Hi,

I have created an example.
http://www.andypope.info/ngs/ng33.htm

There's not much in the way of explanation I'm afraid.

The formula are standard trig calcs in order to determine x and y values
for the 2nd data series.

The secondary x axis is changed to a data axis. Use right click, chart
options to get the secondary x axis displayed so you can format it.

Cheers
Andy

Gulf Stream wrote:
How can I vary the color in an area chart between positive and negative data
points. Using zero as the defining level, anything greater than zero have
one color and anything less than zero having a different color. Thank you
for your help.

--

Andy Pope, Microsoft MVP - Excel
http://www.andypope.info