World Maps and Posters

Per the subject, I'm seeking some advice.

Fact: Spherical worlds presented on 2-D maps should generally be twice as wide as high, e.g., a 30" poster should be 15" high. Of course, they're not if Google Images searches on the Forgotten Realms, Pathfinder, Eberron, and other RPG settings are the reality - they're usually 30" wide by 24" high.

Well, I'm in the midst of creating my first world map for the commercial game system I've been working on since 2007. Should I go with the flow of 30x24, or set the map up to be "realistic" at 2x width, 1x height? Your thoughts are genuinely appreciated.

Chuck

i'd stick with a more classical style so prob 30 x 24. keep in mind the 2 x 1 ratio is something used in real-world maps and projections and the fantasy ones you mentioned are generally more artistic and rarely have anything like graticules on them so you can afford to be more lax. at least thats a laypersons opinion :)

You have to think in terms of US printing standards first, I think. I you want some commercial release, try not to be stuck in really custom sizes because it could increase the printing costs.

Example of ANSI sizes

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Originally Posted by heffnerc1

Fact: Spherical worlds presented on 2-D maps should generally be twice as wide as high, e.g., a 30" poster should be 15" high.

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No, this is wrong.

There are a number of projections which map the surface of a sphere onto a shape with a 2:1 aspect ratio, but none of them is generally used for general reference maps like the typical wall map.

Tangent Equidistant Cylindrical gives a 2:1 rectangle, and is very simple, but also very ugly and it distorts both shape and area dramatically. It has some specialized uses but is not appropriate for a reference maps, particularly those involving density.

Mollweide and Hammer both map onto 2:1 ellipses, and both preserve areas. But as shape is generally more significant for reference maps, they aren't used much for wall maps. They are very good for thematic maps particularly those involving density.

Sinusoidal Is an equal area psuedocylindrical projection much like Mollweide, but the shape it forms is different, the area between two mirrored "humps" from a sine wave. It is 2:1, but its not often used for reference maps for the same reasons as Mollweide.

A pair of azimuthal projections of opposite hemispheres side by side has a 2:1 ratio (its two circles) and they have been used for reference maps, but they usually have additional components such as polar insets, titles, and other bits that reduce the aspect ratio significantly.

That doesn't mean you can just do whatever you want and have it work out, regardless of what aspect ratio or shape you use. If you want your world to really work (say you want to be able to display it on a sphere in 3D, or you want to be able to figure out proper spherical distance) you need to understand at least the rudiments of projections and spherical geometry. If you don't care about that and are happy with a world that is effectively flat or cylindrical (Or if it really is flat or cylindrical) then just do whatever looks good.

A believe that the typical equirectangular projection is 2:1. Equirectangular is also convenient for turning into an orthographic projection, so I like it despite its distortions. The map I am doing is built as 36x18, with a 6 inch space at the bottom for whatever I want to put there. This takes the map to 36x24 which is a good poster size. I am a few days from being ready for the first test print on poster sized format.

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Originally Posted by vorropohaiah

i'd stick with a more classical style so prob 30 x 24. keep in mind the 2 x 1 ratio is something used in real-world maps and projections and the fantasy ones you mentioned are generally more artistic and rarely have anything like graticules on them so you can afford to be more lax. at least thats a laypersons opinion :)

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Originally Posted by Depassage

You have to think in terms of US printing standards first, I think. I you want some commercial release, try not to be stuck in really custom sizes because it could increase the printing costs.
Example of ANSI sizes

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Agree with you both since realism won't mean a lot if its printing price increases by 50-200% due to a non-standard printing size.

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Originally Posted by Hai-Etlik

(condensed) No, this is wrong. There are a number of projections which map the surface of a sphere onto a shape with a 2:1 aspect ratio, but none of them is generally used for general reference maps like the typical wall map.

(snip)

That doesn't mean you can just do whatever you want and have it work out, regardless of what aspect ratio or shape you use. If you want your world to really work (say you want to be able to display it on a sphere in 3D, or you want to be able to figure out proper spherical distance) you need to understand at least the rudiments of projections and spherical geometry.

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To be honest, I'd rather not reinvent the wheel, and asked in part to see what options were available that work within a printed medium. You've cited several 2:1 map examples, but if you were printing the map on a 2D surface, which one would you recommend as the most realistic for determining the distance between two points?

Thank you for your help,
Chuck

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Originally Posted by Veldehar

A believe that the typical equirectangular projection is 2:1. Equirectangular is also convenient for turning into an orthographic projection, so I like it despite its distortions. The map I am doing is built as 36x18, with a 6 inch space at the bottom for whatever I want to put there. This takes the map to 36x24 which is a good poster size. I am a few days from being ready for the first test print on poster sized format.

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Thanks for the input, it's much appreciated. One question - as you're designing your world, are you doing it at 72dpi, 100dpi, or 300dpi? Again, thank you.

If you want to print most use the 300ppi.

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Originally Posted by heffnerc1

To be honest, I'd rather not reinvent the wheel, and asked in part to see what options were available that work within a printed medium. You've cited several 2:1 map examples, but if you were printing the map on a 2D surface, which one would you recommend as the most realistic for determining the distance between two points?

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No projection can do that for an entire globe. Distance will always be distorted. You can preserve one of: distance through a fixed point (or its antipode), area, or angles. Or you can approximately preserve area, angles, and all distances within some restricted extent; the smaller the extent, the better the approximation.

If you just want a typical wall reference map, modern hybrid projections like Winkel Tripel and Robinson are used for a reason. They don't preserve anything precisely, but they do give a good overview. If you want something a bit more archaic looking, you could try Mercator or a hemisphere map, probably in Stereographic. As I said earlier, the hemisphere map can fit in a 2:1 rectangle, or a lower aspect ratio that would look nicer and fit typical paper better if you add polar insets. The others all have lower aspect ratios, and likewise can be adjusted with insets titles and other bits.

Poster size things are often printed at less than 300 dpi. If you don't expect the user to get as close to the poster as he would to a magazine he was reading 300dpi may be unnecessary, though not necessarily a bad idea, if you can afford the cost, and deal with the file size.