SmokePing graphs are viewable within Observium under applicable hosts.
You need to install SmokePing onto the same machine as Observium and then use the Observium SmokePing configuration script to build your SmokePing config. Once you have it setup, start SmokePing and the graphs will begin to appear in Observium.
You need to edit/generate the SmokePing config & restart SmokePing every time you add/remove hosts, its not automated from Observium.
-Lane