Time Zones in Reports and Graphs

Its timely to look at the use of time zones in reports and graphs since we will shortly be releasing a version of Smap that includes trend analysis.  This will allow you to create graphs and maps  showing trends in data against time.

The most common date columns in Smap reports are the start and end of the survey.  When these are shown in a table on the Smap server the time zone is included. For example the following is from a survey that started at 7:10pm in a time zone GMT + 11.

  • 2012-03-13 19:10:27.412+11

Note the time zone is shown as +11. When the survey is exported to Excel the time zone information is removed and the time is shown as GMT.

  • 13/03/2012  8:10:27 AM

This is because Excel can’t include the time zone in a date cell.  (At least I don’t think it can). However you can modify the time back to local time.  Dates in Excel are stored as floating point numbers.  If you add “1” to this date it will increment by 1 day.  So to change the time to a time zone of GMT + 11 you can add 11/24.

In a future release of Smap I will add an extra column for the time zone of the survey so that this information is available in the report.

Now getting back to the trend analysis. The times in the x-axis of trend graphs will be shown in the local time of the survey without timezone information.  So for the example above where the time interval is set to show results by the hour.  That survey result will fall within the x-axis period of:

  • 2012-03-13 19

In summary all dates and times in reports are in local time except when exported to Excel when they are shown as GMT.

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