Saturday, May 16, 2020

What's an hour?

This morning a couple of ovenbirds crashed into our kitchen deck-door glass. The one on its side righted itself after a couple of minutes and they both just lay there in obvious shock. Here's a closeup of the upright one:

Catherine looked it up and said to just leave them for a few hours. And indeed, three hours later they were gone. This has happened before, twenty or more years ago (I am guessing), and — somewhat remarkably — the two birds that crashed into the door back then were also ovenbirds!

When I downloaded the photos for this article, I noticed that the time-stamp didn't seem right. I soon realized that I had forgotten to set the daylight-saving time option on my camera back on March 8. Which meant that I had 209 recent photos in my Apple Photos app that needed to be adjusted by one hour. Fortunately, Photos makes this easy. Unfortunately, the app hung ~70% through the process:

So I force-quit and relaunched the app to see what had been accomplished. I could see that some of the photos had added the hour but many had not. Worse, Photos had not gone through the 209 photos sequentially by date, but rather, somewhat haphazardly — a few each day. This is no doubt some sort of optimization procedure that utilizes multiple cores for speed gain (the same thing happens when one is importing photos from the camera). What Apple Photos did not realize is that my Mathematica was already utilizing all four cores on my Mac to calculate a ParallelTable. Perhaps this is why the application crashed.

Anyways, I now had to step through each day's photos and try to determine which ones had been adjusted and which had not. I had the camera's sequential photo numbers and the fact that many of the shots had been taken within minutes of each other to help me in this endeavour. However, for days (and parts of a day) where I had only taken one photo, this did not help. It took me another hour or so to step through my backup and check each photo's original time. Only later did I notice that the get-info on even the modified-time photos still showed the original time stamps.

All in all, it took me longer, I think, to correct all that Exif (when did they stop using all-caps?) data than it took those birds to recover. Moreover, I had to add an hour to the "posted" time on my Echo Beach post because I had originally cheated by back-timing that post to match the then-thought-to-be-correct photo time (to give it a more stream-of consciousness feel).

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