Difference between local time and "created_at

Hello

The time returned by "created_at" does not correspond to the local time

e.g. 18:54:33.401 -> Message:{"channel_id":2499901, "created_at": "2024-08-21T16:54:31Z"....}

although my profile is correctly filled in, the time indicated on the plot is correct

Should I add the term: ?timezone = Europe%2FParis

if where please I do not have a field in "channel setting" to add it

Thank you in advance.

Answer 1

[Walter Roberson]

"2024-08-21T16:54:31Z"

The Z at the end of the timestamp specifically means "Zulu" time, which is UTC.

It would be expected that times in that format would be converted to be in timezone UTC. To plot them in local time, you would need to change the TimeZone property of the data.

[noone Me]

Thanks Walter but I don't know where to change the topic to read "2024-08-21T16:54:31:+02.00".

Answer 2

[Star Strider]

To illustratte —

TZ = timezones("Europe");
disp(TZ)

             Name              Area     UTCOffset    DSTOffset
    ______________________    ______    _________    _________

    {'Europe/Amsterdam'  }    Europe        1            1    
    {'Europe/Andorra'    }    Europe        1            1    
    {'Europe/Astrakhan'  }    Europe        4            0    
    {'Europe/Athens'     }    Europe        2            1    
    {'Europe/Belgrade'   }    Europe        1            1    
    {'Europe/Berlin'     }    Europe        1            1    
    {'Europe/Bratislava' }    Europe        1            1    
    {'Europe/Brussels'   }    Europe        1            1    
    {'Europe/Bucharest'  }    Europe        2            1    
    {'Europe/Budapest'   }    Europe        1            1    
    {'Europe/Busingen'   }    Europe        1            1    
    {'Europe/Chisinau'   }    Europe        2            1    
    {'Europe/Copenhagen' }    Europe        1            1    
    {'Europe/Dublin'     }    Europe        0            1    
    {'Europe/Gibraltar'  }    Europe        1            1    
    {'Europe/Guernsey'   }    Europe        0            1    
    {'Europe/Helsinki'   }    Europe        2            1    
    {'Europe/Isle_of_Man'}    Europe        0            1    
    {'Europe/Istanbul'   }    Europe        3            0    
    {'Europe/Jersey'     }    Europe        0            1    
    {'Europe/Kaliningrad'}    Europe        2            0    
    {'Europe/Kiev'       }    Europe        2            1    
    {'Europe/Kirov'      }    Europe        3            0    
    {'Europe/Lisbon'     }    Europe        0            1    
    {'Europe/Ljubljana'  }    Europe        1            1    
    {'Europe/London'     }    Europe        0            1    
    {'Europe/Luxembourg' }    Europe        1            1    
    {'Europe/Madrid'     }    Europe        1            1    
    {'Europe/Malta'      }    Europe        1            1    
    {'Europe/Mariehamn'  }    Europe        2            1    
    {'Europe/Minsk'      }    Europe        3            0    
    {'Europe/Monaco'     }    Europe        1            1    
    {'Europe/Moscow'     }    Europe        3            0    
    {'Europe/Oslo'       }    Europe        1            1    
    {'Europe/Paris'      }    Europe        1            1    
    {'Europe/Podgorica'  }    Europe        1            1    
    {'Europe/Prague'     }    Europe        1            1    
    {'Europe/Riga'       }    Europe        2            1    
    {'Europe/Rome'       }    Europe        1            1    
    {'Europe/Samara'     }    Europe        4            0    
    {'Europe/San_Marino' }    Europe        1            1    
    {'Europe/Sarajevo'   }    Europe        1            1    
    {'Europe/Saratov'    }    Europe        4            0    
    {'Europe/Simferopol' }    Europe        3            0    
    {'Europe/Skopje'     }    Europe        1            1    
    {'Europe/Sofia'      }    Europe        2            1    
    {'Europe/Stockholm'  }    Europe        1            1    
    {'Europe/Tallinn'    }    Europe        2            1    
    {'Europe/Tirane'     }    Europe        1            1    
    {'Europe/Ulyanovsk'  }    Europe        4            0    
    {'Europe/Uzhgorod'   }    Europe        2            1    
    {'Europe/Vaduz'      }    Europe        1            1    
    {'Europe/Vatican'    }    Europe        1            1    
    {'Europe/Vienna'     }    Europe        1            1    
    {'Europe/Vilnius'    }    Europe        2            1    
    {'Europe/Volgograd'  }    Europe        3            0    
    {'Europe/Warsaw'     }    Europe        1            1    
    {'Europe/Zagreb'     }    Europe        1            1    
    {'Europe/Zaporozhye' }    Europe        2            1    
    {'Europe/Zurich'     }    Europe        1            1    

MessageTime = datetime("2024-08-21T16:54:31Z", 'InputFormat','yyyy-MM-dd''T''HH:mm:ssZ', 'TimeZone','Europe/Paris')

MessageTime = datetime
   21-Aug-2024 18:54:31

.

[noone Me]

Thanks Star Striderr,

but I don't know where to put this additional information in my channel.

I'm in MQTT via ESP32, the dating of the curves on the trace is correct but the message still sends GMT.

Where should I make the change please?

[Star Strider]

I do not understand what you are doing.

I demonstrated a way to convert the time you have to the time you want. You probably need to keep the Z time in your application.

[noone Me]

RE..

I'm sorry (thanks again for your help) but I don't know where to put the "MessageTime" that you programmed for me. I'm new to ThingSpeack and the topic I've received is as follows:

13:48:15.884 -> Message arrived from the topic: channels/2499901/subscribe

13:48:15.884 -> Message:{"channel_id":2499901,"created_at":"2024-08-22T11:48:14Z","entry_id":34325,"field1":"34.10","field2":"34.40","field3":"69","field4":"27.81","field5":null,"field6":null,"field7":null,"field8":null,"latitude":null,"longitude":null,"elevation":null,"status":null}

Where can I take action to change the "created_at" please ?

[Star Strider]

I have no experience with ThingSpeak.

One option —

dts = extractBetween('{"channel_id":2499901,"created_at":"2024-08-22T11:48:14Z","entry_id":34325,"field1":"34.10","field2":"34.40","field3":"69","field4":"27.81","field5":null,"field6":null,"field7":null,"field8":null,"latitude":null,"longitude":null,"elevation":null,"status":null}', '"created_at":',',')

dts = 1x1 cell array
    {'"2024-08-22T11:48:14Z"'}

MessageTime = datetime(dts{:}, 'InputFormat','"yyyy-MM-dd''T''HH:mm:ssZ"', 'TimeZone','Europe/Paris')

MessageTime = datetime
   22-Aug-2024 13:48:14

I am not certain how to extract that particular information (the Message cell array to use in the extractBetween call) from whatever ThingSpeak returns, however if you can do that, this approach should work.

.