionmode == 'distance':
+            xparam = 'cumdist'
+        
+
         yparam = 'pace'
         plottype = 'line'