Beginners Question - diagram date / values

[Martin Wagner]

Hi @all,

I'm trying to create a simple time / values X-Y diagram. However, I'm
having a weird resolution problem on the X axis. 
For some reason, multiple y values are assinged to one sinlge X time
value (see https://ibb.co/eZJYxn).
This is the same data in libre office: https://ibb.co/iLYcOS .

When I check the time values, all of them are the same values.

Any ideas what I'm doing wrong?

Thanks for your help!



This is the csv source data:

Time,Temperature
27.02.2018 17:10:56,19.99
27.02.2018 17:11:57,19.91
27.02.2018 17:12:58,20.01
27.02.2018 17:13:59,19.98
27.02.2018 17:15:00,20.15
27.02.2018 17:16:01,20.20
27.02.2018 17:17:02,20.14
... many more days

and this is the code I tried:

fd = fopen('file.csv')

a = textscan(fd, '%s %f', 'Delimiter', ',', 'HeaderLines', 1)

a
a = 
{
  [1,1] = 
  {
    [1,1] = 27.02.2018 17:10:56
    [2,1] = 27.02.2018 17:11:57
    [3,1] = 27.02.2018 17:12:58
    [4,1] = 27.02.2018 17:13:59
    [5,1] = 27.02.2018 17:15:00
    [6,1] = 27.02.2018 17:16:01
    [7,1] = 27.02.2018 17:17:02
  }
  [1,2] =

     19.990
     19.910
     20.010
     19.980
     20.150
     20.200
     20.140

}

a{1} = datenum(a{1},'dd.mm.yyyy HH:MM:SS');
a
a = 
{
  [1,1] =

     7.3712e+05
     7.3712e+05
     7.3712e+05
     7.3712e+05
     7.3712e+05
     7.3712e+05
     7.3712e+05

  [1,2] =

     19.990
     19.910
     20.010
     19.980
     20.150
     20.200
     20.140

}

plot(a{1},a{2})