This discussion centers on map projections, sparked by an XKCD comic and its various interpretations and elaborations. The primary themes explored are the impact of map projections on perception, the technical merits and aesthetic considerations of different projections, and the historical and geographical context of mapmaking.
The Influence of Map Projections on Perception
A significant portion of the conversation revolves around how different map projections can alter our understanding of geographical areas and, by extension, the perceived importance of nations and regions. The Mercator projection, in particular, is frequently cited for its distortion of landmass sizes, leading to misperceptions that can influence historical and ongoing geopolitical views.
- The idea that we judge a country's importance by its size on a Mercator projection is questioned. As one user states, "I have always found it a bizarre idea that we allegedly judge a country's importance by it's size on a Mercator projection map. Does anyone really think Greenland is the most important place in the world?" (rich_sasha)
- The impact of Mercator on childhood perceptions is also highlighted: "In my childhood I definitely thought Greenland was a much physically large place than it is, because of the mercator world map the hung on the wall in home room. Was dumbfounded when I learned it actually fits within the continental US." (varenc)
- Another user connects the projection's distortion to historical exploitation: "Also notable that in the centuries following Mercator projection, Africa, the Indian subcontinent and the northern parts of South America actually shrunk by the map were regarded as vast, unexplored wildernesses full of resources to plunder (and the northern realms expanded by the projection as inaccessible icy wasteland)." (notahacker)
- Some users find value in alternative projections for making the familiar look new: "As a European the "Oceania - South at Top" looks like some other planet. I like this very much - that there are ways of looking at something so singular and familiar, our shared planet, that make it look new and unfamiliar." (andyjohnson0)
Technical Merits and Aesthetic Preferences of Map Projections
The discussion delves into the technical specifications and visual appeal of various map projections, particularly contrasting the Gall-Peters projection with newer alternatives like the Equal Earth projection. Debates arise over what constitutes an "improvement" or a "better" projection, with equal-area properties and visual harmony being key points of consideration.
- The rationale behind the "Equal Earth Projection" is explained, emphasizing its visually pleasing nature and equal-area properties as an alternative to the Gall-Peters. "It was created to provide a visually pleasing alternative to the Gall-Peters projection, which some schools and socially concerned groups have adopted out of concern for fairness. Their priority is to show developing countries in the tropics and developed countries in the north with correctly proportioned sizes." (PaulRobinson, quoting the Equal Earth description)
- The aesthetic appeal of Gall-Peters is directly challenged: "Usually it all boils down to "aesthetics". I am pretty sure most would agree that Gall-Peters is atrocious looking!" (orangeboats)
- Questions are raised about the unique selling points of new projections compared to existing ones: "Yes, and there are also already multiple equal-area projections with similar properties, too. For example, the Goode homolosine 'orange-peel' projection only loses out by failing to show contiguous oceans (emphasizing land masses instead) and having a discontinuity where two simpler projections are joined." (zahlman)
- Technical constraints and design goals are discussed, such as the desire for curved sides to suggest a sphere and straight parallels for ease of comparison, leading to the classification as pseudocylindrical: "Okay, we've now added a constraint that this should be pseudocylindrical." (vitus)
- The computational ease of polynomial equations versus elliptical arcs is noted as an advantage for the Equal Earth projection: "The equal earth projection is computationally easier to translate between lat/long and map coordinates, as it explicitly uses a polynomial equation instead of strict elliptical arcs." (vitus)
- Aptitude for visualizing map projections is offered: "I found https://map-projections.net/singleview.php which you can view a bunch of other possible candidates by selecting Pseudocylindric + Equal-Area." (vitus)
Geographical Context and Cartographic Conventions
This theme covers the historical and practical reasons behind certain cartographic choices, such as the placement of the Greenwich meridian and the International Date Line, as well as the selection of place names and geographical features on maps.
- The orientation of maps and its relation to natural phenomena like the sun and clocks is discussed: "Living in the northern hemisphere, it bugs me that standard north-up, west-left maps don't match up with the sun and with our clocks. It's neat that both clock hands and the sun are 'up' at noon. It would be even neater if that upward direction corresponded to south, since that's where the sun actually is at midday." (supersrdjan)
- The seemingly arbitrary placement of the Greenwich meridian is debated, with a pragmatic explanation following: "As I understand it, it's not the best location, it's just good enough and was very popular for historical reasons." (MrJohz)
- The convenience of the Greenwich meridian's placement relative to the International Date Line is highlighted: "I don't think enough people talk about how lucky we are that the International Date Line can roughly follow a line of longitude 180 degrees from the Greenwich meridian. If you were on a planet with more land, or we could only draw it through the Atlantic or Australia, timezones would be a lot weirder." (mapmeld)
- Specific inaccuracies on a map are pointed out, influencing user confidence: "The name of the island I live on (Amami) is misspelled. That does not give me a great deal of confidence about the rest of the map." (francisdavey)
- A subtle distinction in political geography is raised regarding the status of British Crown dependencies: "Small quibble: the Isle of Man, Guernsey and Jersey all have '(UK)' appended. They are not actually part of the UK, but British Crown dependencies. Possible confusion (as with most things British and overseas)." (kitd)
- The selection of cities and geographical features on maps is also noted as potentially eccentric: "The choices of cities, towns, and lakes to display in New Zealand is rather strange. The biggest lakes in the South Island are missing, and Napier, Rotorua, and Nelson are shown while some bigger places aren't." (mkl)
- The idea that "it's not the size of the landmass that counts ... It's how you use it" presents an alternative perspective on geographical value. (frithsun)
- A useful tool for comparing actual country sizes is recommended: "There's a great online tool to compare the actual sizes of countries https://www.thetruesize.com" (mentalgear)