World Map WIP: Mountain placement
Long time lurker, first time poster. I've been making use of several of the tutorials and resources on this forum for quite some time (mainly with regard to a different map than the one I'm posting here, but that one is half-finished and needs a lot of attention before I feel it can be shown publicly), but now I'm trying to create a more or less 'fantasy-realistic' world, and this time I want plausibility.
The world is tentatively called Nauāt or Dhokṣāt (the grammar/dictionary of the naming language is still confined to a single Word page, and I have yet to figure out the exact difference in meaning between the two possible names), and for ease of populating it with humans it is basically Earth as far as size, gravity, atmospheric pressure and oxygen content, etc. are concerned, but with different continents.
The coastline is basically most 'rigid', in the sense that I'd prefer not to make any major changes to them unless I have to, around the continents 'Northania' and 'Southaria' (as I said, the naming language is far from complete). Coastlines I do intend to mess about with are those of the lesser islands of 'South Eastilia' and the strip of land stretching across the North Pole; the former I find too random and the latter looks much too weird when I run it through G.Projector.
Basically my question is whether this looks plausible, and specifically whether the roughly placed mountains seem to make sense. Also, I don't know if the enormous lakes, particularly in Southaria, are out of place or pushing disbelief too far; I kind of like them, though, and will keep at least some of them.
Well, your coastlines are rather off. You are using the Plate Carree projection (Normal Tangent Equidistant Cylindrical) to judge by the graticule (Which is a bit misaligned You shouldn't have any map north of 90° N for instance). That projection produces significant distortion toward the poles. If you draw on the map without that distortion, it means you've drawn the land with the opposite distortion to compensate.
So, in your case, the projection stretches things out east to west as you near the poles. As the land doesn't look stretched that way, it means the actual shape of the land is all pinched in toward the poles so that the stretching balances it out.
This is one reason real world maps aren't generally done in this projection, as the distortion it produces is particularly unpleasant (ALL projections will produce a similar amount of distortion, but they vary in how it distorts and where it distorts.
It's also odd that you have that land mass so perfectly centred on the pole. The huge peninsula sticking out off it also looks extremely odd and doesn't make any sense to my (admittedly limited) understanding of tectonics. The mountains look largely OK to me, except that peninsula again.
If Northania and Southaria are meant to be rifting apart, you might want to make the coastlines fit each other a bit better. They don't need to be perfect as it's the edge of the continent as a whole, not the coastline that's important but you places where you have matching promontories. Mountains along the rift zone are likely to be old and weathered like the Appalachians along the eastern US. You might have similar mountains in the south of Northania, or if there is a significant continental sea making up for the mismatched coastlines, maybe a chain of islands. If this is what you are up to, think of the two fitting together with mountains along either side of the seam, then moving appart. The new coastline would drop down a bit as this happens and will flood to form shallow continentals seas (The continental shelf). At least that's my understanding.
Last edited by Hai-Etlik; 07-20-2012 at 05:27 PM.
1. Are the mountain placements random?
2. Is there a reason that some or all of the mountains have to be where they're located now? I really think the best way to place mountains is to plot the tectonic plates, determine their direction of movement, and calculate where the collision, subduction, and spreading zones are. Your collision zones will generally give you your highest mountains while your subduction zones will determine most of your volcanic arches and island chains. If your present mountain placement cannot change then you kind of have to do the same thing in reverse. Determine whether a specific mountain range is generated by the collision or subduction of plates and then make that the edge of a plate with the junction of the plates directly under a collision zone range or the junction of a subduction zone range slightly landward. A spreading zone can also generate a more disperse line of volcanoes and/or volcanic fissures.
For instance, the first thing that came to mind when I saw your map was the solitary mountain range along the coast of Northania. You could have a Northania Plate that comprises most of the continent of Northania. But there could also be a North Oceana plate that comprises most of the ocean floor off the coast. The North Oceana plate is moving NNW due to spreading on its opposite side. It has collided with the Northania plate, and since it is a lighter ocean plate, it is diving beneath the Northania plate forming a trench just offshore and a string of volcanic mountains along Northania's coast. This range could be as disperse as the Cascades or as spectacular as the Andes. That long, narrow peninsula jutting out from the main continent could be a result of a string of volcanoes that have spread and merged, much like Central America.
Last edited by ManOfSteel; 07-21-2012 at 11:36 PM.
That Arctic 'continent' had been bugging me quite a bit already (at the time I posted the map I intended to remake it so that it was nothing but the 'peninsula', stretching across [going north, over the pole, and back south on the opposite side], but I had not yet got around to fixing that), and the more I look at it the more I feel it has to disappear. I may simply remove all of that landmass north of about 45°N, and I may possibly expand the remaining piece of land to the southwest somewhat, so it's less of a strip.
