+ Reply to Thread
Results 1 to 6 of 6

Data Smoothing

  1. #1
    Registered User
    Join Date
    11-19-2013
    Location
    United Kingdom
    MS-Off Ver
    Excel 2011 (Mac)
    Posts
    3

    Data Smoothing

    Hi!

    I was wondering if anybody could help out with data smoothing functions within excel.

    On the attached .xlsx file would it be possible to smooth out the data such that nearby peaks merge into a single curve/peak? Would it be possible to do this for a certain window-size of the x-axis i.e. merge all peaks that are within 200 of each other?

    Thank you!

    - Kayleigh
    Attached Files Attached Files

  2. #2
    Forum Guru
    Join Date
    04-13-2005
    Location
    North America
    MS-Off Ver
    2002/XP and 2007
    Posts
    15,829

    Re: Data Smoothing

    I'm sure it would be possible. Can you explain exactly how you want to smooth these data -- exactly what you mean by "merging" the peaks? Do you want some kind of moving average. Some kind of localized curve fitting? Can you show the results you expect in your sample file?

    Once we understand exactly how you want to merge peaks, we can figure out the algorithm to accomplish that.
    Quote Originally Posted by shg
    Mathematics is the native language of the natural world. Just trying to become literate.

  3. #3
    Registered User
    Join Date
    11-19-2013
    Location
    United Kingdom
    MS-Off Ver
    Excel 2011 (Mac)
    Posts
    3

    Re: Data Smoothing

    Localised curve fitting seems an appropriate method but I am not well versed in statistics. It is a little difficult to fully show what I fully mean. The gaussian smoothing here:

    http://www.swharden.com/blog/images/smooth2.png

    Shows what I need partially - where multiple peaks are represented as smoothed curves if they are adjacent/close to each other.

    - Kayleigh
    Last edited by KayleighEpps; 11-19-2013 at 11:49 AM.

  4. #4
    Registered User
    Join Date
    11-19-2013
    Location
    United Kingdom
    MS-Off Ver
    Excel 2011 (Mac)
    Posts
    3

    Re: Data Smoothing

    I also need to be able to define a window size for the smoothing i.e. the peaks at 441 and 444 should form a single curved peak together but it should not include the peak at 414 as it's too far away.

  5. #5
    Forum Guru
    Join Date
    04-13-2005
    Location
    North America
    MS-Off Ver
    2002/XP and 2007
    Posts
    15,829

    Re: Data Smoothing

    I haven't been able to fully wrap my head around Gaussian smoothing/filtering, but it also seems like you aren't fully decided that Gaussian filtering is what you want to use. At this point, I would suggest you decide what smoothing algorithm you want to use. Your sample plot shows Gaussian, Triangle, and Window. I'm also aware of moving average and Loess (local curve fitting using polynomials). There are probably others. I think most data smoothing algorithms will follow this basic skeleton:

    1) Determine window size.
    2) Obtain parameters for smoothing equation for the window specified in 1.
    3) Using these parameters, calculate a smoothed value for y at the desire x.
    4) repeat for the next desired window.

    The big unkown is exactly what to put in step 2, which will depend mostly on what smoothing algorithm you decide you want. You might review this wikipedia article for a discussion of different strategies for data smoothing.
    http://en.wikipedia.org/wiki/Smoothing

  6. #6
    Forum Guru
    Join Date
    04-13-2005
    Location
    North America
    MS-Off Ver
    2002/XP and 2007
    Posts
    15,829

    Re: Data Smoothing

    To illustrate the generic algorithm, here's a sample workbook using a "local polynomial" to smooth the data. I'm sure there are other ways to do it.

    Controlling the desired "window" to be used for the smoothing function is done by changing the references in the linest() function.
    Attached Files Attached Files

+ Reply to Thread

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Data smoothing through averages fails
    By greendaffodil in forum Excel Formulas & Functions
    Replies: 5
    Last Post: 05-10-2013, 08:40 AM
  2. Smoothing Data
    By munleyj in forum Excel Formulas & Functions
    Replies: 17
    Last Post: 02-20-2013, 01:48 AM
  3. Data Smoothing
    By tbarlett in forum Excel Formulas & Functions
    Replies: 1
    Last Post: 01-18-2013, 03:00 PM
  4. Smoothing Data in Coumns
    By munleyj in forum Excel Formulas & Functions
    Replies: 2
    Last Post: 12-26-2012, 04:49 AM
  5. Smoothing data problem
    By dk1isme in forum Excel General
    Replies: 0
    Last Post: 06-12-2008, 10:26 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Search Engine Friendly URLs by vBSEO 3.6.0 RC 1