Charlie Loyd @vruba@everything.happens.horse

Okay, here we are: https://gist.github.com/celoyd/f163e6e582d87a50a6d37743e840dcb8

Posted while running out the door to carve pumpkins. There are probably a few TKs and such, and I didn’t spellcheck it. (Visual Studio Code doesn’t do that, apparently, at least on Ubuntu?)

Should I finish a devlog about this even though it’s getting a bit out of hand and probably makes errors about the math I had to learn?

They should make a kind of linear algebra that I can enjoy.

Very few people should implement all of ISO 8601 – it’s more complex than you might think – and I have reservations about recommending any standard that isn’t freely available anyway, but RFC 3339 is right there. Right there! And it’s really good!

Sometimes when I’m a joyless pedant about using SI units, formatting them in standard ways, etc., I’m dialing it up to 130% and making a little bit of fun of myself and others.

This time, I’m actually mad. Don’t do this kind of thing. https://mastodon.social/@lorentey/111263794546558934

The Seattle area at night, in color, from a stack of Landsat 9 scenes. Denoised with some clumsy FFT editing. I can’t imagine why you would use this for anything over one of many other options, but it’s neat that it works.

I say objectively overkill because Euler was computationally faster, even though it took a few more steps.

Also, there’s a really wide range of h parameters that are tied for optimality. Taken together, this makes me think that it’s the lumpiness of the topography that’s the main limit here. But I’m in way over my head mathematically, so I could easily be misimplementing or misinterpreting.

Anyway, this is easily the silliest thing I’ve ever done with ground control points.

Various fixes. It now uses fourth-order Runge–Kutta integration to place the labels, which is objectively overkill and also I probably put many bugs in it, but I had fun and that’s the important thing.

Forgot to add the warning: this is intended for, and only tested on, desktop browsers.

Weekend project (do not look at the source): https://sat9.land/x/swath/#0,25500

As a non-JS person who wrote a moderate amount of JS a long time ago and a little JS in the last few days, it feels like it’s been kintsugi-ed. It can never be so completely fixed that you won’t see how it was broken, but it can certainly become an open meditation on the nature of repair.

Woke up to a @aworkinglibrary newsletter.

I think this is important work done well, but I will complain about the headline: it’s really hard to define “visible from space” in a way that makes sense and matches what any two people think it means. Stop using it this way. https://www.npr.org/2023/10/06/1203372829/the-bruising-artillery-battle-in-ukraine-has-left-a-scar-that-is-visible-from-sp

I am very internet-oriented and generally think it’s good when things are available digitally, but the idea that someone has to use expensive hardware, proprietary software, etc., to receive the official time signal is sad.

Trying to get all the household’s clocks and watches synced to the CBC/NRC time signal was an extremely entertaining project in like 1996.

Over-the-air civil broadcasts that require only amateur radio knowledge to decode from scratch seem worth keeping alive. I hope that tide comes back in one day.

https://www.cbc.ca/news/canada/ottawa/cbc-stops-broadcasting-national-research-council-long-dash-time-signal-1.6988903

At its core, doing anything with geodetics is basically (1) very straightforward math that you can derive in your head from the Wikipedia illustration of trigonometric functions, plus (2) several hours of figuring out what φ means in this case and which definition of “up” the author is assuming.

Lest anyone think I’m making up the Greek letters.

And to be fair, sometimes you also see λ. That’s great because λ is equivalent to l, so it stands for the one of longitude and latitude that starts with l.

Notation for latitude and longitude is easy and people should stop being annoyed by it.

Simply use order (either the lat, lon convention or the lon, lat convention).

If you need cross-linguistic symbols for an equation, use the Greek letters (either the θ = latitude, φ = longitude convention or the θ = longitude, φ = latitude convention).

Personally, I find it clearest to just abbreviate them, so l = longitude and l = latitude.