Boris Mann’s Personal Blog

Jan 2021

Tide data as a calendar subscription

My mom recently told me that the site she used to use for subscribing to an annual calendar of local tide heights and sun / moonrise times isn’t working any more:

I am stuck, trying to import this to iCal. I used to go to this site, but I cannot open the website and I don’t get an error message. And, yes, I have Internet access as I can go onto other sites.

The one below has good info but I don’t see how I can import that data into iCal.

I looked around and couldn’t really find a place where calendar subscriptions are. They all seem to be generated SEO pages with ads on them.

Xtide is available on MacOS as an app, but only has US locations and no calendar subscriptions. The command line tool tide doesn’t seem to be available for MacOS, which is what I was thinking I might be able to get raw data from.

The government of Canada has annual tide charts published as HTML tables or a PDF. Here’s the one for Point Atkinson for 2021.

I took this info and imported it into Airtable. I had to take the individual Day / Time fields – plus add year, month, and GMT Timezone offset columns – and then use a formula column with Airtable’s DATETIME_FORMAT to turn this into a “real” date column.

Then, I could use the build in Calendar view in Airtable to generate both a calendar view and a calendar subscription link.

With a little more cut and paste work, getting this all done in Airtable for one location (Point Atkinson is the spot closest to Bowen Island where my mom lives) for a one year calendar wouldn’t take that long.

I could follow the same technique to cut and paste sunrise/sunset data too.

I may investigate some web scraping tools to make this a little more scalable, and maybe turn this into a static web page.

Any other suggestions on websites that already do this or techniques to follow would be welcome :)

Also: if you have a location you’d like calendarized, send me a note: I’m happy to repeat the process!