# Mapmaking Discussion & Philosophy (WIP/Critique) > Regional/World Mapping >  [WIP] Building a world from tectonics onward

## MrBragg

Alright, so I've been working on developing a tectonic model for my world for a while now and think I finally have a rough draft that isn't too embarrassing to show.   My goal is to get something that plausibly follows the "rules of tectonics" that I can then use as a base for determining geography, climates, etc.  The model is probably a bit on the simple side right now, and the coasts here are still a very rough draft (plus this resolution made blobs out of my island arcs...), but at this stage I think the plate motions and interactions make sense; the colors follow the standard scheme--blue = subduction, red = divergent, green = transform, pink = convergent (orange is for old / failed rifts).  The plates are named after departed cabinet secretaries since finding proper names is another project and, like their namesakes, any of these current plates could come and go without warning  :Wink: 

With Plate Labels


Without Plate Labels


I'd be really curious to hear if anyone has any comments / critiques on this tectonic model before I move on to refining the coasts and/or trying to add some more "interesting" tectonic regions and/or beginning to get started on working out everything needed for climates.  Thanks in advance!

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## CTA

I'm no expert (trying to build a tectonics map of my own), but this looks super cool! I do have a question about the Kelly plate. I would assume you would have more divergence on the border with the Sessions plate, since it's directly opposite the direction of subduction, than on the border with the Pruitt plate. What is your rationale here?

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## MrBragg

Thanks!  

Kelly's motion is a bit hard to depict on a static equirectangular projection like this, so here's an animation of the motion in orthographic from 16 Ma - present (teal = Kelly, orange = Pruitt, purple = Sessions).  You're completely right that there's greater spreading between Kelly and Sessions than Kelly and Pruitt; there's actually a bit of a rotational component to the motion between Kelly and Pruitt, which, combined with being relatively close to the pole, makes the motion a little weird looking in equirectangular.  Hopefully that helps to clear up!

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## Tiluchi

This all looks excellent! If I had one small critique, it's that the subductive margin on the southern Tillerson Plate looks quite irregular, in a way that's difficult to find on Earth. With irregular plate boundaries like that I'd expect to see more offshore volcanic arcs and back-arc basins, as is the case with the western edge of the Pacific Plate or the Mediterranean Sea between the Eurasian and African Plates.

The subductive margin wrapping tightly around 3/4 of the Comey Plate also makes me a bit uncomfortable, and my sense is that the slab pull from all that subduction would make the continent rift apart in the middle. But I'm far from an expert and it looks like you've put quite a bit of work into GPlates so I'd believe you if you said it's plausible with the tectonic history and all  :Wink:

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## MrBragg

Hey Tiluchi, your previous tectonics projects were a big inspiration for me, so I'm glad you're here so I can say thanks!

Totally valid critiques, too.  The subductive margin on the southern margin of Tillerson is quite irregular--it's also quite an oblique margin--so I think you're entirely right about this being a good place for some nice back-arc basins.  Adding these in is now on the to-do list.




> But I'm far from an expert and it looks like you've put quite a bit of work into GPlates so I'd believe you if you said it's plausible with the tectonic history and all


Believing me is likely a mistake  :Wink:   My thought with Comey was that this scenario of being almost surrounded by subduction would be similar to Laurasia before the breakup of Pangea, where the reconstructions I've seen have subduction on most of its sides.  Obviously it did eventually break up, but the reconstructions have the encircling subduction persisting for quite a while.  The current Sunda plate is also bounded on 3 sides by subduction, so I thought such an arrangement could be stable for at least a little while. You have a lot more experience here than I do, so I'm very much open to being convinced otherwise.

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## MrBragg

Small edit adding the back-arc basins suggested by Tiluchi and also beginning to very roughly sketch in where some mountains should be based on current and past tectonics (+ some really old mountains where things were otherwise boring).

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## MrBragg

I decided to take a stab at doing some ocean currents, and this is what I managed to come up with.  A few of the more horizontally-flowing currents I wasn't quite sure how to color, so I largely left them as neutral (black), which might not be how to properly handle them.  In any case, if anyone has any feedback I'd be happy to hear it  :Smile:

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## MrBragg

Apologies for the thread spam, this is probably (hopefully!) the last one for a while.  Anyway, here's an attempt at pressures and winds for Jan and July.  There are quite a few places where I'm not sure if I'm doing things correctly, so please don't be shy with comments / criticism!

