added check if dataframe is not empty to Empower force curve

rowers/interactiveplots.py

@@ -154,6 +154,8 @@ def interactive_forcecurve(theworkouts,workstrokesonly=False):
 	except KeyError:
 	    pass
 
+    if rowdata.empty:
+	return "","No Valid Data Available","",""
     
     catchav = rowdata['catch'].mean()
     finishav = rowdata['finish'].mean()
@@ -348,7 +350,7 @@ def interactive_forcecurve(theworkouts,workstrokesonly=False):
     slider_spm_max = Slider(start=15.0, end=55,value=55.0, step=.1,
 		title="Max SPM",callback=callback)
     callback.args["maxspm"] = slider_spm_max
-    
+
     distmax = 100+100*int(rowdata['distance'].max()/100.)
     
     slider_dist_min = Slider(start=0,end=distmax,value=0,step=1,
@@ -386,6 +388,9 @@ def interactive_histoall(theworkouts):
     rowdata = dataprep.getsmallrowdata_db(['power'],ids=ids,doclean=True)
     rowdata.dropna(axis=0,how='any',inplace=True)
 
+    if rowdata.empty:
+	return "","No Valid Data Available","",""
+
     histopwr = rowdata['power'].values
     if len(histopwr) == 0:
         return "","No valid data available","",""