explain xkcd - User contributions [en]

Talk:700: Complexion

2015-09-11T04:04:29Z

199.27.128.184:

I'm not sure, and I don't have the free time to check, but isn't "Heads, she gets the--" the beginning of what Dent said? --[[User:Athang|Athang]] ([[User talk:Athang|talk]]) 04:06, 20 March 2014 (UTC)

"Two Face" is also standing next to one girl with light hair, and one with dark hair. Sugar and Spice? [[Special:Contributions/199.27.128.184|199.27.128.184]] 04:04, 11 September 2015 (UTC)JubileeJones

1520: Degree-Off

2015-05-08T16:37:06Z

199.27.128.184:

{{comic
| number = 1520
| date = May 4, 2015
| title = Degree-Off
| image = degree off.png
| titletext = I'M SORRY, FROM YOUR YEARS OF CONDESCENDING TOWARD THE 'SQUISHY SCIENCES', I ASSUMED YOU'D BE A LITTLE HARDER.
}}
==Explanation==
[[Cueball]] (physics), [[Hair Bun Girl]] (biology), and [[Megan]] (chemistry) appear to be on a talk show called Degree-Off, hosted by [[Hairy]], where representatives of different fields, try to explain why their field is the best and why to get a degree in their field. The title "Degree-Off" is a portmanteau of "{{w|Academic degree|degree}}", as in the recognized completion of studies at a school or university, and "{{w|face-off}}", a direct confrontation between two people or groups. Since there are three participants, this is not a true face-off, unless Megan, who does not speak, is not counted.

The host asks the physicist Cueball to go first. He light-heartedly begins to tell what appears to be long story, beginning with a {{w|Richard Feynman}} anecdote. During the {{w|Manhattan Project}} in Los Alamos, Richard Feynman got bored because of the isolation and started learning {{w|lock picking}} on the secret documents safes. Using these new skills, he played lots of pranks on his colleagues, like leaving notes and spooking them into believing there was a spy among them (which, of course, {{w|Klaus_Fuchs|there was}}). He finishes his case with [http://en.wikiquote.org/wiki/Ernest_Rutherford a quote] from {{w|Ernest Rutherford}}, implying that his speech was quite long and winding. The quote communicates the idea that physics is the only fundamental framework, so that the job of chemists, biologists and other scientist simply is to catalog and systematize observations ("collect stamps") on phenomena too complicated to presently be fully described in terms of physics. This idea was earlier lampooned by [[Randall]] in [[435: Purity]].

The biologist, Hair Bun Girl, goes next, showing with a graph (see below) that the field of biology has helped reduce disease. She then goes on to claim that the heroes in biology (the part known as Medicine) has even "slain" one of the {{w|Four Horsemen of the Apocalypse}}. Originally these were Conquest, War, Famine and Death, but in popular culture Conquest is usually re-interpreted as {{w|Four_Horsemen_of_the_Apocalypse#As_infectious_disease|Pestilence}} - Hair Bun Girl implies that the field of biology has almost eliminated Pestilence. (The imagery of Pestilence being thwarted by modern medicine was also used in the book {{w|Good Omens}}, by {{w|Terry Pratchett}} (of whom Randall is a fan, see [[1498: Terry Pratchett]]) and {{w|Neil Gaiman}}, where Pestilence has retired after the discovery of {{w|Penicillin}}, and been replaced by {{w|Pollution}}.)

<div class="toccolours mw-collapsible mw-collapsed">
This graph shows the death rate from infectious disease in USA, similar to that shown in the comic presented by Hair Bun Girl, as both have the range of 1900-2000. The spike is attributable to the {{w|1918 flu pandemic}}. The graph has been published in this paper [http://jama.jamanetwork.com/article.aspx?articleid=768249 Trends in Infectious Disease Mortality in the United States During the 20th Century].
<div class="mw-collapsible-content">[[File:Crude_Infectious_Disease_Mortality_Rate_in_the_United_States_from_1900_Through_1996.gif]]</div>
</div>

Hair Bun Girl then goes on to directly accuse Cueball (i.e. physicists) of creating a new Horseman to replace the one slain by the biologist. She claims that they gathered in the desert to do so. Given Cueball's opening remark, she must be referring to the development of the {{w|atomic bomb}}, which was built and tested in the {{w|New Mexico desert}}. The new horseman is therefore the atomic bomb, or the various perils associated with it.

Hair Bun Girl's implied condemnation of the physics community has been echoed by some of the scientists involved in the project itself. After the test detonation of the first nuclear weapon on July 16, 1945, {{w|J. Robert Oppenheimer}}, the director of the the {{w|Los Alamos National Laboratory}}, found himself quoting the {{w|Bhagavad Gita}}: "Now I am become Death, the destroyer of worlds."

This harsh moral judgement shocks Cueball, who exclaims "I thought this was supposed to be fun and lighthearted!" While the set-up is of a frivolous friendly competition, Hair Bun Girl's presentation is surprisingly dark. Her retort in the final panel reveals that she was angered by the off-hand dismissal of 'soft' sciences as "stamp-collecting", and turned the game from a light-hearted fun into something more disturbing.