As to projection distortion, I've been thinking about it, and forgetting about it, as I generated the coastlines. I'll try to keep it in mind more for my next iteration of the map (the projection of which I haven't decided upon yet), as well as figuring out just how I want the coastlines to look 'in reality', as it were.
I'll also try to read up on/get a better a grasp of tectonics, which is something I've tried to think of when placing the mountains, but felt fairly inept about, which means that the mountain placement isn't entirely random, except in the sense that that's where I wanted mountains, trying to figure out why/if they belonged there. The coastlines by the sea between Northania and Southaria will be made to fit the two continents together better as well.
Speaking of which, those worn-down mountains, would they be on either side of the sea, or only the one?
The oversimplified cliff-notes version :
Originally Posted by Certhbor
Things that cause mountains:
* On the front edge of a moving continental plate (for instance: the Andes continue to grow, as South America continues to push West, further away from Africa, which it used to be connected to.
* Were two plates are rubbing against each other going in opposite directions, causing them both to "scrunch" up a bit (for instance: California, around the San Andres fault)
* Where a continent is colliding with another continent (example: India's in-progress collision with Asia, which is creating the Himalayas)
* Volcanic activity (which also usually occurs near fault lines at the boundaries of plates)
Old-worn-down mountains are from places where these things took place in the geological past, but now things have changed:
* Example: the Appalacian Mountains were created when proto-north-america collided with proto-Africa. Later, the mid-atlantic rift opened up and they started moving in the other direction, and have been eroding ever since
* Exampe: The Ural mountains, formed when proto-europe collided with proto-asia. The plate has since fused solid, so there is no longer a fault there, and the mountains have been eroding ever since.
Continental plates can fuse together (e.g. Asia and and Europe, at the Urals) or break apart (i.e. Africa's Great Rift Valley), which changes where the fault lines are. New mountains occur near current fault lines, the old worn down ones places where there used to be a fault line, but isn't anymore.
That is... way over simplified. To the point that someone will probably point out some gross inaccuracies . But it may be helpful as a high-level overview.
Edited to add: I managed to say all that without actually answering your question . If you look at Africa/North America/Appalachian mountains as a model, they are on one side. The continent is probably going to split where the crust is a bit thinner, not at the peak of a mountain range.
Last edited by LindaJeanne; 07-22-2012 at 03:42 PM.
My understanding is they would tend to occur on both (Old convergent boundary re-opening) or neither (A new rift opening), though they might be more pronounced on one side or the other, or the subsidence as they rift might flood the mountains on one side but not the other.
Originally Posted by Certhbor
Well, having gone back to where I ought to have started, I've tried making the tectonic plates make some sort of sense. As I was rather fond of the general shape of the continents, I've tried to keep them fairly close to their original shapes – with the exception of dividing 'North Eastilia' into two landmasses (C and D in the new map) and reshaping the landmass now labelled F – and so I've attempted to put the plates in 'on top', as it were.
Of course, what seems like it might make 'some sort of sense' to me will probably look completely off to someone who knows the first thing about tectonics, so I thought I'd offer up my most complete WIP for scrutiny before I get in over my head.
The orange lines are the edges of the plates, the orange icons describe the type of activity at the particular edge where they appear; I hope they make sense. The larger arrows placed (more or less) in the centre of each plate indicate its general movement vector. The continents, marked by grey/black lines, are also marked by a lighter shade of their plate's colour. Continent outlines are very rough, as are the plate outlines (particularly around the poles), and will be made more interesting once I've solidified the tectonics more.
The parts I'm most unsure about are:
- the polar regions, where (a), on the north pole, I'm not sure the blue plate can be subducted along the entire northern coastline of C, nor what happens along the edge with the green plate (continent F in the upper map), and (b), on both poles, whether a split is plausible in these regions;
- the small red plate off the eastern coast of continent A and the plate which is mostly continent C, both of which I'm struggling to see just how they might work with the surrounding plates;
- the narrow eastern peninsula on continent B, which is mostly on the brown 'North Sea' plate, strikes me as odd, but I don't know whether to simply remove it or if some other division might make it less 'odd';
- the purple plate between A-B and F (could this plausibly be a part of the blue plate to the north of it, if its vector etc. are changed to match the latter's?);
- the green ocean plate east of A and B – the more I look at it, the more I wonder if it makes sense at all, or whether it ought to be split roughly along the north-south axis (though this would make it difficult to match eastern A-B to western C-D-E …).
Also, looking at maps of the tectonic plates on Earth I notice there are comparatively small plates, and wonder whether I need more of those to make this world seem plausible.