You can't get a true X-Y-Z contour chart; Excel's contour chart is pretty rudimentary.
Set up your data like this:
Y1 Y2 Y3 Y4
X1 Z11 Z12 Z13 Z14
X2 Z21 Z22 Z23 Z24
X3 Z31 Z32 Z33 Z34
X4 Z41 Z42 Z43 Z44
The top left cell should be blank. Select the range and start the chart wizard.
I've found that the shape of the contour chart is not very good, particularly if you have saddle
points. Say two diagonally opposed points have high values of 5 and the other two have low
values of 1. A true rendering of the saddle point would give you a value around 3 in the middle,
but Excel draws a straight line at 5 connecting the two high points, then slopes the sides down
to 1. The effect is more of a rooftop than a saddle.
If I really need this kind of chart, I insert a row between each row of data, and a column
between each column of data, then use formulas or eyeball to interpolate the values of these
inserted cells. A lot of work for so-so results.
- Jon
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Jon Peltier, Microsoft Excel MVP
Peltier Technical Services
Tutorials and Custom Solutions
http://PeltierTech.com/
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