In the title text the biologist goes on to declare in {{w|All caps}} that she is surprised a physicist isn't "harder", after all their condescending towards the "squishy" sciences. The use of 'hard' and 'squishy' is a play on the colloquial division between the so-called 'hard' sciences (such as physics and chemistry) and 'soft' sciences (such as biology and geology). 'Hard' sciences usually refer to the perception that in fields like physics, precisely repeatable experiments and measurements are possible, as opposed to 'soft' sciences seen as placing less emphasis on precisely quantifiable predictability - however Hair Bun Girl is extending 'hard' to it's meaning of 'stoic', mocking Cueball for not being able to weather a personal moral attack. Again she is indicating that she's upset by directly referencing a mocking portrayal of other fields allegedly made by Cueball.

In [[520: Cuttlefish]] Randall shows that he personally respects biologists - or at least fears them.

==Transcript==
:[Hairy is acting as the host of a TV talk show, ''Degree-Off''. Cueball, Hair Bun Girl, and Megan are acting as representatives of Phys (Physics), Bio (Biology), and Chem (Chemistry) respectively. They each stand behind their own Lectern with the respective subject label.]

:Hairy: Welcome to the ''Degree-Off'', where we determine which field is the best! Physics, wanna go first?
:Cueball: Sure! I'd like to tell the story of Richard Feynman's Manhattan project lockpicking pranks...

:Cueball: ...and as he said, "all science is either physics or stamp collecting."
:Cueball: Thank you.
:Hairy: ''Great!'' Bio, you wanna go next?
:Hair Bun Girl: Okay.

:[A graph labeled "Per 100,000 is shown above Hair Bun Girl]
:Hair Bun Girl: This is a graph of the death rate from infectious disease in this country.

:[Hair Bun Girl raising her left hand]
:Hair Bun Girl: The heroes of my field have ''slain'' one of the four horsemen of the apocalypse.

:[Hair Bun Girl pointing at Cueball]
:Hair Bun Girl: While the heroes of ''your'' field gathered in the desert to create a new one.

:Cueball: ...Jeez, what the hell? I thought this was supposed to be fun and lighthearted!
:Hair Bun Girl: ''You must have been thinking of stamp collecting.''

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Hair Bun Girl]]
[[Category:Science]]
[[Category:Charts]]
[[Category:Physics]]
[[Category:Biology]]
[[Category:Portmanteau]]

977: Map Projections

2015-02-16T23:37:08Z

199.27.128.184: oops misspelled Dvorak

{{comic
| number = 977
| date = November 14, 2011
| title = Map Projections
| image = map_projections.png
| titletext = What's that? You think I don't like the Peters map because I'm uncomfortable with having my cultural assumptions challenged? Are you sure you're not... ::puts on sunglasses:: ...projecting?
}}

==Explanation==
{{w|Map projection}}, or how to represent the spherical Earth surface onto a flat support (paper, screen...) to have a usable map, is a long-time issue with very practical aspects (navigation, geographical shapes and masses visualization, etc.) as well as very scientific/mathematical ones, involving geometry or even abstract algebra among other things. There is no universal solution to this problem, any 2D map projection will always distort in a way the spherical reality; many projections have been proposed in various contexts, each intending to minimize distortions for specific uses (for nautical navigation, for aerial navigation, for landmass size comparisons, etc.) but having drawbacks from other points of view. Some of them are more frequently used than others in mass media and therefore more well-known than others, some are purely historical and now deprecated, some are very obscure, etc.

[[Randall]] suggests here the idea that someone's "favorite" map projection can reveal aspects of their personality, then goes through a series of them to show what they can mean:

;Mercator
[[File:MercatorProjection.jpg|frame|The Mercator projection]]
:The {{w|Mercator projection}} was introduced by Flemish cartographer Gerardus Mercator in 1569. The main purpose of this map is that at any point the vertical and horizontal scales are the same, so locally i.e. considering only a small part of the map, geographical features (shapes, angles) are well represented, which helps a lot in recognizing them on-the-field, or for local navigation in that small part only. For this reason, that projection (or a close variant) is used in several online mapping services, such as Google Maps, which means that it is frequently encountered by the general public. No angle distortion also means that a straight line on the map corresponds to a course of constant bearing (direction), which was very useful for nautical navigation in the past (and thus made that projection very well-known).

:However, from a global point of view, this projection is radically incorrect in how it shows the size of landmasses (for instance Antarctica or Greenland seem gigantic), and furthermore, it always excludes a small region around each pole (otherwise the map would be of infinite height), so it doesn't provide a complete solution for the problem of map projection. The comic implies that people who like that projection aren't very interested with map issues, and typically use what they are offered without thinking much about it.

{{clear}}

;Van der Grinten
[[File:VanDerGrintenProjection.jpg|frame|The Van der Grinten projection]]
:The {{w|Van der Grinten projection}} is not much better than the Mercator. It was adopted by {{w|National Geographic}} in 1922 and was used until they updated to the Robinson projection in 1988.

:The Van der Grinten projection is circular as opposed to the Mercator projection. Circles look happier than squares, leading to the conclusion that people who like the projection are optimistic.

{{clear}}

;Robinson
[[File:RobinsonProjection.jpg|frame|The Robinson projection]]
:The {{w|Robinson projection}} was developed by {{w|Arthur H. Robinson}} as a map that was supposed to look nice and is often used for classroom maps. National Geographic switched to this projection in 1988, and used it for ten years, switching to the Winkel-Tripel in 1998.

:{{w|The Beatles}} was a rock band that enjoyed great commercial success in the 1960s. The Beatles, coffee, and running shoes suggest an ordinary, easygoing lifestyle paralleled by the projection.

