Date shown in 'Time selector' is shifted one day

[iamsaswata]

The date shown on the date time selection panel is shifted one day behind.

For the given example (screenshot), we can see date selected is shown as 29/12/2022. But very surprisingly, the date fetched from geoserver is 30/12/2022. I can also confirm actually it is map of 30/12/2022. Configuration is also shown in the given screenshot.

Any help fixing this is highly appreciated.

[nf-s]

Hi @iamsaswata

The dates in Terria will be in your local timezone. Can you please confirm what timezone your in?

Thanks,
Nick

[iamsaswata]

Hi @nf-s
Thanks for looking into this.

My timezone is Pacific Daylight Time (GMT-7) zone.

[nf-s]

Hi @iamsaswata

The times provided by your GeoServer are most likely in UTC, but Terria will render dates in your local timezone - this is the default behaviour for handling dates in web browsers. This is why you are seeing a different date between the date/time selector - and the time value sent to your GeoServer.

If you want to display UTC times in the Terria UI - you can use the dateFormat configuration option.

For example - if you put UTC: before your format string, then the date will be shown in UTC instead of your local timezone

"dateFormat": "UTC:dd/mm/yyyy"

Let me know how you go!

Thanks 🙂

[JonDHo]

This is an issue for all timezones which are behind UTC (and therefore all of the Americas). The solution identified above (using "dateFormat": "UTC:dd/mm/yyyy") will work to force the UI to show the correct date as it forces the UI to format the date to UTC.

However, this is still an issue if you enable the WMS time filter tool by setting timeFilterPropertyName. In the background, the date list for the time filter is converted to non-UTC dates (and therefore are 1 day behind). The data coming from the WMS service has the correct dates, but Terria adjusts the list automatically.

[nf-s]

Hi @JonDHo are you able to share your Terria JSON configuration with us? Then we can recreate the problem from our side.
Generally speaking, Terria doesn’t do any processing on dates coming from WMS - so I’m not sure how these values could be incorrect.
As for presenting dates in the UI, web browsers will show dates in their local timezone by default. Using the dateFormat parameter can force the UI to show dates in UTC.
The dates you see in the UI are not the dates sent to WMS - we will only send back date strings that are specified in GetCapabilities (or GetFeatureInfo in the case of timeFilterPropertyName)

[JonDHo]

Following on from the discussion on Slack, I believe that my issue is with datacube-ows, not Terria, but will link back here if anything is needed on this end.

[nf-s]

I am going to convert this into a GitHub discussion - we can create more issues as needed if we come across anything