This is not such a simple problem that it may seem.
First of all, you need to totally isolate the analysis of data, and charts, data presentation. Data presentation should only be used as output, never be a source of data. So, let's forget about charts and focus on data.
I don't know the semantic of your data; it does not really matter. For a minute, let's imaging this is some statistical distribution. Even if it is not, you could possibly use the algorithms developed for statistics. Then the peak could be called a
mode of distribution:
http://en.wikipedia.org/wiki/Mode_%28statistics%29[
^].
Your case would be the case of
multi-modal distribution:
http://en.wikipedia.org/wiki/Multimodal_distribution[
^].
The problem appears to be more complex because you don't provide any assumption on the function describing your sample data. In general case, the problem is quite difficult. Please see:
Please see:
http://www.itwm.fraunhofer.de/fileadmin/ITWM-Media/Abteilungen/BV/Pdf/wirjadi08-branch-and-bound.pdf[
^],
http://www.stat.tamu.edu/~jchown/NKCreport.pdf[
^],
http://books.google.com/books?id=QKxmYCgHn20C&pg=PA58&lpg=PA58&dq=algorithm+find+modes+of+%22multimodal+distribution%22&source=bl&ots=8MVmMHxT-a&sig=avQVC8T-tRwHS3YS6zi76rAVa0w&hl=en&sa=X&ei=X9YgU5n0Nabx0gGhrIDgDg&ved=0CEwQ6AEwBQ#v=onepage&q=algorithm%20find%20modes%20of%20%22multimodal%20distribution%22&f=false[
^],
http://books.google.com/books?id=uY-Z3vORugwC&pg=PA54&lpg=PA54&dq=algorithm+find+modes+of+%22multimodal+distribution%22&source=bl&ots=QKu8TbTVz6&sig=glZ6BiCjdbXrV_HzVpPDyJL1biw&hl=en&sa=X&ei=X9YgU5n0Nabx0gGhrIDgDg&ved=0CLIBEOgBMBI#v=onepage&q=algorithm%20find%20modes%20of%20%22multimodal%20distribution%22&f=false[
^],
http://www.peerevaluation.org/data/bbf94b34eb32268ada57a3be5062fe7d/tbme-SShahid-2026734-proof.pdf[
^].
See also this short reviews of available approaches to general pike detection:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2631518[
^].
Probably, the solution for some special cases would be much easier. For example, maybe your pikes are thing and well isolated; then you could think of something pretty simple, perhaps heuristic.
—SA