{{clear}}

;Dymaxion
[[File:DymaxionProjection.jpg|frame|The Dymaxion projection]]
:Also called the Fuller Map, the {{w|Dymaxion Map}} takes a sphere and projects it onto an icosahedron, that is a polyhedron with 20 triangular faces. It is far easier to unwrap an icosahedron than it is to unwrap a sphere into a 2D object and has very little skewing of the poles.

:Randall associates the projection to geek subculture and niche markets:
:*{{w|Isaac Asimov}} was an American science-fiction writer, that (as well as publishing many textbooks) is considered the father of the modern concept of robots. He invented the {{w|Three Laws of Robotics}}. He also worked on more than 500 books throughout his career.
:*{{w|XML}} is the eXtensible Markup Language. It is used to represent data in a format that machines can read and understand, as well as being human-readable. In practice, XML is cumbersome to read.
:*{{w|Vibram FiveFingers|Toed-Shoes}} are a [[1065: Shoes|favorite]] of Randall's to pick on. In society they are seen as a {{w|geek}} clothing item.
:*Brought to the world by {{w|Dean Kamen}}, the {{w|Segway PT}} was supposed to be a device that changed the way cities were built. In reality, most principalities have put in place rules specifically against Segways, making them a frustration to own and use within the law (in some states in Australia, it is illegal to use them on public footpaths or roads). Also, the former owner of {{w|Segway Inc.}}, the late {{w|Jimi Heselden}}, accidentally rode his Segway off a cliff in 2010.
:*{{w|Virtual reality|3D goggles}} are a very niche market only pursued by enthusiasts. In the 1990s the promise of virtual realities was very tantalizing; many companies attempted to perfect it, but fell short of the mark. Also, the phrase "The grass is always greener on the other side of the fence" is relevant.
:*{{w|Dvorak Simplified Keyboard|Dvorak}} is an alternate keyboard layout to QWERTY. According to legend, QWERTY was invented to help keep manual typewriters from jamming (by placing the most used keys far from each other) but Dr. {{w|August Dvorak}} performed many studies and found the mathematically optimal keyboard layout to reduce finger travel for right handed typists. While some claim Dvorak is technically better than QWERTY, QWERTY had become the standard. All the keyboards were laid out in QWERTY format, and retraining the brain after becoming a touch typist is extremely difficult.

{{clear}}

;Winkel-Tripel
[[File:Winkel-TripelProjection.jpg|frame|The Winkel Tripel projection]]
:Proposed by {{w|Oswald Winkel}} in 1921, this map tried to reduce a set of three (German: Tripel) main problems with map projections: area, direction, and distance. The {{w|Kavrayskiy VII projection|Kavrayskiy projection}} is very similar to the Winkel Tripel and was used by the USSR, but very few in the Western world know of it.

:The comic links this projection to {{w|hipster}} subculture. The hipster stereotype is to avoid conforming to mainstream fashions. "Post-" refers to a variety of musical genres such as {{w|post-punk}}, {{w|post-grunge}}, {{w|post-minimalism}}, etc. that branch off of other genres.

{{clear}}

;Goode Homolosine
[[File:GoodeHomolosineProjection.jpg|frame|The Goode Homolosine projection]]
:The {{w|Goode homolosine projection}} takes a different approach to skewing a sphere into a roughly circular surface. An orange peel can be taken from an orange and flattened with fair success; this is roughly the procedure that {{w|John Paule Goode}} followed in creating this projection. Randall is suggesting that people who like this map also prefer relatively easy solutions to other things in life, despite those solutions having nuanced problems that are more difficult to address.

:Common people make arguments that if normal people would run the United States, then the US wouldn't be in the trouble it is. This is from the belief that career politicians are simply out to make money and will only act in the interest of their constituency when their continued easy life is threatened (usually around election time).

:Airline food is another, much maligned, problem. How do you store enough food to feed people on long airplane trips? The common solution is to use some kind of sub-standard microwaveable dinner. Randall is saying that the people in favor of the Goode Homolosine wonder why the airlines don't simply order meals from the restaurants in the airport, store that food, and serve it, rather than using frozen and microwaved food.

:Older cars burned oil like mad fiends, and oil back then would become corrosive to the innards of an engine, so oil had to be changed often. But, with the introduction of synthetic motor oil and better designed engines, new cars only need their oil changed about every 10,000 to 15,000 miles. A common conspiracy theory is that modern automobile oil manufacturers still recommend that car owners change their oil every 3,000-5,000 miles to "drum" up more business, even though that frequency is unnecessary.

:All of these references suggest that people who like the Goode Homolosine projection are fans of easy solutions to problems. However, the solutions would not necessarily work in practice. For instance, the restaurants might have trouble making enough food for the whole plane, and it could get cold before being served. Also, the air conditions [http://www.nbcnews.com/health/one-reason-airline-food-so-bad-your-own-tastebuds-6C10823522 aboard planes] can affect taste, so airlines say they optimize for this. And there is no such thing as a "normal" person, and if there were, he/she would have virtually no chance at actually getting into government office.

{{clear}}

;Hobo-Dyer
[[File:Hobo-DyerProjection.jpg|frame|The Hobo-Dyer projection]]
:The {{w|Hobo–Dyer projection}} was commissioned by Bob Abramms and Howard Bronstein and was drafted by Mick Dyer in 2002. It is a modified {{w|Behrmann projection}}. The goal was to be a more visually pleasing version of the Gall-Peters.

:As is discussed in the Gall-Peters explanation, the Gall-Peters was developed to be equal area, so that economically disadvantaged areas can at least take comfort in the fact that their country is represented correctly by area on maps.

