Input Output Disconnect

I think its interesting that calendaring tools can understand the definition of complicated event reccurence rules, as well as exchange those definitions in a powerful standard format, but that the user interfaces on the tools I have used (ical, google calendar) don’t actually support creating events with anything more than the simplest recurrence relationships… Goes to show that the bottleneck in many systems is still the interface between the human and the computer.

The other day I received my first $50 parking ticket of the street cleaning season. The rules on my street, even side cleaning on the second and fourth Wednesday, odd side cleaning on the first and third Tuesday seem simple enough to follow, but I still think Somerville’s chief revenue stream must be parking violations.

I thought perhaps I can set the events in iCal, upload that file to google calendar, and get SMS reminders. Turns out one can’t specify a recurring event like second and fourth Wednesday in iCal or google calendar. iCal’s interface allows one and only one “nth day of the month” recurrence. This made me wonder – is this stuff even possible in the iCalendar format?

So I checked the iCalendar spec in RFC2445 and sure enough, it supports powerful enough recurrence rules to handle any conceivable event schedule. Here’s an example that will handle the odd side street cleaning, April through November of every year:


I edited the one 1st Tuesday rule generated by iCal in a text editor to arrive at this iCal file. Imported it back into iCal, and it rendered the recurrences perfectly. Google calendar also reads the file well even saying under details “Every first and third tuesday”.

Its a shame there’s all this underlying power, yet the user interface allows only a small sliver of it. The 80/20 rule probably dictates an organization doesn’t put in the resources to develop and support a really complicated UI for creating event reccurences, but I would think some user facing tool would support that. Are there any out there?

3 thoughts on “Input Output Disconnect”

  1. Hi James, I have the same problem (coincidentally, I’m in Somerville too), nice solution! I don’t have iCal though, and clicking on your .ics file gives a 404. Could you repost it please?

  2. Aha, I found your file with some manual editing of the link. There are some issues with links from your archived pages. Thanks!

Leave a Reply

Your email address will not be published.