explain xkcd - User contributions [en]

2739: Data Quality

2023-02-17T17:00:18Z

162.158.63.62: transcript

{{comic
| number = 2739
| date = February 17, 2023
| title = Data Quality
| image = data_quality_2x.png
| imagesize = 671x211px
| noexpand = true
| titletext = [exclamation about how cute your cat is] -> [last 4 digits of your cat's chip ID] -> [your cat's full chip ID] -> [a drawing of your cat] -> [photo of your cat] -> [clone of your cat] -> [your actual cat] -> [my better cat]
}}

==Explanation==
{{incomplete|Created by a SUPERIOR FELINE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
Data are transferred in bits, and {{w|data loss}} is the process by which some of these bits are lost or otherwise unfavourably altered during data transport.

This comic shows a chart in the form of a line, moving in increasing quality from most lossy to most lossless.

The title text uses your cat as an example of this range of losses (or, in the case of the latter reaches of the graph, gains) in the data. The most lossy is an exclamation about how cute your cat is, which is ephemeral and obviously carries very little significance in terms of actually providing specific, transferrable information about your cat. The example then progresses into your cat's chip ID; presumably your cat has been microchipped, and between the last four digits (commonly used in sensitive information as an identifier without revealing the full number) or the entire chip ID, provides a still-uninformative yet slightly improved way of identifying your cat. A drawing of your cat and a photo of your cat would portray the cat reasonably well, while a clone of your cat and (of course) your actual cat would be the best way of gaining data about your cat. However, as in the actual comic, the final, most lossless (in this case, with the most gain) form of data transfer has nothing to do with your cat, but is simply Randall's better cat. This is apparently made out by Randall to be the pinnacle of cat data.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
[Caption above the chart]: DATA QUALITY
[An arrow pointing right is shown under the caption.
[Below the caption and arrow a number-line like chart is shown. Above the center of the line, two words are displayed, separated by a dotted vertical line:]
Lossy|Lossless
[Below the number line, phrases are placed at each of the 8 unevenly-spaced hash marks. From left to right, they are:]
Someone who once saw the data describing it at a party
Bloom filter
Hash table
JPEG, GIF MPEG
[[[TBC]]]

{{comic discussion}}

2463: Astrophotography

2021-05-26T14:41:41Z

162.158.63.62:

{{comic
| number = 2463
| date = May 14, 2021
| title = Astrophotography
| image = astrophotography.png
| titletext = [One hill over, a competing astrophotographer does a backflip over a commercial airliner while throwing a tray of plastic space stations into the air, through which a falcon swoops to 'grab' the real one.]
}}

==Explanation==

{{w|Astrophotography}} is the practice of taking pictures of astronomical objects. Sometimes it is specified as a hobby, as opposed to the work of professional astronomers. Astrophotographers like to take pretty pictures of all sorts of objects in the sky, but photographing the {{w|Sun}} is a popular subgenre within the field, especially if something is transiting in front of it. Typical things include planes, the {{w|International Space Station}} (ISS), and the {{w|Moon}} ({{w|Solar eclipses}}).

During the [[:Category:Total Solar Eclipse 2017|Total Solar Eclipse 2017]] visible across US it was possible to see the ISS pass in front of the Sun during a partial part of the Eclipse (from a site that was later in the total Eclipse zone.) This was [https://www.smartereveryday.com/eclipse photographed] and filmed by Destin from Smarter Every Day and can be seen in his video [https://www.youtube.com/watch?v=lepQoU4oek4&feature=youtu.be Space Station Transiting 2017 ECLIPSE]. (Go to the time of the flyby of the ISS in the video [https://youtu.be/lepQoU4oek4?t=209 here]).

Two years later he did another episode [https://www.youtube.com/watch?v=Nk0MRxXqo9s South American Eclipse - Argentina]. In this video there was only the moon eclipsing the sun, at first, but then [https://www.youtube.com/watch?v=Nk0MRxXqo9s&t=610s towards the end] the sun begins to set behind the distant mountains creating a shadow scenario between Moon and mountain shadows as displayed in this comic.

