Adding series labels

strewart · #1 06-29-2009, 10:01 PM

Hi guys. I am producing scatter plots on Excel 2007 of spectroscopy data, in these plots it is quite important to know the peak values. Not so much y, but definitely x.

I know how to add data labels, but that is no use since there are thousands of points and they just cover each other up. A plot ranging from 0-3600 may have 10-20 peaks that I am interested in, is there an easy way to get excel to just mark the peaks without filling them all in manually?

Andy Pope · #2 06-30-2009, 05:39 AM

Add another series that just plots the required peaks? Apply data labels to that series.

strewart · #3 06-30-2009, 07:47 AM

Hmm yeah that would indeed be possible, it would still mean I would have to find all the peaks manually though. Even if I did min/max functions I would need to find the range where the peak was for all the seperate peaks, and I have a lot of charts. I could resort to that, but I would prefer ot find a quicker way if there is one.

Andy Pope · #4 06-30-2009, 07:54 AM

None that I know of.
How would the chart know what as a peak and what not?

Is it possible to 'find' the peaks with formula or code?

Maybe if you posted a small example explaining how you manually determine peaks when can help speed the process.

strewart · #5 07-01-2009, 02:15 AM

By manually finding the peaks, I mean I hover the mouse over a peak and it gives the coordinates, I write them on by hand. :P

So if I have 2 series on the one chart (one representing all the data, and the other just the peaks) how do I get data labels for just the latter and not the former? As I said before, with several thousand points on the graph it seems to be overloading my computer and freezing excel when I try to click anything to do with data labels.

Andy Pope · #6 07-01-2009, 04:27 AM

Here is a small example.

Main data is 200 points.

I copied the data set and sorted on x then y values.
Only the top 10 points are plotted and have data labels enabled.

I used a dynamic named range so changing the value in C1 will alter the number of data labels displayed.

strewart · #7 07-01-2009, 08:44 PM

Wow that very cool, thanks! I'll see how it goes.

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