:Randall associates the Hobo-Dyer projection to "crunchy granola" — a stereotype associated with vegetarianism, environmental activism, anti-war activism, liberal political leanings, and some traces of {{w|hippie}} culture.

:With the new general acceptance of homosexual, bisexual, and transgender persons, some have begun to invent gender-neutral pronouns so that when referring to a person whose gender is not known they cannot be offended by being referred to by the wrong pronouns. In {{w|Middle English}} 'they' and 'their' were accepted gender-less pronouns that could replace 'he', 'she' as well as be used to represent a crowd, but this usage is considered by some to be grammatically incorrect because of the plural/singular debate ([http://www.merriam-webster.com/video/0033-hisher.htm stupid Victorian Grammarians!]). None of the {{w|gender-neutral pronoun#Invented_pronouns|many attempts at popularizing gender-neutral pronouns}} have achieved any degree of success in the mainstream.

:Randall seems to associate the Hobo-Dyer projection with the Social Justice movements on social media sites such as Tumblr.

{{clear}}

;Plate Carrée
[[File:PlateCarreeProjection.jpg|frame|The Plate Carrée projection]]
:Also known as the {{w|Equirectangular projection}} has been in use since, apparently, 100 AD. The benefit of this projection is that latitude and longitude can be used as x,y coordinates. This makes it especially easy for computers to graph data on top of it.

:According to the comic, the projection appeals to people who find much beauty in simplicity.

{{clear}}

;A Globe!
[[File:GlobeProjection.jpg|frame|The Globe "projection"]]
:In any good discussion there has to be at least one smart-ass. This is a comic about map projections, that is, the science of taking a sphere and flattening it into 2 dimensions. The smart-ass believes that we shouldn't even try: a sphere is, tautologically, the perfect representation of a sphere.

:To quote ''{{w|The Princess Bride}}'': "Yes, you're very smart. Shut up."

{{clear}}

;Waterman Butterfly
[[File:WatermanButterflyProjection.jpg|frame|The Waterman Butterfly projection]]
:Similar to the Dymaxion, the {{w|Waterman butterfly projection}} turns a sphere into an octahedron, and then unfolds the net of the octahedron, which was devised by mathematician {{w|Waterman polyhedron|Steve Waterman}} based upon the work of {{w|Bernard J.S. Cahill}}

:Bernard Cahill published a [http://www.genekeyes.com/B.J.S._CAHILL_RESOURCE.html butterfly map] in 1909. Steve Waterman probably has the only extant "ready to go" map following the same general principles, though Gene Keys may not be far behind. Waterman has a poem with graphics in a similar vein to this xkcd comic that is worth reading.[http://watermanpolyhedron.com/worldmap.html]

:[http://www.progonos.com/furuti/MapProj/Normal/ProjPoly/projPoly2.html Polyhedral projections] like Cahill, Dymaxion or Waterman typically offer better accuracy of size, shape and area than flat projections, at the expense of compass directionality, connectedness, and other complications.

:The joke is that the person responding deeply understands map projections; anyone who knows of this projection is a person that Randall would like to get to know.

{{clear}}

;Peirce Quincuncial
[[File:PeirceQuincuncialProjection.jpg|frame|The Peirce Quincuncial projection]]
:The {{w|Pierce quincuncial projection}} was devised by {{w|Charles Sanders Peirce}} in 1879 and uses {{w|complex analysis}} to make a {{w|conformal mapping}} of the Earth, that conforms except for four points which would make up the south pole.

:{{w|Inception}} was a 2010 movie about {{w|meta}} {{w|lucid dream}}ing. It has a complex story that is difficult to follow and leaves the viewer with many questions at the end, and almost needs to be watched multiple times to be understood.

:The human brain is not well developed to deal with oddly obvious things. One example is that everyone has a skeleton, but everyone is surprised to see a part of their body represented by an X-Ray. Another is the fascinating complexity of the human hand, a machine which is amazingly complex, driven by a complex interplay of electrical and chemical signals; yet is the size of the hand and so useful.

{{clear}}

;Gall-Peters
[[File:Gall-PetersProjection.jpg|frame|The Gall-Peters projection]]
:The {{w|Gall-Peters projection}} is mired in controversy, surprising for a map. {{w|James Gall}} a 19th century clergyman presented this projection in 1855 before the {{w|British Association for the Advancement of Science}}. In 1967, the filmmaker {{w|Arno Peters}} created the same projection and presented it to the world as a "new invention" that put poorer, less powerful countries into their rightful proportions (as opposed to the Mercator). Peters played the marketing game and got quite a few followers of his map by saying it had "absolute angle conformality," "no extreme distortions of form," and was "totally distance-factual" in an age when society was very concerned about social justice. All of these claims were in fact false. The polar regions are horribly distorted, and south of the Mediterranean Sea is "taller" than it should be.

:Anyone who loves such a politically charged map that has become popular by way of marketing stunts, Randall would rather not have anything to do with.

{{clear}}

The title text makes a joke that goes to the familiar meme from ''{{w|CSI: Miami}}'', in which the star, David Caruso starts a sentence, then [[:Category:Puts on sunglasses|puts on his sunglasses]] and ends the sentence with a corny pun. In this case, the pun is on {{w|map projection}} and {{w|projection (psychology)|projection}} in Psychology. Psychologic projection is an immature defense mechanism wherein a person who is uncomfortable with their own thoughts and/or actions assumes that another also shares this thought or action and blames that person for thinking/behaving that way, removing some of the negative feelings they have towards themselves. The Sunglasses internet meme has been mentioned previously by xkcd in comics [[626]], [[524]] and possibly others.