This comic thus combines those two videos, which Randall must have seen, and then adds several more layers caused by the Astrophotography community's One-Upmanship. The practice of "one-upmanship" refers to the practice of achieving something superior to what another has achieved, or "getting one up on" them. The term originated in the 1950s or earlier.

The caption claims that the photo shown in the comic is the result of a continuous string of one-upmanship among astrophotographers in a community, each striving to one-up the other.

In this comic there seems to be an abundance of things:
* The ISS can be seen transiting in the upper center. (as in [https://apod.nasa.gov/apod/ap210504.html this picture])
* There is an ongoing {{w|partial solar eclipse}} so the view of the Sun is partially obscured by the Moon in the upper right quadrant.
**These two things are what Destin managed in his first video.
* The Sun is setting or rising from behind a hill while partially eclipsed.
** This is what Destin managed in his second video.
* This photographer achieved a combination of those two plus several other ones-up those two videos.
* [[Megan]] is standing slightly below the peak of a hill and seems to be juggling, with five balls, which are also in front of the sun. One or more of those balls might actually be {{w|sunspots}} or the planets Mercury or Venus.
* [[Cueball]] is standing at the peak of the hill, shooting an arrow from a bow, one arrow has pierced what at first appears to be one of the juggling balls, but may be a {{w|Transit of Venus}}.
** A simultaneous Eclipse and Transit of Venus is actually expected in the future, but not until April 5, 15232 (13211 years after the publishing of this comic).
*** It would though likely be easier to make the arrow "hit" Venus than one of the juggled balls, as the planet's angular velocity is significantly lower.
*** The other four balls are too large that any of them could represent Mercury, the only other planet that can transit the Sun, when seen from Earth. But Megan has been careful to make one ball go so much higher than the middle two, that it seems to fit that Venus has been shot out from between them.
** Given the long time before this could happen, it could also just be five balls. And in that case the easiest way to make this picture is to put the fifth ball on the arrow before shooting it.
* Two airplanes pulling banners with the words "nice" and "shot" (which could refer to both the archer and the photographer) are flying in opposite directions above them. (Airplane banners that are not continuous sheets are made with thin support lines spanning the openings, which explains the presence of the apparently unsupported central disc in the "O".)

Taking the picture required precisely scheduling and arranging the relative positions of several of the various subjects (and photographer) to coincide with the predictable but rare conjunctions of the rest of the scene, as well as special equipment:
* All this had to be timed very very precisely as the [https://youtu.be/lepQoU4oek4?t=209 transit of the ISS only takes a second].
* A solar filter must be used to photograph the sun without overexposing the image or even damaging equipment.
* The photograph must be taken during a partial solar eclipse. These only happen a few times per year and are only visible in part of the world.
* Related to the last point, a nearby person appears larger than the moon. It is possible to photograph the silhouette of a person or a cityscape in front of a full moon, making the moon look comparatively larger or smaller by adjusting the distance to the closer subject, and then the lenses used by the photographer to make them both fill just the right amount of the frame. The photographer needed to carefully choose their position relative to the subjects to make this happen.
* The exposure time of the photograph had to be short enough to capture clear silhouettes of the ISS, the juggling balls and the arrow while these were in the air.
* The mountain had to be in a location that would happen to see the ISS passing in front of the sun at the same time as the sun was rising from behind it.
* The subjects had to achieve a moment in which four juggling balls were in the air and an arrow had pierced the point where Venus would appear, while sideways relative to the sun's light, with still near normal intensity.
* The planes also needed to be flying in the correct directions for the text of the signs to be visible, and with very precise timing for them to be in the correct positions to read "Nice" as coming before "Shot" just as the ISS passes by.
* The sky (at least between the photographer and the Sun) had to be free of clouds.

