how to draw (x,y.z) point without binning x and y ?

Dear rooters,

I want to draw a graph for a group of 3-D data (x,y,z) in which the x and y values are not binned, i.e. the point in x-y plane is exactly a point. And moreover, the z are binned with 5 bins and in each bin the point is displayed by a specific color.

How can I do that ?

I can only think of TH2F and use SetBinContent. But the effect is not so satisfactory.

Thanks in advance !

Best Regards,
Xianguo

-- 
Take flight into the sky, beyond the moon, beyond my mind.

Xianguo LU
Physics Department, Peking University
Beijing, China
Tel: 0086-10-62753888(o)