Setting XTicks with Datetime reuslt in an error

Hi Together

normaly I can solve all my issues with a search here, but for this problem i didn't found any workins solution:

I have Data, which correlates with a date.

now I want to set the x axis correlating to the data, but anything i try, result in the same error:

this one does not work:

xtickformat('yyyy-MM-dd')

xticks(datetime(conf_t(day_sel):hours(2):datetime(conf_t(day_sel))+hours(24)))

another try:

ticlocs = datetime(conf_t(day_sel):hours(2):datetime(conf_t(day_sel))+hours(24)); %datetime(DateString); %R2014b or later

ticlocs.Format = 'dd-MMM-yyyy';

set(gca, 'XTick', ticlocs);

axes('XTick', datetime(conf_t(day_sel):hours(2):datetime(conf_t(day_sel))+hours(24)) , 'XTickLabelMode', 'manual')

Error using set

Value must be a vector of type single or double whose values increase.

axes('XTick', datetime(conf_t(day_sel):hours(2):datetime(conf_t(day_sel))+hours(24)) , 'XTickLabelMode', 'manual')

Error using axes

Value must be a vector of type single or double whose values increase.

direct trial:

xticks(datetime(conf_t(day_sel):hours(2):datetime(conf_t(day_sel))+hours(24)))

Error using xticks

Tick values must be a vector of increasing numeric values.

BUT: my date has increasing Values:

datetime(conf_t(day_sel)):hours(2):datetime(conf_t(day_sel))+hours(24))

ans =

1×13 datetime array

Columns 1 through 7

31-Jul-2022 14:00:00 31-Jul-2022 16:00:00 31-Jul-2022 18:00:00 31-Jul-2022 20:00:00 31-Jul-2022 22:00:00 01-Aug-2022 00:00:00 01-Aug-2022 02:00:00

Columns 8 through 13

01-Aug-2022 04:00:00 01-Aug-2022 06:00:00 01-Aug-2022 08:00:00 01-Aug-2022 10:00:00 01-Aug-2022 12:00:00 01-Aug-2022 14:00:00

so

how can I create an Axis with an 2h interval with my required date?

thanks in advance!!

Answer 1

[Wolfram Murr]

Hi Karim,

thanks for your reply, unfortunatelly i do generate the dates over several days:

conf_t = {'27-Jul-2022 14:00:00';'28-Jul-2022 14:00:00';'29-Jul-2022 14:00:00';'30-Jul-2022 14:00:00';'31-Jul-2022 14:00:00'};%

Seq2 = [2 2 4 6 8 10 12 14 16 18 20 4; 2 2 2 2 2 2 2 2 2 2 2 2]; %Sequenz 2 mit den verschiedenen Flüssen + Zeiten in h
start_utc = ((datenum(conf_t) - datenum('01-Jan-1970'))*86400)-7200;

S_utc(:,1) = start_utc(:); % startwert
for k = 1:length(S_utc(:,1))
    for i = 1:length(Seq2(1,:)+1)% Utc zeiten gem S1/S2 erzeugen
        S_utc(k,i+1) = S_utc(k,i)+Seq2(2,i)*3600; 
    end
end % Utc Zeiten erzeugen

which makes it not practicable to write this manualy

BUT

your reply brought me to an Idea, an research and the solution

the different kind of brackets/ Type of Data was the problem.

here is the Solution (which works)

xticks(reshape(datetime(conf_t(day_sel):hours(2):datetime(conf_t(day_sel))+hours(24)), 1, []))

(just add the "reshape" function)

Answer 2

[Karim]

you can use datetimes directly as ticks. To make sure that all ticks are shown you can use the xticks command, and for readability i would recommend to rotate them a bit using xtickangle

MyTimes = ["31-Jul-2022 14:00:00";    "31-Jul-2022 16:00:00";    "31-Jul-2022 18:00:00";    "31-Jul-2022 20:00:00";    "31-Jul-2022 22:00:00";    "01-Aug-2022 00:00:00";    "01-Aug-2022 02:00:00";    "01-Aug-2022 04:00:00";    "01-Aug-2022 06:00:00";    "01-Aug-2022 08:00:00";    "01-Aug-2022 10:00:00";    "01-Aug-2022 12:00:00";    "01-Aug-2022 14:00:00"];
MyTimes = datetime(MyTimes);

figure
stem(MyTimes,rand(1,numel(MyTimes)))
xticks(MyTimes) % add this step to make sure that all ticks are shown
xtickangle(45) % add this to rotate the ticks for sake of readability