The title text describes a similarly outlandish photo attempting to one-up Cueball and Megan, done simultaneously on the next hill over, thus a place where the same ISS transit can be seen:
* A commercial airliner is flying in front of the Sun, thus this has to be timed with the flight plan (or it has to be chartred, to pass there at the correct height and position, within a few seconds.
* The astrophotographer is performing a backflip such that they appear to be over the airliner.
* The astrophotographer is tossing several tiny models of the ISS from a tray, so they also appear in front of the Sun with the real one (like the joggling balls and Venus).
* A falcon is flying in front of the Sun, presumably intending to capture prey, in such a way that it appears to be snatching the real ISS out of the fakes. The falcon moves slowly compared to the ISS, so it just needs its talons to be on the line the ISS makes across the Sun, then a picture where it is close to the talons can be used. The other parts are slower than this.

==Transcript==
:[Cueball and Megan stand on a hill with the dark yellow sun setting behind them. Outside the Sun's disc everything is black. All that can be seen is silhouettes against the sun. Cueball is at the top-left of the hill, holding a bow in his left arm, which has been recently shot, as indicated with lines along the string. The the arrow is to right, where it has speared a ball. Megan is at the bottom-right of the hill, juggling four other balls, one near her hand, two above her and one higher up than the path of the arrow. There are two planes going in opposite directions with banners on them with words readable against the Sun. Above the planes is the shadow of the International Space Station. Finally Sun is partially eclipsed by the moon in the upper right corner.]
:[Banner 1]: Nice
:[Banner 2]: Shot

:[Caption beneath the panel]:
:Our astrophotography community's one-upsmanship[sic] is getting out of hand.

==Trivia==
*Randall has commented on extreme photography in comics [[1855: Telephoto]] and [[1719: Superzoom]], and the ''How To'' chapter "How to take a selfie".

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Space]]
[[Category:Animals]]

Talk:2353: Hurricane Hunters

2020-09-03T00:38:09Z

162.158.63.62:

St. Louis people coming here to see if it's coincidence or if Randell was using location services for the destination.

Where did the stuff on the desk go?
:Well, Black Hat ''is'' present in the room... [[Special:Contributions/162.158.103.141|162.158.103.141]] 16:27, 31 August 2020 (UTC)
: Squirrels.
: [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 17:36, 31 August 2020 (UTC)

Re: St. Louis - I'm not in St. Louis, but it still reads St. Louis for me. [[Special:Contributions/108.162.219.90|108.162.219.90]] 17:02, 31 August 2020 (UTC)

Considering the rock-bottom prices offered by airlines recently ($15 for a ticket on Delta or United?!?), it might not be too hard to fill a plane with people who just want to go on a dangerous joyride in a 747. Let's try some loops!
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 17:39, 31 August 2020 (UTC)

Reminds me of https://youtube.com/watch?v=zmKXC9CYZwU (the aerobatics part). [[Special:Contributions/162.158.155.36|162.158.155.36]] 19:11, 31 August 2020 (UTC)

Is it purposeful that the description includes a line from the Hamilton song "Hurricane"? ("In the eye of a hurricane, there is quiet for just a moment, a yellow sky.")
:"(In the) eye of a hurricane(/storm/cyclone/...)"? A fairly standard phrase, at ''least'' since we had satellite photos to get a large enough overview of prime examples; though a well-defined eyewall (if survived) probably gave everyone the appreciation of the 'arena effect' in that time between the eye passing over them and then departing (requiring further survival) that could bring even primitive man the concept of an 'eye' in the weather. Tried to track down first usage. [https://www.oed.com/viewdictionaryentry/Entry/67296 OED] seems to give us "1758 J. Adams tr. A. de Ulloa Voy. S.-Amer. II. ii. iii. 213 The cloud..begins, according to the sailors phrase, to open its eye, i.e. the cloud breaks, and the part of the horizon where it was formed becomes clear.", though whether that's referencing the centre of a full hurricane or not, I don't know... [[Special:Contributions/141.101.98.70|141.101.98.70]] 03:27, 1 September 2020 (UTC)

