If it's any help, my world climate map is here Planet Eben
The main reference I used for climate zones is here PCK: Climate maps and at Wikipedia.
A way to use Photoshop to correct the polar regions of an equirectangular map is here First swing at a map. Any suggestions/critiques are more than welcome (WIP)
A general visual guide to climate zone latitudes can be found in this thread Draesina: My First Attempt at Creating a Map :D
Last edited by ManOfSteel; 12-31-2012 at 04:08 AM.
jgibson is mostly correct but there are a couple of extra things.
Equirectangular is the term used more in the context of graphics. In cartography/geography, "Equidistant Cylindrical" is the more typical term for this projection. Both do describe the same thing, although in the case of geography it can be complicated when the surface being projected isn't a perfect sphere (which is way more detail than fictional map making needs).
Cylindrical projections are, as the name implies, based on a notional "cylinder" that you project the map onto and then "unroll" into the map. In the "normal aspect" the cylinder is aligned with the axis of the globe, although there are other aspects, you don't need to worry about them just now. So assuming a normal aspect, the cylinder can wrap snug around the globe at the equator, or it can be smaller and slice through the globe, in which case it intersects the surface at two parallels (latitude lines). In math speak we call these "tangent" (just touching) and "secant" (Cutting though). The parallels where the cylinder touches/cuts the globe are called the standard parallels, and they are were the map minimizes distortion. As you move away from them, distortion increases.
So, in the tangent case (the standard parallels are both the equator) The width of the map is the length of the equator, while the height of the map is the distance between the poles (North-south distances are preserved in this projection, hence the name "equdistant", other distances are distorted.) Assuming a perfect sphere, that makes the north-south distance falf the circumference, and the east-west distance the full circumference. So the aspect ratio is 2:1 as jgibson said. This particular case (normal tangent equidistant cylindrical) is also called "plate carree".
However, you can also set the standard parallels elsewhere, and get smaller aspect ratios. Again assuming a perfect sphere, you multiply the width by the cosine of the latitude. (If you know a bit of basic trigonometry, you can probably work out why this is the case fairly easily). If you don't know any trig, just use a scientific calculator enter the latitude, then press "cos". (On most calculators with trig functions at least. Fancier ones which allow you to enter multiple operations before executing generally want the "cos" before the latitude instead.)
If we assume your map is meant to be a full globe equidistant cylindrical map, then the standard parallels work out to almost exactly 45° N/S. This results in similar pinching to the tangent case, though not quite so bad, but with stretching at the equator to balance out the reduced distortion at the poles.
I also noticed that your landforms conform a bit to well to the rectangular map to look natural. Trying to fill things in neatly is a natural inclination you need to try to overcome when making up fictional terrain. Try to avoid aligning things, particularly north-south or east-west.
Your biome placement and mountains also look a bit off to me, but I'm not so strong on geology, climatology, and ecology. You should probably try to separate the geology from the climate/biome. Mountains may affect the climate and ecosystem, but they aren't a climate or ecosystem in and of themselves. You can have a wide range of different ecosystems on mountains. We have fairly drastic variations in precipitation here in British Columbia due to the mountains. An individual mountain range usually isn't very wide, so when you have a significant area with mountains, it tends to be a sequence of parallel mountains with valleys in between. When most people who don't live in western North America think of as "The Rocky Mountains" is actually a lot of mountain ranges crammed together including the Coast, Cascade, Columbia, Insular, Olympic, Rocky, Sierra Nevada, and Sierra Madre mountains. Squashed in among them are everything from rainforests to deserts. I think there's only one place on Earth where a large contiguous area has been raised above the treeline rather than just peaks or ridges, and that's the Tibetan Plateau.
Also, mountains are associated with boundaries. No necessarily coastlines, but where they lie between two sections of flatter land, those two sections tend to be discrete "lumps" rather than one cohesive lump with a mountain range through the middle. Ranges that violate this, like the Urals, tend to be old and worn down as the boundary they were created by has fused solid. Concentrated "lumps" of mountain in isolation from any sort of linear structure are also a bit un-natural looking.
