MATLAB: Calculating daily Average if only, the value is not zero

dailyaverage

Hello,

I have a dataset, which I have been working on past few weeks.It has solar radiation hourly values(one column of 8760 values) and timestamp data (1 column of 8760 hourly values). I need to calculate the daily average of the solar radiation, which I was able to do using the reshape function.

However, that also took into account the solar radiation value "0 W/m2" during the night hours. I thus need to make a daily average for only solar hours.So looking at combining a for loop, with 'if' and finding averages. But I need help as I am a new coder. Thank you

Best Answer

If you already have an algorithm that compute the mean, the simplest thing would be to replace the 0 with NaN and add the 'omitnan' flag to your call to mean. Mathematically it also makes more sense to ignore nans when calculating mean rather than ignoring 0. So:

solarradiation(solarradiation == 0) = nan;
%...

%in your code calculating mean
something = mean(somesolarradiation, 'omitnan');
%...

Related Solutions

MATLAB: Replacing nan values with the mean of a moving window

Here's a fairly straightforward easy to understand vectorized way of doing it:

% Reshape into 40 days (rows) by 24 columns (hours).
dailyData = reshape(data1, [40,24]);
% Get a map of where the NaNs are
nanMap = isnan(dailyData)
% Count the number of valid, non-nan values per day.
validValuesPerDay = sum(~nanMap, 2)
% Need to sum rows but can't sum with NaNs or result is a NaN,
% so replace NaNs with zeros so we can sum the row.
nonNanData = dailyData;
nonNanData(nanMap) = 0;
sumPerDay = sum(nonNanData, 2) % Sum across the row.
% Get a matrix where each row is the mean of that row.
dailyMeans = sumPerDay ./ validValuesPerDay;
% Expand it to 24 columns.
dailyMeans = repmat(dailyMeans, [1 24]);
% Replace NaNs with the mean
repairedData = dailyData; % Initialize.
repairedData(nanMap) = dailyMeans(nanMap)

MATLAB: How to import average of monthly data from excel file

hello

this is a simple code that will extract monthly data and look for solar radiation above 200

each month data will then be stored in a separate sheet in a excel file (so 12 sheets total)

[data, text, alldata] = xlsread('solar.xlsx');
% Year	Month	Day	Hour	solar_radiation
% i want to import average solar radiation of each month from given excel file 
% but the  average of those data which is greather than 200 and same for weeks .
% % ind of data that exceed 200 in solar_radiation 
% ind = find(ndata(:,5) > 200)
[m,n] = size(data);
month = (min(data(:,2)):max(data(:,2)));
filename_out = 'test.xlsx';
% data selection 
for ci = 1:length(month)
    ind = find(data(:,2) == month(ci))
    data_one_month = data(ind,:);
    % ind of data that exceed 200 in solar_radiation 
    ind = find(data_one_month(:,5) > 200)
    data_selected = data_one_month(ind,:);
    [mm,nn] = size(data_selected);
    % export to excel
    OUT(1,1:n) = text; % paramters in firts line
    OUT(2:mm+1,1:n) = num2cell(data_selected);        % averaged data in second line
    writecell(OUT,filename_out,"Sheet" ,ci); % save OUT to excel file
end

Best Answer

Related Solutions

MATLAB: Replacing nan values with the mean of a moving window

MATLAB: How to import average of monthly data from excel file

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