Dunno if this will help, but see Bernard Liengme's
http://www.stfx.ca/people/bliengme/E...UnderCurve.htm and
http://www.stfx.ca/people/bliengme/E...olygonArea.htm

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Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions

In article ,
says...
I have plotted data values (z axis) based on cartesion coordinate location (x
axis and y axis) as a 3D surface chart and then changed the elevation to 90
degrees to get a topographical/isobar representation of the data. Is it
possible to get the area contained within the isobar lines? If Excel can't
do this is there an add-in or another product that can do this?