What you have to do is 'merge' the x-values of the 2 data sets. In the
example below the x-values go from 10 to 40 to 10 in DataSet 1 and from
15 to 45 to 15 in DataSet2. I reorganized the data so that the 2 sets
'interleave.'

Data set 1:
10 1.061231423
20 1.861363713
30 6.561589331
40 3.4964915
40 9.683049858
30 20.00872277
20 11.95088416
10 11.62636711

Data set 2:
15 3.4709576
25 2.725999451
35 16.9991303
45 18.1101212
35 21.63843686
25 12.27002799
15 35.20802415

Merged data set:
10 1.061231423
15 3.4709576
20 1.861363713
25 2.725999451
30 6.561589331
35 16.9991303
40 3.4964915
45 18.1101212
40 9.683049858
35 21.63843686
30 20.00872277
25 12.27002799
20 11.95088416
15 35.20802415
10 11.62636711

Plot the merged data set and it will give you exactly what you want.

It isn't pretty to set up but if you have a lot of data (whether 200 is
a lot is up to you) and are comfortable with VBA you may want to
automate the process.

--
Regards,

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

In article ,
says...
I have many sets of data for which the x-values run up from approx 60 to 100,
and back down to 60ish. Each set of data consists of 200 points. I can
happily display each set individually on a scatter chart, with the categories
from, 60 (at point i=1)to 100 (i=100) to 60 (i=200). My probably occurs when
I want to display two sets of data on the same graph. For each set, the
x-values vary, for example another set could run from 65 to 95 then back to
65, but it still contains 200 points. Excel will only allow one set of values
on the category axis, so only one data set will be correctly represented by
the x-values. Using a scatter graph uses numerical x-values rather than
categories, so my x-values only go from 60ish to 100ish, which is not what i
want.

Is there any way to use numerical values on a line chart, and have each data
set represented correctly against the x-axis? Or similary can I create a
scatter graph with x-values running from 60 to 100 to 60?

Any help greatly appreciated.