I don't think that Black Hat as a jet pilot would go to prison in real world. I think he would DIE in his attempt and they rarely put dead people in prison, especially if the body wasn't found. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 03:53, 1 September 2020 (UTC)
:Don't think he particularly cares. Beret Guy probably would survive, but he'd just hallucinate the bars away. Cueball would make the control panel flash some weird error before taking off.

:This feels weirdly fun, actually. [[User:Bubblegum|bubblegum]]-[[User_talk:Bubblegum|talk]]|[[Special:Contributions/Bubblegum|contribs]] 06:05, 1 September 2020 (UTC)

:I updated the line. Really I thought black hats didn't go to prison because they kept themselves anonymous, but instead I mentioned security firms and organized crime. [[Special:Contributions/162.158.63.62|162.158.63.62]] 00:38, 3 September 2020 (UTC)

For people who would like to read what that job is on a bad day: https://tailspinstales.blogspot.com/2011/05/hunting-hugo.html lG Tier666 (who has lost his password...)[[Special:Contributions/108.162.229.142|108.162.229.142]] 10:37, 1 September 2020 (UTC)

2305: Coronavirus Polling

2020-05-11T20:44:38Z

162.158.63.62:

{{comic
| number = 2305
| date = May 11, 2020
| title = Coronavirus Polling
| image = coronavirus_polling.png
| titletext = If you want to see the polling questions we agree on MOST, you can check out Chapter 24 of my book How To, where I got the Roper Center on Public Opinion Research to help me design the world's least electable political campaign platform.
}}

==Explanation==
{{incomplete|Created by an ONLINE POLL. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic, another comic in the [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus outbreak|2020 COVID-19 pandemic}}, compares opinion polling of COVID-19 related topics to polling of other, unrelated topics. Opinion among Americans is remarkably unisonous on necessary measures concerning the COVID-19 pandemic. To put this unanimity in perspective, polls on other topics are shown with similar high percentages of unanimity but now always on extremely uncontroversial questions like liking apple pie or Tom Hanks, or the importance of elections to democracy.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

[Caption at the top]

It's hard to get people to agree on '''''anything''''' in polls.

But we all agree about the coronavirus.

Here's how americans feel about COVID-19, along with other topics that get similar levels of agreement for comparison.

[Smaller caption]

Compiled with help from HuffPost polling editor Ariel Edwards-Levy. Sources: xkcd.com/2305/sources

[Left column]

Recent coronavirus polls

86% say "stay at home orders are responsible government policies that are saving lives" rather than "an over-reaction" (ABC/IPSOS)

85% oppose reopening schools (NPR/MARIST)

91% oppose resuming big sporting events (NPR/M.)

85% trust local health officials and health care workers (AXIOS/IPSOS)

93% are trying to maintain 6-foot distances while in public (AXIOS/IPSOS)

81% say americans should continue to social distance as long as is needed to stop the coronavirus even if it means continued damage to the economy (Politico/Morning Consult)

[Right Column]

Other Polls

81% enjoy apple pie (HuffPost/YouGov)

76% feel positively about kittens (HuffPost/YouGov)

84% have a favorable impression of Tom Hanks (IPSOS 2018)

89% say fair elections are important to democracy (PEW)

86% feel positively towards Betty White (IPSOS 2011)

86% do not trust Kim Jong-Un to do the right thing (PEW 2019)

64% are concerned about the emergence of "murder hornets" (YouGov)

{{comic discussion}}
[[Category: COVID-19]]
[[Category: Food]]
[[Category: Bees]]
[[Category: Animals]]
[[Category: Comics featuring real people]]
[[Category: Comics featuring politicians]]
[[Category: How To]]