Jan


July

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## Charerg

Overall looks pretty good. Getting the pressure zones right is always a bit tricky, especially over the continents. But while I might have done some things a bit different, you're definitely on the right track. I'll probably post something in the way of more detailed feedback once you get to the later stages, keep up the good work  :Wink: .

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## Josh Foreman

Really great work!  I'm going through the same process on my world so it's good to see how others are approaching it.  I'm no expert enough to give you any good feedback other than "keep it up!"

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## MrBragg

> I'll probably post something in the way of more detailed feedback once you get to the later stages, keep up the good work .


Good job building suspense  :Wink:   I'm currently working on figuring out / fighting with Wilbur so I can have at least a crude hiehgtmap before moving on to the next steps that require rough elevations.  This--together with figuring out what geography is appropriate for the various regions--is taking me a fair bit of time, so it might be a little while before I get to the next stages, but I'll definitely appreciate any feedback whenever you're able to provide it  :Smile: 





> Really great work!  I'm going through the same process on my world so it's good to see how others are approaching it.  I'm no expert enough to give you any good feedback other than "keep it up!"


Thanks!  Encouragement is very much appreciated!

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## MrBragg

Ok, so I created a criminally-simple outline of topography and, with that as a base, took quite a few stabs in the dark and made temp / precip maps.  Doing the temperatures felt ok, but I have much less confidence in the precipitation maps since a lot of those felt kind of like voodoo; in a lot of places there doesn't seem to be enough rain, but I don't really have a lot of intuition for what's reasonable here.  In any case, here's what I came up with:

Criminally-simple topography (colors in 1000 m increments)


Temps: Jan / Jul
 

Precip:  Jan / Jul
 

I fed these into the climate script and, after hunting down some subtly mis-colored pixels, got a result.  I haven't spent much time mentally processing this to find things that don't make sense (or editing out the abrupt transitions), but figured I'd put this up here to solicit thoughts.  In particular, if anyone has thoughts on the precipitation maps and where I'm missing rain, I'd love to hear them  :Smile:

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## Charerg

Well, I went ahead and did my take on the currents and the pressures to get an idea of how the climate patterns should turn out in my view. The oceanic circulation ended up similar to the one you did, with some differences here and there. Keep in mind that doing ocean currents for a fantasy world is a matter of interpretation to some degree, so this isn't necessarily "more right" than the original. That said, feel free to adopt whatever features you like.

Currents:

* *









In regards to the atmospheric pressures, it's largely the same story: the overall pattern is similar to the pressure maps you made, with differences here and there (some of them affected by the slightly different currents).

Pressures:

* *





January:


July:




So, looking at the climate maps, the temperature maps are probably ok, but the precipitation could definitely use some work. Looking at the climates, this turned out to be an extremely arid world, which probably doesn't make sense with these landmasses. The first thing that pops out is the equatorial dryness, the areas covered by the ITCZ should receive vast amounts of precipitation. Although looking at the topography (which is criminally simplistic, indeed  :Wink: ), you appear to have a lot of coastal mountains (maybe a bit too many, some of those could be partially island arcs, for example), but I still think the interiors would receive more rainfall than 0-10 mm during the wet season.

Especially the eastern continent, which doesn't have giant mountains all along the coast, should be a lot more wet along the equator. The mid latitudes seem suspiciously dry as well, even well past actual desert latitudes. Some polar steppes turn up right along the coastline of the southern continent, which doesn't seem a likely scenario. So I'd say you could definitely increase the precipitations almost everywhere beyond the desert latitudes (20-30s).

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## MrBragg

Wow, thanks for the detailed feedback!  I'm glad someone else agrees that my precipitation is messed up  :Wink:   I think I'm clearly missing something, so back to reading for me.

In the meantime, you gave me an idea re: getting rid of some of the coastal mountains.  In relatively recent geologic history I have the eastern coast of the west-central continent being a retreating subduction zone, so I think there's at least some justification for turning that Andean range into a bunch of back-arc basins and island arcs.  I sketched that change in and also went ahead and amalgamated your current / pressure ideas with mine, so here's where things stand while I work on figuring out what I'm messing up with the precipitation.