==Transcript==
:What your favorite
:'''Map Projection'''
:says about you
:[All of these are organized as Title, a copy of the particular projection underneath, and what it says about you under that.]

:*Mercator
:**You're not really into maps.
:*Van der Grinten
:**You're not a complicated person. You love the Mercator projection; you just wish it weren't square. The Earth's not a square, it's a circle. You like circles. Today is gonna be a good day!
:*Robinson
:**You have a comfortable pair of running shoes that you wear everywhere. You like coffee and enjoy The Beatles. You think the Robinson is the best-looking projection, hands down.
:*Dymaxion
:**You like Isaac Asimov, XML, and shoes with toes. You think the Segway got a bad rap. You own 3D goggles, which you use to view rotating models of better 3D goggles. You type in Dvorak.
:*Winkel-Tripel
:**National Geographic adopted the Winkel-Tripel in 1998, but you've been a W-T fan since ''long'' before "Nat Geo" showed up. You're worried it's getting played out, and are thinking of switching to the Kavrayskiy. You once left a party in disgust when a guest showed up wearing shoes with toes. Your favorite musical genre is "Post–".
:*Goode Homolosine
:**They say mapping the Earth on a 2D surface is like flattening an orange peel, which seems enough to you. You like easy solutions.You think we wouldn't have so many problems if we'd just elect ''normal'' people to Congress instead of Politicians. You think airlines should just buy food from the restaurants near the gates and serve ''that'' on board. You change your car's oil, but secretly wonder if you really ''need'' to.
:*Hobo-Dyer
:**You want to avoid cultural imperialism, but you've heard bad things about Gall-Peters. You're conflict-averse and buy organic. You use a recently-invented set of gender-neutral pronouns and think that what the world needs is a revolution in consciousness.
:*Plate Carrée <small>(Equirectangular)</small>
:**You think this one is fine. You like how X and Y map to latitude and longitude. The other projections overcomplicate things. You want me to stop asking about maps so you can enjoy dinner.
:*A Globe!
:**Yes, you're very clever.
:*Waterman Butterfly
:**Really? You know the Waterman? Have you seen the 1909 Cahill Map it's based— ...You have a framed reproduction at home?! Whoa. ...Listen, forget these questions. Are you doing anything tonight?
:*Peirce Quincuncial
:**You think that when we look at a map, what we really see is ourselves. After you first saw ''Inception'', you sat silent in the theater for six hours. It freaks you out to realize that everyone around you has a skeleton inside them. You ''have'' really looked at your hands.
:*Gall-Peters
:**I ''hate'' you.

{{comic discussion}}
[[Category:Charts]]
[[Category:Maps‏‎]]
[[Category:Puts on sunglasses]]

977: Map Projections

2015-02-16T23:32:43Z

199.27.128.184: Dvorak being superior to Qwerty is mostly legend.

{{comic
| number = 977
| date = November 14, 2011
| title = Map Projections
| image = map_projections.png
| titletext = What's that? You think I don't like the Peters map because I'm uncomfortable with having my cultural assumptions challenged? Are you sure you're not... ::puts on sunglasses:: ...projecting?
}}

==Explanation==
{{w|Map projection}}, or how to represent the spherical Earth surface onto a flat support (paper, screen...) to have a usable map, is a long-time issue with very practical aspects (navigation, geographical shapes and masses visualization, etc.) as well as very scientific/mathematical ones, involving geometry or even abstract algebra among other things. There is no universal solution to this problem, any 2D map projection will always distort in a way the spherical reality; many projections have been proposed in various contexts, each intending to minimize distortions for specific uses (for nautical navigation, for aerial navigation, for landmass size comparisons, etc.) but having drawbacks from other points of view. Some of them are more frequently used than others in mass media and therefore more well-known than others, some are purely historical and now deprecated, some are very obscure, etc.

[[Randall]] suggests here the idea that someone's "favorite" map projection can reveal aspects of their personality, then goes through a series of them to show what they can mean:

;Mercator
[[File:MercatorProjection.jpg|frame|The Mercator projection]]
:The {{w|Mercator projection}} was introduced by Flemish cartographer Gerardus Mercator in 1569. The main purpose of this map is that at any point the vertical and horizontal scales are the same, so locally i.e. considering only a small part of the map, geographical features (shapes, angles) are well represented, which helps a lot in recognizing them on-the-field, or for local navigation in that small part only. For this reason, that projection (or a close variant) is used in several online mapping services, such as Google Maps, which means that it is frequently encountered by the general public. No angle distortion also means that a straight line on the map corresponds to a course of constant bearing (direction), which was very useful for nautical navigation in the past (and thus made that projection very well-known).

:However, from a global point of view, this projection is radically incorrect in how it shows the size of landmasses (for instance Antarctica or Greenland seem gigantic), and furthermore, it always excludes a small region around each pole (otherwise the map would be of infinite height), so it doesn't provide a complete solution for the problem of map projection. The comic implies that people who like that projection aren't very interested with map issues, and typically use what they are offered without thinking much about it.

{{clear}}

;Van der Grinten
[[File:VanDerGrintenProjection.jpg|frame|The Van der Grinten projection]]
:The {{w|Van der Grinten projection}} is not much better than the Mercator. It was adopted by {{w|National Geographic}} in 1922 and was used until they updated to the Robinson projection in 1988.

:The Van der Grinten projection is circular as opposed to the Mercator projection. Circles look happier than squares, leading to the conclusion that people who like the projection are optimistic.

