1784: Bad Map Projection: Liquid Resize
|Bad Map Projection: Liquid Resize|
Title text: This map preserves the shapes of Tissot's indicatrices pretty well, as long as you draw them in before running the resize.
There is no perfect way to draw a map of the world on a flat piece of paper. Each one will introduce a different type of distortion, and the best projection for a given situation is sometimes very disputed. Randall previously explored 12 different projections in 977: Map Projections, and expressed his disdain for some types he sees as less efficient but whose users feel superior. None of them are really good as any 2D map projection will always distort in a way the spherical reality, and a map projection that is useful for one aspect (like navigation, geographical shapes and masses visualization, etc.) will not be so for all the others. Local maps of smaller areas can be quite accurate, but the idea of both these map projection comics is to map the entire globe on a flat surface.
This comic suggests that there are many other projections than the 12 from the previous map projection comic, and Randall seems to have an entire list, of which at least 107 are Bad Map Projections." The one presented here is #107 and is it called the "Liquid Resize." It is unclear if he includes the previous 12 in this list. Quite possibly he does, since all 2D projections of the surface of a 3D sphere will be bad in certain respects.
The Liquid Resize map projection, however, is not only useless for most map applications -- as the size, shape, and position of most countries are quite distorted -- but it's creation includes two steps which are outright counterproductive. If the list is sorted from best to worst it may be hard to find a worse projection method than this, so finding 106 projections better than this one seems realistic!
First, this method needs a planar map projection as its starting point, thus compounding the problems right off the bat. Planar projections are relatively accurate near the center but heavily distorted toward the edges. A famous example of a planar projection is the logo of the United Nations. Planar projections are just about useful for 3D graphics rendering, if the user needs a quick, inexpensive way to store map textures that will later be attached to a sphere.
Second, the map uses Photoshop's content aware resizing tool, a very questionable choice. (Using a Photoshop tool for a task it is not intended for was also used in 1685: Patch where a GNU patch tool was replaced with Adobe Photoshop's patch tool to compile code.) The content aware resizing tool resizes images by identifying what it thinks are important details and preserving these, while shrinking or stretching less detailed areas. For example, when used on a face, the algorithm detects that the eyes and mouth are important details and tries to keep these in place, while stretching the skin around it. When applied to a map, this means that areas with lots of countries - and therefore lots of detail - such as Europe, West Africa, the Eastern Mediterranean and Central America/the Caribbean are relatively unchanged, while big countries like India, China and the US are very warped. The choices that the resizing tool makes are also dependent on the exact visual features of the original map, such as the choice of not having any topography or infrastructure drawn on, or not including a latitude/longitude grid, so what areas are deemed as unimportant is even more arbitrary than it would be on, say, a photographic picture of the Earth.
Bad content aware scaling is already a meme. This projection does do a good job, however, of making almost every country clearly visible and indicating which countries are neighbors. South America fits into Africa almost as it did in the era of the super-continent Pangaea.
Tissot's indicatrices are equally sized small circles overlaid on a globe to show the distortion of a particular map projection; if the map distortion distorts the shapes or areas of countries, it will do the same to the circles. The title text suggests that the shapes of Tissot's indicatrices would be pretty well preserved by the Liquid Resize transformation, 'as long as you draw them in before running the resize'. This is a joke. "Drawing them in before running the resize" means that a different projection would be generated (probably preserving the indicatrices themselves), making the use of the indicatrices meaningless, sort of like cheating. In fact by drawing them small enough there will be no resizing at all.
- [Caption at the top of the panel:]
- Bad map projection #107:
- The Liquid Resize
- A political map compressed using Photoshop's content-aware resizing algorithm to cut down on unused blank space
- [Below the caption there is a map of the world divided and colored by political boundaries, with outlines around each continent in black and around each country in dark gray. Antarctica is colored in light gray, bodies of water in white, and countries in pale shades of red, orange, yellow, green, blue, and purple. The map is heavily distorted, with Africa in the center and the other continents curving around it, approximating the bounds of a square with rounded corners. The oceans have been removed but also huge countries like the US, Australia, Brazil, Russia and especially India and Argentina have been heavily distorted while areas in the center with many smaller countries like Africa and Europe is almost unchanged.]
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