Including a third variable in a point diagram by color-coding

[Celia]

I have a dataset with three variables x, y and z (They are not necessarily
functions of each other)
Is it possible to crossplot x and y in a point diagram and additionaly
indicate z by a color code? (I would then need to have an explaining color
bar or something showing the range of colors and the corresponding values)

 

[Jon Peltier]

One way to do this is using a conditional chart. Generate as many columns of
calculations as you have colors you want to use:

http://peltiertech.com/Excel/Charts/ConditionalChart1.html

- Jon