{{clear}}

;Robinson
[[File:RobinsonProjection.jpg|frame|The Robinson projection]]
:The {{w|Robinson projection}} was developed by {{w|Arthur H. Robinson}} as a map that was supposed to look nice and is often used for classroom maps. National Geographic switched to this projection in 1988, and used it for ten years, switching to the Winkel-Tripel in 1998.

:{{w|The Beatles}} was a rock band that enjoyed great commercial success in the 1960s. The Beatles, coffee, and running shoes suggest an ordinary, easygoing lifestyle paralleled by the projection.

{{clear}}

;Dymaxion
[[File:DymaxionProjection.jpg|frame|The Dymaxion projection]]
:Also called the Fuller Map, the {{w|Dymaxion Map}} takes a sphere and projects it onto an icosahedron, that is a polyhedron with 20 triangular faces. It is far easier to unwrap an icosahedron than it is to unwrap a sphere into a 2D object and has very little skewing of the poles.

:Randall associates the projection to geek subculture and niche markets:
:*{{w|Isaac Asimov}} was an American science-fiction writer, that (as well as publishing many textbooks) is considered the father of the modern concept of robots. He invented the {{w|Three Laws of Robotics}}. He also worked on more than 500 books throughout his career.
:*{{w|XML}} is the eXtensible Markup Language. It is used to represent data in a format that machines can read and understand, as well as being human-readable. In practice, XML is cumbersome to read.
:*{{w|Vibram FiveFingers|Toed-Shoes}} are a [[1065: Shoes|favorite]] of Randall's to pick on. In society they are seen as a {{w|geek}} clothing item.
:*Brought to the world by {{w|Dean Kamen}}, the {{w|Segway PT}} was supposed to be a device that changed the way cities were built. In reality, most principalities have put in place rules specifically against Segways, making them a frustration to own and use within the law (in some states in Australia, it is illegal to use them on public footpaths or roads). Also, the former owner of {{w|Segway Inc.}}, the late {{w|Jimi Heselden}}, accidentally rode his Segway off a cliff in 2010.
:*{{w|Virtual reality|3D goggles}} are a very niche market only pursued by enthusiasts. In the 1990s the promise of virtual realities was very tantalizing; many companies attempted to perfect it, but fell short of the mark. Also, the phrase "The grass is always greener on the other side of the fence" is relevant.
:*{{w|Dvorak Simplified Keyboard|Dvorak}} is an alternate keyboard layout to QWERTY. According to legend, QWERTY was invented to help keep manual typewriters from jamming (by placing the most used keys far from each other) but Dr. {{w|August Dvorak}} performed many studies and found the mathematically optimal keyboard layout to reduce finger travel for right handed typists. While some claim Dvorka is technically better than QWERTY, QWERTY had become the standard. All the keyboards were laid out in QWERTY format, and retraining the brain after becoming a touch typist is extremely difficult.

{{clear}}

;Winkel-Tripel
[[File:Winkel-TripelProjection.jpg|frame|The Winkel Tripel projection]]
:Proposed by {{w|Oswald Winkel}} in 1921, this map tried to reduce a set of three (German: Tripel) main problems with map projections: area, direction, and distance. The {{w|Kavrayskiy VII projection|Kavrayskiy projection}} is very similar to the Winkel Tripel and was used by the USSR, but very few in the Western world know of it.

:The comic links this projection to {{w|hipster}} subculture. The hipster stereotype is to avoid conforming to mainstream fashions. "Post-" refers to a variety of musical genres such as {{w|post-punk}}, {{w|post-grunge}}, {{w|post-minimalism}}, etc. that branch off of other genres.

{{clear}}

;Goode Homolosine
[[File:GoodeHomolosineProjection.jpg|frame|The Goode Homolosine projection]]
:The {{w|Goode homolosine projection}} takes a different approach to skewing a sphere into a roughly circular surface. An orange peel can be taken from an orange and flattened with fair success; this is roughly the procedure that {{w|John Paule Goode}} followed in creating this projection. Randall is suggesting that people who like this map also prefer relatively easy solutions to other things in life, despite those solutions having nuanced problems that are more difficult to address.

:Common people make arguments that if normal people would run the United States, then the US wouldn't be in the trouble it is. This is from the belief that career politicians are simply out to make money and will only act in the interest of their constituency when their continued easy life is threatened (usually around election time).

:Airline food is another, much maligned, problem. How do you store enough food to feed people on long airplane trips? The common solution is to use some kind of sub-standard microwaveable dinner. Randall is saying that the people in favor of the Goode Homolosine wonder why the airlines don't simply order meals from the restaurants in the airport, store that food, and serve it, rather than using frozen and microwaved food.

:Older cars burned oil like mad fiends, and oil back then would become corrosive to the innards of an engine, so oil had to be changed often. But, with the introduction of synthetic motor oil and better designed engines, new cars only need their oil changed about every 10,000 to 15,000 miles. A common conspiracy theory is that modern automobile oil manufacturers still recommend that car owners change their oil every 3,000-5,000 miles to "drum" up more business, even though that frequency is unnecessary.

:All of these references suggest that people who like the Goode Homolosine projection are fans of easy solutions to problems. However, the solutions would not necessarily work in practice. For instance, the restaurants might have trouble making enough food for the whole plane, and it could get cold before being served. Also, the air conditions [http://www.nbcnews.com/health/one-reason-airline-food-so-bad-your-own-tastebuds-6C10823522 aboard planes] can affect taste, so airlines say they optimize for this. And there is no such thing as a "normal" person, and if there were, he/she would have virtually no chance at actually getting into government office.