@jbgibson - Thanks for all the pictures, I see what you mean. I'm changing my canvas size to a 1:2 proportion to get it as close to realistic as possible. I wasn't planning on showing the poles, no, so here's a question - changing the map to 2:1 proportion, would not defining the poles in the extra space be alright? By mixing it in with the water background, I mean. I'm pretty sure I understand what you're saying - because of the curvature, the landmasses closer to the poles should be widened to accommodate for the smashing that happens when properly projected onto a sphere. Got it. This map is being created as a reference for all the smaller, regional maps I'm going to create from it so I'm assuming that account for the distortion is still necessary, right? I'll do it anyway
@ManOfSteel - Thanks for the links, already looked at "PCK: Climate maps' and that's a really good reference; I'll be sure to check out the others too.
@Hai-Etlik - The futher explanation is very much appreciated. I want the map to be able to conform to a "Equidistant Cylindrical" projection as close as it possibly can without the whole thing needing to be changed, instead of having some decent looking map that can only be explained by the fact that it's fictional fantasy. Ah, the continents do square up, don't they? I'm stretching out the canvas right now so I'll be moving the continents around, making the NE one larger, so I will try and place them more naturally! Thank you for pointing that out, I was worried about that happening.
Most of my mountains placed were previously planned either for the story or from the conception of what I wanted the continent/island to look like, so I haven't been trying to shape the mountains around the climates or vice versa for the same reasons you stated - they don't all arise from steppe or rainforests. I have actually been to the Rocky Mountains twice! I understand exactly what you mean. I'll look up the Tibetan Plateau, thanks
Here's an example of what I'm slowly doing with the mountains:
This is the range in the middle of the western continent, by the way. I already edited it somewhat last night, replacing about half of it with the grey for moderate mountains and dotting 4 points outside it to account for wayward 'peaks' (not really peaks, just where the elevation gets high enough to differentiate from the landscape); the grey inside of the black is to account for valleys inside the range.
Here's how it overlays with the sketch-style mountains I placed:
(That's using a brush set modeled after Tolkien mountains I think I found here. I'm not a hundred percent set on using that brush, but for now that's what I am using.)
So this is how it looks on the brown background (the lighter the mountain, the more worn it is):
Anyway, what I've been doing is plopping down the color black for the area where I want a mountain range and then I'm detailing it in a bit as a kind of rough guide for later. You can see where the different mountains overlap that the brush mountains get smaller and disperse based on the high/moderate markers and the climate 'borders' set on the climate map (I think I should name these maps better - saying 'climate' five times in a sentence sounds awful!). The climates for the mountain ranges on the climate map are influenced by those around the mountains and with some I'll cut the climate color in where it dips into a steep or particularly large valley and such like that, but I'll largely keep it colored as a mountain. The only-grey ranges are low, somewhat-easily-crossed ones (I'm thinking of slightly taller, more condensed - in width - versions of the Appalachian Mountains as an example - the elevation rises moderately and more like with hills than steep cliffs). I hope that doesn't sound too repetitive or convoluted; it makes sense in my mind but explaining it is a bit difficult.
Thanks again for all the input, guys. I'll post an updated map probably Wednesday or Thursday
Life's gotten busy and as such have hardly had a moment to update the map.
Breakdown of little that has changed:
Shaped all the SE islands except for the largest.
In the process of shaping the north, center(?)-east island.
Shifted the map around for a 2:1 proportion.
And cleaned up the Mediterranean peninsula somewhat.
This map includes the ocean currents; pink is warm, purple is cool. Haven't had much time to edit the map but I have been researching climates and ocean currents. It's hard applying our planet's ocean currents to this fictional map, especially if you get into complicated rare-birds like the Somali current, that changes direction twice a year. Sooo if the currents don't match up perfectly with the climates (of course they don't - I'm no expert here) then I'm going to write it off as product of something special, I don't know. I think that even with my amateur knowledge it's okay and pseudo-realistic.... Thoughts?
Oh and the shading on the top and bottom of the map represents the poles. Not necessary, I just felt like adding it because - well I felt like it.
(PS, before someone else notices, yeah I'm going to change the warm current on the far left. Just realized it goes in the opposite direction of how it should - oh well, it was the first one I did. I'll get on fixing it.)