Charts showing x,y and z coordinates

Hi,
Is there any suitable chart which can represent the x,y,z
coordinates.
I have the following need.
X axis : Number of incidents.
Y axis : Assignment group.
Z axis : Incident by status.
I am using the Ziya chart.I found the bubble chart for representing this
situation but is there any better way for doing this?

Thank You
Savitha

may want to ask in the rails forum