{{clear}}

;Hobo-Dyer
[[File:Hobo-DyerProjection.jpg|frame|The Hobo-Dyer projection]]
:The {{w|Hobo–Dyer projection}} was commissioned by Bob Abramms and Howard Bronstein and was drafted by Mick Dyer in 2002. It is a modified {{w|Behrmann projection}}. The goal was to be a more visually pleasing version of the Gall-Peters.

:As is discussed in the Gall-Peters explanation, the Gall-Peters was developed to be equal area, so that economically disadvantaged areas can at least take comfort in the fact that their country is represented correctly by area on maps.

:Randall associates the Hobo-Dyer projection to "crunchy granola" — a stereotype associated with vegetarianism, environmental activism, anti-war activism, liberal political leanings, and some traces of {{w|hippie}} culture.

:With the new general acceptance of homosexual, bisexual, and transgender persons, some have begun to invent gender-neutral pronouns so that when referring to a person whose gender is not known they cannot be offended by being referred to by the wrong pronouns. In {{w|Middle English}} 'they' and 'their' were accepted gender-less pronouns that could replace 'he', 'she' as well as be used to represent a crowd, but this usage is considered by some to be grammatically incorrect because of the plural/singular debate ([http://www.merriam-webster.com/video/0033-hisher.htm stupid Victorian Grammarians!]). None of the {{w|gender-neutral pronoun#Invented_pronouns|many attempts at popularizing gender-neutral pronouns}} have achieved any degree of success in the mainstream.

:Randall seems to associate the Hobo-Dyer projection with the Social Justice movements on social media sites such as Tumblr.

{{clear}}

;Plate Carrée
[[File:PlateCarreeProjection.jpg|frame|The Plate Carrée projection]]
:Also known as the {{w|Equirectangular projection}} has been in use since, apparently, 100 AD. The benefit of this projection is that latitude and longitude can be used as x,y coordinates. This makes it especially easy for computers to graph data on top of it.

:According to the comic, the projection appeals to people who find much beauty in simplicity.

{{clear}}

;A Globe!
[[File:GlobeProjection.jpg|frame|The Globe "projection"]]
:In any good discussion there has to be at least one smart-ass. This is a comic about map projections, that is, the science of taking a sphere and flattening it into 2 dimensions. The smart-ass believes that we shouldn't even try: a sphere is, tautologically, the perfect representation of a sphere.

:To quote ''{{w|The Princess Bride}}'': "Yes, you're very smart. Shut up."

{{clear}}

;Waterman Butterfly
[[File:WatermanButterflyProjection.jpg|frame|The Waterman Butterfly projection]]
:Similar to the Dymaxion, the {{w|Waterman butterfly projection}} turns a sphere into an octahedron, and then unfolds the net of the octahedron, which was devised by mathematician {{w|Waterman polyhedron|Steve Waterman}} based upon the work of {{w|Bernard J.S. Cahill}}

:Bernard Cahill published a [http://www.genekeyes.com/B.J.S._CAHILL_RESOURCE.html butterfly map] in 1909. Steve Waterman probably has the only extant "ready to go" map following the same general principles, though Gene Keys may not be far behind. Waterman has a poem with graphics in a similar vein to this xkcd comic that is worth reading.[http://watermanpolyhedron.com/worldmap.html]

:[http://www.progonos.com/furuti/MapProj/Normal/ProjPoly/projPoly2.html Polyhedral projections] like Cahill, Dymaxion or Waterman typically offer better accuracy of size, shape and area than flat projections, at the expense of compass directionality, connectedness, and other complications.

:The joke is that the person responding deeply understands map projections; anyone who knows of this projection is a person that Randall would like to get to know.

{{clear}}

;Peirce Quincuncial
[[File:PeirceQuincuncialProjection.jpg|frame|The Peirce Quincuncial projection]]
:The {{w|Pierce quincuncial projection}} was devised by {{w|Charles Sanders Peirce}} in 1879 and uses {{w|complex analysis}} to make a {{w|conformal mapping}} of the Earth, that conforms except for four points which would make up the south pole.

:{{w|Inception}} was a 2010 movie about {{w|meta}} {{w|lucid dream}}ing. It has a complex story that is difficult to follow and leaves the viewer with many questions at the end, and almost needs to be watched multiple times to be understood.

:The human brain is not well developed to deal with oddly obvious things. One example is that everyone has a skeleton, but everyone is surprised to see a part of their body represented by an X-Ray. Another is the fascinating complexity of the human hand, a machine which is amazingly complex, driven by a complex interplay of electrical and chemical signals; yet is the size of the hand and so useful.

{{clear}}

;Gall-Peters
[[File:Gall-PetersProjection.jpg|frame|The Gall-Peters projection]]
:The {{w|Gall-Peters projection}} is mired in controversy, surprising for a map. {{w|James Gall}} a 19th century clergyman presented this projection in 1855 before the {{w|British Association for the Advancement of Science}}. In 1967, the filmmaker {{w|Arno Peters}} created the same projection and presented it to the world as a "new invention" that put poorer, less powerful countries into their rightful proportions (as opposed to the Mercator). Peters played the marketing game and got quite a few followers of his map by saying it had "absolute angle conformality," "no extreme distortions of form," and was "totally distance-factual" in an age when society was very concerned about social justice. All of these claims were in fact false. The polar regions are horribly distorted, and south of the Mediterranean Sea is "taller" than it should be.

