How to plot data from a single day?

Hello everyone! I am currently a novice on the matlab world.

I have a table that goes as such:

"10-Jul-2019 -24.129 -40.848

10-Jul-2019 -24.129 -40.818

10-Jul-2019 -24.132 -40.512

10-Jul-2019 -24.132 -40.393

13-Jul-2019 -24.578 -40.304

14-Jul-2019 -24.675 -41.144

14-Jul-2019 -24.573 -40.959

14-Jul-2019 -24.573 -40.798

14-Jul-2019 -24.573 -40.798

14-Jul-2019 -24.574 -40.679

14-Jul-2019 -24.573 -40.569

14-Jul-2019 -24.574 -40.507

15-Jul-2019 -24.682 -40.93

17-Jul-2019 -24.761 -41.586 "

And I want to plot a different chart for each day.

Does anyone know how to do this?

Thanks!!

Answer 1

[Star Strider]

If ‘T1’ is your table, and y0ou defined it with a datetime array as the first column try this:

G = findgroups(day(T1{:,1}));
DayGroups = accumarray(G, (1:size(G,1))', [], @(x){T1(x,:)});

Then see: Plot Dates and Durations to do the plotting.

Example —

for k = 1:size(DayGroups,1)
    figure(k)
    plot(DayGroups{k}{:,1}, DayGroups{k}{:,2:end}, '-p')
    grid
end

This worked with data that I already have in a similar table that I have already defined. I have no idea what your table actually is, or how you have defined it, so I cannot use the text that you posted.

[Arthur Romeu]

thanks!!

[Star Strider]

As always, my pleasure!

[Arthur Romeu]

I'm so happy it's working!!!

my code goes as follows:

plot_avistagens = table(data_avistagens,lat_avistagens,lon_avistagens)

D = findgroups(datetime(plot_avistagens{:,1}));
DayGroups = accumarray(D, (1:size(D,1))', [], @(x){plot_avistagens(x,:)});

for k = 1:size(DayGroups,1)
    figure(k)
    plot(DayGroups{k}{:,2}, DayGroups{k}{:,3:end}, 'bp')
    grid
end

I changed line 3 to datetime because the code was selecting every day 1 with no month distinction (the full table has 210 lines and more will be added).

And then I changed the plot function to plot XY using the XY coordinates.

So now it's all right! Thanks Star Strider, I learned a lot!

[Star Strider]

As always, my pleasure!

My code was predicated on the time variable already being a datetime object.

Example —

C = {'10-Jul-2019'        -24.132           -40.512       
     '10-Jul-2019'        -24.132           -40.393       
     '13-Jul-2019'        -24.578           -40.304       
     '14-Jul-2019'        -24.675           -41.144       
     '14-Jul-2019'        -24.573           -40.959};

D1 = table(datetime(C(:,1)), 'VariableNames',{'Date'});             % Create ‘datetime’ Table
D2 = cell2table(C(:,2:3));                                          % Table For Other Variables
T1 = [D1,D2];                                                       % Concatenate To Create ‘T1’

G = findgroups(day(T1{:,1}));
DayGroups = accumarray(G, (1:size(G,1))', [], @(x){T1(x,:)});

I was initially not certain how you had imported or defined the first column, so I was hesitant to provide specific code to create the table.

[Arthur Romeu]

I am really struggling to make the images right :(

Your code is awesome and I never thought I could group my data on this manner. I didn't know I could keep asking here so that's why I created the other topic.

I'm having a hard time figuring out how to make the charts plot the way I want to. Right now I have this piece of code:

D = findgroups(datetime(plot_avistagens{:,1}));
DayGroups = accumarray(D, (1:size(D,1))', [], @(x){plot_avistagens(x,:)});

Dt = findgroups(datetime(plot_tracking{:,1}));
DayGroups_t = accumarray(Dt, (1:size(Dt,1))', [], @(x){plot_tracking(x,:)});


for k = 1:size(DayGroups_t,1)

    figure(k)
    plot(DayGroups{k}{:,2}, DayGroups{k}{:,3:end}, 'bp', DayGroups_t {k}{:,2}, DayGroups_t{k}{:,3:end}, 'r:')
    grid
    
end

Both cell groups "DayGroups" and "DayGroups_t" have the same structure (datetime,Xcoordinates,Ycoordinates). However, what I need is to plot the events that happened on the same day from both cell groups. Right now what the code is doing is plotting the first day of DayGroups with the first day of DayGroups_t, but they are not the same day. I will include the theory behing what I'm trying to do and both DayGroups.mat and DayGroups_t.mat for better understanding.

"During an oceanographic expedition, the ship recorded its position on an hourly basis (data_tracking, lat_tracking and lon_tracking). During those days of expedition, marine mammals (whales and dolphins) were registered on another table (data_avistagens, lat_avistagens, lon_avistagens). To quickly confirm that the coordinates of the "encounters" are correct (if it's too far from the tracking data there is no way someone could've seen the animal) I am trying to display the tracking data from a given day along with the whale watching data from that day.

In other words, I'm trying to visually identify if all of the whales and dolphins have infact the right coordinates by plotting the events of the day along with the tracking of the day on an X Y chart."

