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heffnerc1
06-21-2012, 05:14 AM
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

vorropohaiah
06-21-2012, 05:30 AM
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 :)

Depassage
06-21-2012, 06:08 AM
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 (http://en.wikipedia.org/wiki/Paper_size#ANSI_paper_sizes)

Hai-Etlik
06-21-2012, 07:00 AM
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.

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.

Veldehar
06-21-2012, 11:58 AM
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.

heffnerc1
06-21-2012, 03:18 PM
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 (http://en.wikipedia.org/wiki/Paper_size#ANSI_paper_sizes)

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.


(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.

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

heffnerc1
06-21-2012, 03:25 PM
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.

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.

Jaxilon
06-21-2012, 03:57 PM
If you want to print most use the 300ppi.

Hai-Etlik
06-21-2012, 06:32 PM
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?

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.

jwbjerk
06-21-2012, 10:27 PM
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.

Poison
06-22-2012, 10:09 AM
I think a Mercator should come close to the dimensions you need? It distorts pretty badly towards the poles, but unless you have anything significant going on there it shouldn't matter too much.
Alternatively, you could use a 2x1 (or other non-30x24) type map, but fill the remaining space with decorative or informative graphics. A lot of antique maps do this, see for instance here (http://www.smh.com.au/ffximage/2006/09/20/knMAPS_main,0.jpg) and here (http://imgc.allpostersimages.com/images/P-473-488-90/16/1602/YF2FD00Z/posters/petro-plancio-antique-map-terre-universelle-1594.jpg). It might help add some flavour, and solve the problem of the dimensions. Two birds, one stone?

Gidde
06-22-2012, 12:39 PM
I've been struggling with the same issue, since a watercolor sheet is 22x 30. I particularly like Mercator for both the aspect issue and the particular qualities of the projection (preserves shape) since I love nautical chart-type maps and that's Mercator's great strength. Its big weakness is scale distortion, so if you can handle that it's really great for "looking pretty" -- especially for a fantasy-histprical map since the truly realistic projections (ie the winkle triple that natgeo uses) end up looking too modern.


Sent from my iPhone using Tapatalk

Veldehar
06-22-2012, 03:28 PM
I'm doing my map at 300 DPI.

heffnerc1
06-23-2012, 03:49 AM
(condensed)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.


I think a Mercator should come close to the dimensions you need? It distorts pretty badly towards the poles, but unless you have anything significant going on there it shouldn't matter too much.
Alternatively, you could use a 2x1 (or other non-30x24) type map, but fill the remaining space with decorative or informative graphics. A lot of antique maps do this, see for instance here (http://www.smh.com.au/ffximage/2006/09/20/knMAPS_main,0.jpg) and here (http://imgc.allpostersimages.com/images/P-473-488-90/16/1602/YF2FD00Z/posters/petro-plancio-antique-map-terre-universelle-1594.jpg). It might help add some flavour, and solve the problem of the dimensions. Two birds, one stone?

Yes, agreed with both of you, and after checking out all the options, I'm going with a non-stereographic Mercator map at 36x18. Once I add 6" to the bottom for non-map data, it'll be print friendly at 36x24. Plus, it'll be "rhumb line" friendly: http://www.math.ubc.ca/~israel/m103/mercator/mercator.html Thank you very much for helping me learn more about the various map styles.


I'm doing my map at 300 DPI.

Thank you, I decided to go that route too since it's a lot easier to remove ppi than to add them. :-)

heffnerc1
06-23-2012, 04:00 AM
I've been struggling with the same issue, since a watercolor sheet is 22x 30. I particularly like Mercator for both the aspect issue and the particular qualities of the projection (preserves shape) since I love nautical chart-type maps and that's Mercator's great strength. Its big weakness is scale distortion, so if you can handle that it's really great for "looking pretty" -- especially for a fantasy-histprical map since the truly realistic projections (ie the winkle triple that natgeo uses) end up looking too modern.

Yep, especially about the Winkle Tripel maps - I checked them out for a few days but really liked the Mercator style maps a lot more. As for the watercolor sheets, they're also 30x22. Are you interested in creating something on them as an end result, or as a middle stage towards transposing them onto a 36x24 print?

Gidde
06-24-2012, 12:23 PM
The watercolor sheets are for their own maps; they'll be end results. And yeah, that should have been 30x22 ;)

HBrown
06-29-2012, 02:18 PM
It's simply not true that all map projections project a sphere to a 2x1 rectangle. Many do, it's true, particularly the pseudocylindrical projections. An equirectangular (plate caree) projection will do so as well, but many other cylindrical projections do not.

Someone mentioned the Mercator projection. To map the entire sphere using a Mercator projection you need a map that's infinitely tall. In the real world, you pick your cutoff latitudes, and that choice determines the proportions of your rectangle. No one seems to notice that the Mercator projection omits the poles, because in our world the poles are not overly significant in world events. How important are they in your world?

Azimuthal projections project to a circle. Many of these are incapable of projecting a whole sphere, and most are so distorted beyond a certain radius it's unprofitable to go there. That's how you end up with two circles side-by-side.

The height-to-width proportions of a cylindrical projection depend heavily on which standard parallel(s) you pick. Cylindrical projections are considered more suitable for regional maps than for global ones, but the choice depends on the region you're mapping and what you want to emphasize.

Do you need to map the whole world? The Mercator map that hung on the wall at my grade school omitted the poles but was considered good enough for its purposes. A map that omitted a swath of the Pacific Ocean might be appropriate for some purposes (but not if you're a Pacific Islander).

What is the tale you're trying to tell with your map? What parts of the world do you need for that tale? Is it more important to preserve shape, or proportional area, or compass direction (that's what the Mercator projection does). Pick the projection that best serves your purpose and let the proportions fall where they may.