Timezone handling

[eddiemuc]

c:geo deals a lot with both time data and location data. When the users currentl location is in another timezone than a located item (eg a Geocache) then handling and displaying times and dates becomes tricky. And let's not forget about summer/wintertime either :-) Examples: events /event time in another timezone.

A proposed solution could be:

• store and handle all timestamp information uniquely (e.g. Unix time in database and in objects, UTC in XML, json and the like)
• when timestamps should be displayed, then convert them on the fly using location and current time as context
• the former requires a decision on what to display in such context (eg should we display local event times or event times in the users current locationsTimezone or users Timezone set on the phone? Or all three of them if the differ? :-))

To do this I guess we would need a lib to get us the timezone for a given location. A quick search revealed two candidates:

• Timeshape - Java library
• TimeZoneMap- Java and Android library

Opinions?

[eddiemuc]

An imaginary example (such examples help me think :-)): Assume you are in portuguese (GMT-1), your phone is set to german timezone (GMT+1) and you look at an event in New York (GMT-5), taking place at new york local time 4pm-5pm

--> we would have four different times we could display

• GMT
• German time
• portuguese time
• new york time

--> which of those times should be displayed?

[ztNFny]

Timezone of a event is available in API - but not in web.

See https://github.com/cgeo/cgeo/issues/13515#issuecomment-1280001202

[Lineflyer]

--> which of those times should be displayed?

I hate timezone issue.

But in your example it would be: The GUI should show the time of the event using the timezone the device is currently using. In your example its in the responsibility of the user to set his device to the timezone he is currently in.

Alternatively we could skip time zoning in general, take the event time as it is and add something like "(local time at event location)". If there is no time zone info on the web page, this seems to be the only option without guessing or applying complex procedures (like getting the timezone from the coordinates).

[ztNFny]

IF timezone becomes available then imho we should display:

• Local Event time (as primary info)
• Event time according to users current timezone (and store UTC internally I guess)