:Anyone who loves such a politically charged map that has become popular by way of marketing stunts, Randall would rather not have anything to do with.

{{clear}}

The title text makes a joke that goes to the familiar meme from ''{{w|CSI: Miami}}'', in which the star, David Caruso starts a sentence, then [[:Category:Puts on sunglasses|puts on his sunglasses]] and ends the sentence with a corny pun. In this case, the pun is on {{w|map projection}} and {{w|projection (psychology)|projection}} in Psychology. Psychologic projection is an immature defense mechanism wherein a person who is uncomfortable with their own thoughts and/or actions assumes that another also shares this thought or action and blames that person for thinking/behaving that way, removing some of the negative feelings they have towards themselves. The Sunglasses internet meme has been mentioned previously by xkcd in comics [[626]], [[524]] and possibly others.

==Transcript==
:What your favorite
:'''Map Projection'''
:says about you
:[All of these are organized as Title, a copy of the particular projection underneath, and what it says about you under that.]

:*Mercator
:**You're not really into maps.
:*Van der Grinten
:**You're not a complicated person. You love the Mercator projection; you just wish it weren't square. The Earth's not a square, it's a circle. You like circles. Today is gonna be a good day!
:*Robinson
:**You have a comfortable pair of running shoes that you wear everywhere. You like coffee and enjoy The Beatles. You think the Robinson is the best-looking projection, hands down.
:*Dymaxion
:**You like Isaac Asimov, XML, and shoes with toes. You think the Segway got a bad rap. You own 3D goggles, which you use to view rotating models of better 3D goggles. You type in Dvorak.
:*Winkel-Tripel
:**National Geographic adopted the Winkel-Tripel in 1998, but you've been a W-T fan since ''long'' before "Nat Geo" showed up. You're worried it's getting played out, and are thinking of switching to the Kavrayskiy. You once left a party in disgust when a guest showed up wearing shoes with toes. Your favorite musical genre is "Post–".
:*Goode Homolosine
:**They say mapping the Earth on a 2D surface is like flattening an orange peel, which seems enough to you. You like easy solutions.You think we wouldn't have so many problems if we'd just elect ''normal'' people to Congress instead of Politicians. You think airlines should just buy food from the restaurants near the gates and serve ''that'' on board. You change your car's oil, but secretly wonder if you really ''need'' to.
:*Hobo-Dyer
:**You want to avoid cultural imperialism, but you've heard bad things about Gall-Peters. You're conflict-averse and buy organic. You use a recently-invented set of gender-neutral pronouns and think that what the world needs is a revolution in consciousness.
:*Plate Carrée <small>(Equirectangular)</small>
:**You think this one is fine. You like how X and Y map to latitude and longitude. The other projections overcomplicate things. You want me to stop asking about maps so you can enjoy dinner.
:*A Globe!
:**Yes, you're very clever.
:*Waterman Butterfly
:**Really? You know the Waterman? Have you seen the 1909 Cahill Map it's based— ...You have a framed reproduction at home?! Whoa. ...Listen, forget these questions. Are you doing anything tonight?
:*Peirce Quincuncial
:**You think that when we look at a map, what we really see is ourselves. After you first saw ''Inception'', you sat silent in the theater for six hours. It freaks you out to realize that everyone around you has a skeleton inside them. You ''have'' really looked at your hands.
:*Gall-Peters
:**I ''hate'' you.

{{comic discussion}}
[[Category:Charts]]
[[Category:Maps‏‎]]
[[Category:Puts on sunglasses]]

184: Matrix Transform

2014-11-21T00:36:12Z

199.27.128.184: /* Explanation */ added a bit more details of an explanation; moved comment about translation/scaling into body; added clockwise speculation

{{comic
| number = 184
| date = November 15, 2006
| title = Matrix Transform
| image = matrix_transform.png
| titletext = In fact, draw all your rotational matrices sideways. Your professors will love it! And then they'll go home and shrink.
}}

==Explanation==
A {{w|Rotation matrix|rotational matrix transformation}} (i.e. the big brackets with a few "cos" and "sin" in them) is used in computer graphics to rotate an image. In general, to rotate a point [a1, a2] in a 2D space by z° clockwise, you can multiply it by the rotation matrix [cos z°, sin z°; -sin z°, cos z°]. In this case, the left side of the equation is rotating [a1, a2] by 90°. Simplifying the trigonometry, the 90° clockwise rotation matrix is [ 0, 1; -1, 0], so multiplying this by [a1, a2], you should get [a2, -a1].

The joke is that the author performed the rotation transformation on the image of the vector rather than just the vector itself.

Rotational matrix transformations are a special case of the general linear matrix transform, which can do other things to images, including the other two affine transformations of scaling them or translating (moving) them. On a pedantic note, normally mathematics uses counterclockwise as a default, although computer graphics frequently use a clockwise default, so this may be an intentional reference.

So the title text may be referring to the professors going home (translation) and shrinking (scaling) from the joke.

==Transcript==
:[A square matrix next to a vertical two-by-one matrix, equated to a horizontal matrix that looks like the two-by-one matrix turned 90 degrees.]
:[Square matrix:
: cos90° sin90°
: -sin90° cos90°]
:[Two by one matrix:
: a₁
: a₂]
:[An equal sign]
:[The same two by one matrix, but rotated by 90 degrees clockwise:
: a₁
: a₂]

{{comic discussion}}
[[Category:Math]]