Try calling sgolayfilt() to smooth the data, if that's what you want to do.
% Initialization Steps.
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 18;
set(gcf,'color','w')
%%
filehtm = dir('moving_windown_test.xlsx') ;
for ii = 1 : length(filehtm);
filehtm(ii).name
[num,str,xlsdata] = xlsread(filehtm(ii).name) ; %num數值 str字串
end
time = num(:,1) ;
tide_detrend = num(:,2) ./ 1000 ;
tide = tide_detrend ;
tide_outline = tide_detrend;
%% set time
YYYY = fix(time/1000000) ;
MM = mod(fix(time/10000),100) ;
DD = mod(fix(time/100),100) ;
HH = mod(time,100) ;
tt = datenum(YYYY,MM,DD,HH,0,0) ;
%%
kkk= 0;
%% 設定時間序列
for yyy = 1961 :1: 1965
t1 = datenum(yyy,1,1) : 1/24 : datenum(yyy+1,1,1) ; % 不能使用t1(yyy)
t1(end)=[];
%% step 1 - Q1 ..... 先篩選離群值
kkk = kkk + 1 ;
Q1(kkk) = prctile(tide_outline, 25)
Q3(kkk) = prctile(tide_outline, 75)
IQR(kkk) = Q3(kkk) - Q1(kkk) ;
upperLimit(kkk) = Q3(kkk) + 1.5*IQR(kkk);
lowerLimit(kkk) = Q1(kkk) - 1.5*IQR(kkk) ;
tide_outline(tide_outline > upperLimit | tide_outline<lowerLimit) = nan ;
%% step 2 - 將空白日期補上nan
for j = 1 : length(t1); % 建立兩個tide變數 與篩選前後做比較
if (isempty(find(tt==t1(j))))
r_tide(j) = nan ;
else
r_tide(j) = tide(find(tt==t1(j))) ;
end
end
for j = 1 : length(t1);
if (isempty(find(tt==t1(j))));
r_tide_removeoutline(j) = nan ;
% kkk = kkk + 1
else
r_tide_removeoutline(j) = tide_outline(find(tt==t1(j))) ;
end
end
for i = 1 : length(t1) ; % 補上完整日期(調和用)
field_day(i) = (yyy+(i - 1) * 60 * 60 / 86400/365) ;
end
% Remove nan's
nanIndexes = isnan(r_tide);
field_day(nanIndexes) = [];
r_tide(nanIndexes) = [];
% Plot good data only.
plot(field_day,r_tide);hold on
plot([yyy,yyy+1],[upperLimit(kkk),upperLimit(kkk)],'--.k','DisplayName','upper');
plot([yyy,yyy+1],[lowerLimit(end),lowerLimit(end)],'--.k','DisplayName','upper');
grid on;
% Smooth the data with a Savitzky-Golay filter.
windowWidth = 1001; % Some large odd number.
smoothTide = sgolayfilt(r_tide, 2, 1001); % Requires Signal Processing Toolbox.
% smoothTide = movmean(r_tide, windowWidth); % Requires no toolbox.
plot(field_day, smoothTide, 'r-', 'LineWidth', 5);
if yyy < 1965
promptMessage = sprintf('Showing year %d\nDo you want to Continue processing,\nor Quit processing?', yyy);
titleBarCaption = 'Continue?';
buttonText = questdlg(promptMessage, titleBarCaption, 'Continue', 'Quit', 'Continue');
if contains(buttonText, 'Quit', 'IgnoreCase', true)
return; % or break or continue.
end
end
end
