World Time Forecast

We imagine a slide rule useful for scheduling and awaiting events where offsets that change with seasons and prefered times of participants are taken into account.

Example: We schedule an online event at 10am every Wednesday Portland time. Since US and UK enter and leave daylight savings time on different dates it become difficult to predict when to attend the event from London during the spring and fall.

# Output

A slide rule style calculator shows locations on scales and times as vertical cursors. site

We imagine this to be like a map with markers where map scale is chosen to include multiple markers and the viewer can scroll and zoom to see some markers in more detail.

We imagine that like our Map plugin the markers from multiple forecasts can be assembled onto one larger schedule and scaled accordingly. See About Map Plugin

Unlike with maps we desire to consider events from the perspective of multiple locations at once. We imagine thin horizontal scales, one for each location of interest, stacked one upon another upon which events will be marked. Time runs smoothly left to right, locations stack discreetly top to bottom.

The web site Every Time Zone uses the slide rule format to display a single time everywhere.

The SVG graphic primitives easily provide enough rendering and animation primitives for a compelling interaction. A dozen or so helper functions would probably be sufficient as it has been before. github

# Input

An event would be specified with a start time and duration on a date in a place. An event could carry labeling and hyperlinking properties.

A timezone and daylight savings aware calculator would convert from the specified time to a universal time and then to a display time for each band.

Items that could construct and return well specified events would identify themselves as 'event-source'.

Possible markup would include text mixed with keyword lines of specification.

Wiki User/Developer Video Chat Google Hangout DATE Wednesdays TIME 10 am FOR 60 minutes IN Portland ALSO Denver ALSO London

A user in an unanticipated location could configure a forcaster for that location and flow remotely specified events across a lineup and into their own prefered timezone with shorthand markup for known locations.

World Cup Viewing Schedule THERE HERE

Our approach differs from calendar programs in that the sources of information (pages) is made clear and the flow of information is only across the ad-hoc placement of pages in the lineup. If a date seems wrong one can immediately diagnose its computation.

A variety of calculators might source events of specific interest to their authors. We once struggled with full moons which occur at the same time world wide. Other events like solar eclipses and satellite passes are location specific. Some events might be of sufficient duration that timezone become unimportant like the korean war or the summer of love.

This specification leaves room for exotic calculators. For example I once wrote a calculator for bonds that could interpret the specification "10 business days after the third wednesday of every month" which required knowledge of the business holidays in the place of origin.


An event is an object associated with a specific date or time range. Events are identified by an ID that is unique within a calendar. Besides a start and end date-time, events contain other data such as summary, description, location, status, reminders, attachments, etc. google

The Calagator community hopes to empower other people so they can better organize and participate in more events that support free sharing of information, open society, and involved citizenry. github


We have a go at this calculation/visualization with a plugin called Zones. github

Wiki Hangout IN US/Pacific FOR 60 minutes HERE



# Resources

Understanding Time Zones: Stop Treating the Clock Like a Number. post

Moment.js: Parse, validate, manipulate, and display dates and times in JavaScript. site

Moontool for Windows by John Walker. page