Re: Problem plotting time on X axis

[Fritz Sonnichsen]

Thanks Ian! This solved the problem. I guess the main point was that I need to remove the whole number offset from the serial date.
Fritz

On 2/15/2018 8:46 AM, Ian McCallion wrote:

Hi Fritz,

I think this is what you want:

  dtmeT = {"9:00:38" "9:00:39" "9:00:40" "9:00:41"}
  T = [   23.900    23.900   22.900   21.100]

  timeFormat='HH:MM:SS';

  ser_date=(rem(datenum(dtmeT,timeFormat),1));

  plot(ser_date,T ,'color','k'  );

  datetick('x',13,'keepticks');
  axis([-Inf Inf 20 75]);

Cheers... Ian

On 14 Feb 2018 9:37 pm, "Fritz Sonnichsen" <address@hidden> wrote:

Thanks Ian.
The seem to be in proper sequence. I am not asking you to do my work but to see this it may be easiest to just run this code below:

1;
clear all
fflush(stdin);
filenameT='C:\Users\fsonnichsen\Dropbox\CHANOS\LEDs\data\2018_02_14a\T.txt';
[dtmeT, T] = textread (filenameT, "%s %f");

%%%%%%%%%%  TEMPERATURE PLOT %%%%%%%%%%%%%%%
  timeFormat='HH:MM:SS';
  ser_date=datenum(dtmeT,timeFormat); %serial date is secs since 1/1/0000
  plot(ser_date,T ,'color','k'  );
%  plot(ser_date-datenum("00:00:00"),T ,'color','k' )
  datetick('x',timeFormat,'keepticks')
    xlen = length(dtmeT);
  axis([0 xlen 20 75])

return
==============DATA ="">==
14:30:06    22.8
14:30:07    22.8
14:30:08    22.8
14:30:09    22.8
14:30:10    22.8
14:30:11    22.7
===============================================

On 2/14/2018 4:03 PM, Ian McCallion wrote:

Are you sure all the dates are valid and in a sensible range?

On 14 Feb 2018 7:01 pm, "Fritz Sonnichsen" <address@hidden> wrote:

Octave 4.0.0
I am trying to plot a time series data. I found some examples and tried them but they don't seem to work. I have data as shown:
9:00:38      23.9
9:00:39      23.9
.....

My code looks like this:
[dtmeT, T] = textread (filenameT, "%s %f");  %read in the data
   timeFormat='HH:MM:SS';
  ser_date=datenum(dtmeT,timeFormat); %serial date is secs since 1/1/0000
  plot(ser_date,T ,'color','k'  );
  datetick('x',timeFormat,'keepticks')
  xlen = length(dtmeT)  ;
  axis([0 xlen 20 35])

I get a time labeled axis as expected, but I do not see the plot of T.  The data is valid-if I plot it without time formatting it works fine.

thanks
fritz



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