Comment by qwertox | Hacker News Reader

Comment by qwertox | Hacker News Reader

It took me a bit to understand that it's just the red line from the entire dome. It makes me a bit sad that so much information is discarded for these keograms. Isn't there a way to "peel" the image in such a way that the entire image ends up being the line? Like spiraling or something like that from the outer "rim" to the center point.

Nevertheless, it's the first time I've seen this and liked the project a lot. I've seen this from normal images, but not from such a fisheye lens.

Really cool project.

Edit:

Looking at https://victoriaweather.ca/keogram.php?photo=20120810.jpg how can this contain the entire landscape if only the center line is used, which is supposedly always the same line? I mean, the camera isn't rotating. Is this just another kind of view generated from the dataset?

The goal of the keogram is to give a quick overview of sky conditions so you can see if there were clouds, aurora, or other interesting activity. No information is discarded, as the user keeps all of the data, the keogram is just a way of identifying which pictures might have something interesting.

The year long keogram presents even less data, as it's just the centerline of the keogram for each day. So, essentially just the center pixel of each image. Still gives a good overview of what the sky conditions were like throughout the year.

The landscape picture there in your link is a different kind of thing; that one has the column used from each individual photo/frame advance from left to right through the day when constructing the final image, so it still looks like the same static view of the landscape. Of course it's also just a different camera view entirely as well.

The fixed column (and upward view) approach used in the main link is better for showing the movement of the sun/moon/stars.

I want a movie made from rotating that red line.

But there are lots of images throughout the day.

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