Graph Panel - renaming numbers to strings from single metric


I have a elastic DB which has a field called Application, the values in application field are numbers
1,4,5,67,80 etc
each value means a application name 1=http, 4=dns, 67=dhcp etc
I would like to map these values to strings in Graph Panel, I see this option in Table panel but not in Graph Panel, is there a way to do this ?
I can define a keyword filed in elastic db and do conversion but don’t want to do it since the strings in db occupy too much space for each record
I tried using Alias function but no luck


I discovered that i can use filter by, but that’s static, I don’t have control over to show the top 10 by a metric over time automatically every time