Auto detect and label the peaks and botttoms of a graph?

Hello,

I was wondering if excel can auto label peaks and bottoms of a graph? Let me go further:

I have a graph that has one data number for every day of the year (365). This is a natural up and down curve, similar to a stock.

Can excel find the key high and low points? I have attached an example that I think may help. In it you will see I have quickly labeled the key tops and bottoms. CHART TEST.xlsxCHART TEST.xlsx.

I basically omitted the peaks/bottoms that are very short term and irrelevant.

Thanks so much in advance.

You should be able to do the desired auto-labeling via VBA.
As to what consitutes a Key point - that you would need to clearly define for Excel. From what I see, trend-reversal seem to be the common attribute for all key points. However, you'd need to define it in more specific terms - like percentage change, or minimum difference between two consecutive lows or highs - so they maybe labelled accordingly.

Basically, first you label all the points, and then delete the labels that do not meet the "Key" criteria.
HTH!