Moving window of 100 points with 20 points overlap.

Hi everybody

I have around 500 points. My x axis-times, y-magnitudes. I need to do plot moving window of 100 points averages with 20 point overlap over time. How I may do the plot? I attached something sample plot also. (Please see my code and excel file, I need to continue my this code ...

[NUMERIC,TXT,RAW]=XLSREAD('sihex.xlsx');
A= -0.59;
B = 43.45;
C=0.09;
x=NUMERIC(:,2);
y=NUMERIC(:,1);
Mag=NUMERIC(:,3);
for iii=1:length(TXT);
  date_str(iii,:)=TXT(iii,1);
end
date_num=datenum(date_str,'dd/mm/yyyy');
condition11=(Mag >= 0.8 &  x > A-C & x < A+C & y > B-C & y < B+C);
plot(date_num(condition11),Mag(condition11),'.b');
datetick('x','yyyy','keeplimits'))

Answer 1

[dpb]

Nfilt=20;
b=ones(1,Nfilt)/Nfilt;              % weights
magFiltered=[nan filter(b,1,mag)];  % weight average (includes end effects)
magFiltered(2:nFilt-1)=nan;         % replace end effects w/ NaN keeping time location

[davit petraasya]

Dear dpb, thanks for your response! Could you tell me is it for 100 points with 20 points overlap? Also how I can get the plot? I am not getting plot yet.

[dpb]

I've no klew what the "100 events" means, the above is a moving average of nPoints.

Oh, rereading I missed part of the request...no, the above doesn't do the "jump", it's a step increment of unity. As IA says, use either blockproc or conv instead.

[davit petraasya]

Sorry dpb for my a little bit confusion text. Actually events means points. 100 events=100 points. Thanks.

Answer 2

[Image Analyst]

An alternate way is to use blockproc(), if you have the Image Processing Toolbox. It gives you control over the window size and the "jump" length.

Or, you could use conv() (which moves over one element at a time) and then just subsample every 20th element from the result.

[davit petraasya]

Thanks for the comment Image Analyst. I will try to use blockproc function.

[Image Analyst]

I've attached two demos where I use the function in a wide variety of ways. Adapt as needed. Good luck.