Hello, All. Thank you in advance for any help, contribution and your time. I have been asked to do a contour plot with a data vs time (date and month), the data is like ID.ST

Hello, All. Thank you in advance for any help, contribution and your time. I have been asked to do a contour plot with a data vs time (date and month), the data is like

ID.STN

LON

LAT

START.DATE/

Abala

39.76

13.34

27-Jul

Abobo

34.31

7.53

13-Jul

Abomsa

39.837

8.479

25-May

AddisAbabaBole

38.79871

8.981081

18-May

AddisAbabaObs

38.7475

9.01891

17-May

Adele

39.90292

7.7505

24-May

Adet

37.49312

11.2745

21-May

[Aquatris]

The formatting of the question makes it hard to read.

Also, what type of plot are you looking for? what is your X axis what is your Y axis and what do you want to see in the Z axis(contour lines)?

[Bekalu Tamene]

I want to plot contours for x (longitude), y (latitude), and z (dates such as 27-May).

Answer 1

[Voss]

Maybe something like this would work:

% read the file into a cell array
C = readcell('data.txt');
% make that cell array into a nice table
C = reshape(C,4,[]).';
T = cell2table(C(2:end,:),'VariableNames',strrep(C(1,:),'/',''));
T.('START.DATE') = datetime(T.('START.DATE'),'InputFormat','dd-MMM','Format','preserveinput')

T = 7x4 table
          ID.STN           LON       LAT      START.DATE
    __________________    ______    ______    __________

    {'Abala'         }     39.76     13.34      27-Jul  
    {'Abobo'         }     34.31      7.53      13-Jul  
    {'Abomsa'        }    39.837     8.479      25-May  
    {'AddisAbabaBole'}    38.799    8.9811      18-May  
    {'AddisAbabaObs' }    38.748    9.0189      17-May  
    {'Adele'         }    39.903    7.7505      24-May  
    {'Adet'          }    37.493    11.274      21-May  

% create a figure for plotting
figure

% plot the lon/lat data
plot(T.LON,T.LAT,'.k')
hold on

% make a scatteredInterpolant for constructing the contour
t_min = min(T.('START.DATE'));
z = days(T.('START.DATE')-t_min); % use number of days since t_min in contour Z
SI = scatteredInterpolant(T.LON,T.LAT,z);

% define the grid over which contour Z is calculated
x_min = min(T.LON);
x_max = max(T.LON);
y_min = min(T.LAT);
y_max = max(T.LAT);
X = linspace(x_min,x_max);
Y = linspace(y_min,y_max);
[X,Y] = meshgrid(X,Y);

% calculate contour Z
Z = SI(X,Y);

% plot the contour
contour(X,Y,Z)

% make a colorbar
cb = colorbar();

% make colorbar tick labels dates instead of days since t_min
cb.TickLabels = string(t_min+days(cb.Ticks));

% create text labels for the data points
t = text(T.LON,T.LAT,T.('ID.STN'),'HorizontalAlignment','left','VerticalAlignment','bottom');

% change the alignment of those texts that are off the plot
ext = get(t,{'Extent'});
ext = vertcat(ext{:});
set(t(ext(:,1)+ext(:,3) > x_max),'HorizontalAlignment','right')
set(t(ext(:,2)+ext(:,3) > y_max),'VerticalAlignment','top')

% "manually" make AddisAbabaBole top-aligned
t(4).VerticalAlignment = 'top';

% set axes x and y labels
c = char(176);
xlabel(['LON (' c 'E)'])
ylabel(['LAT (' c 'N)'])

% set colorbar label
ylabel(cb,'START.DATE')

I imagine the actual file has many more locations, in which case you'll probably not want to create text labels for all of them.