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> "AuthaGraph... faithfully represents all oceans and continents" What does this mean? Literally, that is impossible, so what's it actually preserving and dist
by GavinMcG 10y ago
> "AuthaGraph... faithfully represents all oceans and continents"
What does this mean? Literally, that is impossible, so what's it actually preserving and distorting?
It looks like angle is distorted. Is that it?
- ryandrake 10y agoIt looks like this is just another "equal area" projection. Many of these exist. Map projections are design to minimize certain distortions but at the expense of additional other distortions. Obviously since the world is round, you cannot minimize all of them. Other examples of distortions that a projection can aim to minimize are: distance, direction, scale, angle. An example of another existing equal area projection is the Mollweide projection: [1] which you may have seen before. 1: https://en.wikipedia.org/wiki/Mollweide_projection https://en.wikipedia.org/wiki/Mollweide_projection
- kuschku 10y agoCorrect, but this is one that has two important properties: It tiles, so it can be used for web maps, and you only need to rotate it to always have it point north, so it can be used for mobile maps. Google Maps, and similar tile systems, can’t have the local area undistorted and pointed in the right direction without these properties – and this map fulfills them.
- anderskaseorg 10y agoThe AuthaGraph map is an equal area map, not a conformal map, so its local maps are distorted. For example, you can see that the meridians and parallels fail to meet at right angles. The similar Lee Conformal Tetrahedric projection (http://www.csiss.org/map-projections/Miscellaneous/Lee_Conformal_Tetrahedric.pdf http://www.csiss.org/map-projections/Miscellaneous/Lee_Confo...) has undistorted local maps, at the expense of somewhat large area differences for different regions (though perhaps not as bad as Mercator).
- al452 10y agoFor one thing there is massive distortion of relative distances in southern parts... New Zealand or Australia to Antarctica is something like 4 hours flight, not halfway across the planet.
- GavinMcG 10y agoNot once you tesselate the maps
- hyperion2010 10y agoExcept for the fact that it tessellates so all you need to do is make the map a bit bigger and that distortion goes away (seen in [0]). 0. http://www.spoon-tamago.com/wp-content/uploads/2016/10/authagraph-world-map-2.jpg http://www.spoon-tamago.com/wp-content/uploads/2016/10/autha...
- Semiapies 10y agoA map shouldn't need an infinite series of other maps to be useful.
- hexane360 10y agoBut if you have an infinite series of maps (e.g. google maps) then using a projection that takes advantage of that is indeed useful.
- klodolph 10y agoYou're looking for a map where a straightish line gives you the direct path between two points? That's completely impossible. Flying from LA to Tokyo will take you over Alaska. Try to work that one out on a map. (Yeah, you can make a map where straight lines work, but only for a chosen point of origin or antipodes around that point.)
- jpatokal 10y agoThen why are you labeling it "completely impossible"? Here's a perfectly sensible straightish-line path between LAX and NRT, using a polar-aspect orthographic projection: http://www.gcmap.com/mapui?P=LAX-NRT&MS=wls&MP=p&DU=mi http://www.gcmap.com/mapui?P=LAX-NRT&MS=wls&MP=p&DU=mi