# How to plot timeseries graph

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emily bristow on 30 Nov 2020
Answered: Mathieu NOE on 8 Dec 2020
I have 7 months of dissolved oxygen data through a water column (March, April, May, June, July, August, November) I need to plot this as a timeseries but I'm unsure on where to start.
How do I plot the bottom water oxygen concnetrations against each month they were taken?
The excel file attatched is one example of the data.

#### 1 Comment

Mathieu NOE on 8 Dec 2020
hello
how are the data sampled ? I assume the attached xlsx file does not cover the entire 7 monthes ?
you want to plot each seperate month (one plot = one month ? )

Mathieu NOE on 8 Dec 2020
hello again
% data format (7 columns)
% depth temp salin sig chl DO DO%
% -5 9,491 35,311 27,281 0,59 285,5 100,31
% assuming one data = one day
% how many days in each month :
% March : 31 , April : 30 , May : 31 , June : 30 , July : 31, August : 31 , November : 30
monthes = {'March','April','May','June','July','August','November'};
days_per_month = [31 30 31 30 31 31 30];
filename = "mar2014ctd2.xlsx"; % extended data length to cover the 7 month / 1 data per day range
[m,n] = size(C);
data = cell2mat(C(2:m,:)); % start at row index 2 to ignore header line
stop_index = 1; % init
%% plot
for ci = 1: length(days_per_month)
start_index = stop_index;
stop_index = start_index-1 + days_per_month(ci);
x_axis = 1:1:days_per_month(ci);
DO_extract = data(start_index:stop_index,6); % 6th column = DO
figure(ci), plot(x_axis,DO_extract,'*-');grid
title(monthes(ci));
xlabel('Days');
ylabel('DO');
end