Finding trough points in a data series

**Sie** · 05-27-2012, 01:57 PM

Hi everyone.

I am trying to find two most significant trough values in a data series.
For finding the first one I used MIN(C6:C406), but finding second one proves to be more difficult.
I want to specify, I am don't to find the second minimum point.
If anyone has any suggestions it would be verry helpful.

I attached here a sample of my data.
In the graph you can see that there are several trough( Minimum "peak").
I can find only the most negative one.
data series.xlsx

Thank you

**FDibbins** · 05-27-2012, 02:03 PM

try...

=SMALL($C6:$C406,1)
=SMALL($C6:$C406,2)

**shg** · 05-27-2012, 02:22 PM

Your data is very quiet. In D8 and copy down,

=IF(C8=MIN(C6:C10), C8, "")

**Sie** · 05-27-2012, 02:23 PM

I tried

Please Login or Register  to view this content.

but this is giving me the second minimum point which is right next to . What I am searching is the value of second minimum trough ( negative peak) for which I think that I need to use a more complex formula.

Thank you for your fast replay.

**Sie** · 05-27-2012, 02:39 PM

Awesome, it works. I have been trying to solve this problem for a week already.
So, for finding the two trough points I used "shg" suggestion

Please Login or Register  to view this content.

and then "FDibbins" suggestions

Please Login or Register  to view this content.

Thank you and best of luck!!!

**FDibbins** · 05-27-2012, 02:50 PM

glad to help

**Sie** · 05-27-2012, 03:09 PM

Originally Posted by shg

Your data is very quiet. In D8 and copy down,

=IF(C8=MIN(C6:C10), C8, "")

shg, Is there a way to combine your formula and FDibbins formula in one, so I will get my answer in one or two cell without the need to create extra columns?

**shg** · 05-27-2012, 04:00 PM

I wouldn't; I'd plot it as a second data series to show the detected minima.

Noisier data would require a fancier approach, and you'd value the visual reinforcement.

**Sie** · 05-27-2012, 04:34 PM

Originally Posted by shg

I wouldn't; I'd plot it as a second data series to show the detected minima.

Noisier data would require a fancier approach, and you'd value the visual reinforcement.

Yes that's true it would be a nice application. But the document I posted here is a simplified version of the full document, the full document includes over 20 columns one next to another. I need for each column the two minimum peaks value and their frequency.

This situation will require me to add 20 extra columns to the document.