This is the full code:

%% Preallocate Memory
lat_avistagens = [];
lon_avistagens = [];
ano_avistagens = [];
mes_avistagens = [];
dia_avistagens = [];
data_avistagens = [];
plot_avistagens = [];

D = [];
Dt = [];
DayGroups = [];
DayGroups_t = [];

lat_tracking = [];
lon_tracking = [];
ano_tracking = [];
mes_tracking = [];
dia_tracking = [];
data_tracking = [];
plot_tracking = [];

quit = [];
data_tracking_tratado = [];
lat_tracking_tratado = [];
lon_tracking_tratado = [];

%% Parte 1: avistagens
% Caminho para o RGA
path_ = 'c:\Users\ivan_\Desktop\tmp_arthur\matlabb\table1.xlsx';
    %% Trabalhando com a matriz
    ImportOptions_ = detectImportOptions(path_, 'NumHeaderLines', 1, 'Sheet', 3);
        aux1 = readtable(path_,ImportOptions_);

    lat = table2array(aux1(:,5));
    lon = table2array(aux1(:,6));
    ano = table2array(aux1(:,2));
    mes = table2array(aux1(:,3));
    dia = table2array(aux1(:,4));

    lat_avistagens=[lat_avistagens;lat];
    lon_avistagens=[lon_avistagens;lon];
    ano_avistagens=[ano_avistagens;ano];
    mes_avistagens=[mes_avistagens;mes];
    dia_avistagens=[dia_avistagens;dia];

    err = 'Latitude apresenta inconformidade.';
    erro = 'Longitude apresenta inconformidade.';
    if lat_avistagens < -30 %esses valores são arbitrários
        error(err);
    end
    if lon_avistagens < -45 %esses valores são arbitrários
        error(erro);
    end

    %save dados_avistagens.mat

    clearvars lat lon ano mes dia aux1 ImportOptions_ path_

    %% Organizando datas
    data_avistagens = datetime(ano_avistagens,mes_avistagens,dia_avistagens,'TimeZone','America/Sao_Paulo');
    %data_avistagens.TimeZone = 'America/Sao_Paulo'; nesse caso não precisa
    %disso porque as datas originais já estão no horário de Brasília.

%% Parte 2: tracking
% Caminho para a planilha de Tracking
path_ = 'c:\Users\ivan_\Desktop\tmp_arthur\matlabb\table2.xlsx';
    %% Trabalhando com a matriz
    
    % Necessario laco para ler varias abas (sheets) - repeticao de acoes
%for cgg = 1:36

    ImportOptions_ = detectImportOptions(path_, 'NumHeaderLines', 6);
        aux1 = readtable(path_,ImportOptions_);

    lat = table2array(aux1(:,10));
    lon = table2array(aux1(:,9));
    ano = table2array(aux1(:,2));
    mes = table2array(aux1(:,3));
    dia = table2array(aux1(:,4));

    lat_tracking=[lat_tracking;lat];
    lon_tracking=[lon_tracking;lon];
    ano_tracking=[ano_tracking;ano];
    mes_tracking=[mes_tracking;mes];
    dia_tracking=[dia_tracking;dia];

clearvars lat lon ano mes dia aux1 ImportOptions_ path_
    %% Organizando datas
    data_tracking = datetime(ano_tracking,mes_tracking,dia_tracking,'TimeZone','UTC');
    data_tracking.TimeZone = 'America/Sao_Paulo';
    
    %% Reduzindo a resolucao temporal: quit = nº de celulas a pular

    quit = 59 ; 
    data_tracking_tratado = data_tracking(1:quit:end) ;
    lat_tracking_tratado = lat_tracking(1:quit:end) ;
    lon_tracking_tratado = lon_tracking(1:quit:end) ;

%% Plotagem dos gráficos
plot_avistagens = table(data_avistagens,lat_avistagens,lon_avistagens);
plot_tracking = table(data_tracking_tratado,lat_tracking_tratado,lon_tracking_tratado);

D = findgroups(datetime(plot_avistagens{:,1}));
DayGroups = accumarray(D, (1:size(D,1))', [], @(x){plot_avistagens(x,:)});

Dt = findgroups(datetime(plot_tracking{:,1}));
DayGroups_t = accumarray(Dt, (1:size(Dt,1))', [], @(x){plot_tracking(x,:)});


for k = 1:size(DayGroups_t,1)

    figure(k)
    plot(DayGroups{k}{:,2}, DayGroups{k}{:,3:end}, 'bp', DayGroups_t {k}{:,2}, DayGroups_t{k}{:,3:end}, 'r:')
    grid
    
end

I really need some help :,( I tried using functions find() and datefind() but I can't make this work

sorry to keep bothering with this

[Arthur Romeu]

Hi! is this a good way to think?

for k = 1:size(DayGroups_t,1)
    j = 1:size(DayGroups,1);
    if DayGroups_t{j}{1,1} == DayGroups{k}{1,1}
        figure(k)
        plot(DayGroups{k}{:,2}, DayGroups{k}{:,3:end}, 'bp', DayGroups_t {k}{:,2}, DayGroups_t{k}{:,3:end}, 'r:')      
        grid
    else
        j = j+1
    end
end

It says that "Index exceeds matrix dimensions." What am I doing wrong?