Currents


Jan / July Pressure and Winds

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## MrBragg

I went back and redid the precipitation maps (twice, actually) and managed to eliminate most of the arid-hellscape problems of my first iteration.  Turned out that a lot of my problems stemmed from not having much overlap between the summer and winter ITCZ positions, so increasing the ITCZ size a bit and pulling it closer to the equator for both seasons helped put rainforests where they should be.  If anything it looks like I now have too much _Aw_, particularly across the middle of the western continent, though maybe this isn't unreasonable.  The BWh cropping up right along the coasts of the two northwestern continents also seems a bit odd, but it wasn't clear what the justification would be for adding precipitation in that region.  I'm also still contemplating breaking up the Andean range on the eastern of those two continents to allow in more extratropical storm precipitation, but I'm 100% sold on that idea yet.

Precipitation, Jan / July
 

Climates, take 2

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## MrBragg

Took a break from planet-scale things for a bit to work on a tiny corner of one continent to try and get my head around Wilbur.  Definitely still have a lot to learn, but I've finally managed to get results that aren't facially ridiculous, so I'll consider that forward progress  :Smile:

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## MrBragg

To resurrect a seemingly dead thread, I've been toying around a bit with topography on the relatively small scale of a few hundreds of km, focusing first on some back arc basins / volcanic arc off the eastern coast of one of my larger continents.  I'd say the goal here is "plausibly abstract realism" with a resolution of ~1 km / px, so I'm not necessarily aiming to depict every ridge and valley but hopefully the overall layout of topography and relative heights of things make at least some semblance of sense.

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## Harrg

Nice. It`s looks good. I really love worlds like yours, made in a similar technique

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## Ilanthar

Looking good! Nice level of details.

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## MrBragg

Thanks both of you!  Hoping the process gets a little bit faster as I work at it, though we'll see...

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## QED42

> Took a break from planet-scale things for a bit to work on a tiny corner of one continent to try and get my head around Wilbur.  Definitely still have a lot to learn, but I've finally managed to get results that aren't facially ridiculous, so I'll consider that forward progress 
> 
> Attachment 126427


This looks really cool, what process did you use for this?

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## MrBragg

Hey QED42, sorry I didn't see your post here until now.  The process isn't really any special and is kind of an amalgamation of techniques I've seen on here.  Basically I start in Gimp by making a few layers of high frequency grayscale noise; for each layer, I set the color levels to be between certain elevations (e.g. 0 - 150 m, 800 - 1000 m, 3700 - 4000 m, etc) and then give each one a layer mask.  From there I can paint on the topography I want at each elevation by erasing the mask (using a variety of brushes I've collected), so it's basically a lot of time spent zoomed way in trying to paint features that make some amount of sense.  Once I'm happy with how the large and medium scale things look, I read the heighmap into Wilbur for a little erosion and incise flow before sending it back to Gimp for the final color gradient.

Here's the latest piece I'm ~ done with for now.

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## Harrg

I love your results. I see you are using a Wilbur shader for the shading. If you are using Photoshop you can achieve the same effect simply by using a heightmap. But get more control over it.
Copy the heightmap. Create an alpha channel. Insert your heightmap into the alpha channel. Create a new layer. Fill it with gray (half gray is sufficient). Choose filters, lighting effects. Choose endless light. In the settings, set the alpha channel with the height map. Move the sliders as you like. The most important thing is extrusion. In real time, you can extrude your map and make it three-dimensional. Now you can apply techniques to your map that real cartographers use for real maps, like Tom Patterson
https://www.shadedrelief.com/tutorials.html

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## Charerg

Nice to see you're still working on this! I see you've fallen into the rabbit hole of building up realistic-looking topography, and what you've showcased so far looks really great.

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## NethanielShade

I love this thread! Always great seeing other maps starting with tectonic plates. The ocean currents look really familiar, any chance you used Artifexian's tutorial whilst making those?

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## MrBragg

Thanks for all the kind words!  It's definitely a rabbit hole, or maybe more of a black hole... ;-)




> any chance you used Artifexian's tutorial whilst making those?


Glad you like the tectonics!  I've actually revised things a bit since the last post about them, so at some point I should post the updated model.  For the currents, I actually used the guide on this forum (https://www.cartographersguild.com/s...ad.php?t=27782) together with looking at maps of Earth's currents like this (https://upload.wikimedia.org/wikiped...erless%293.png).

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## MrBragg

So I've been fiddling around with tectonics some more (because masochism is fun!) and, since misery is much better with company, I wanted to solicit opinions on hypothetical scenarios.

Basically, I'm experimenting with having a "Tethys like" scenario early on during the supercontinent stage (~250 Mya), with a ridge that is destined to be subducted between the northern margin of the ocean between two halves of the supercontinent.  When that subduction happens (~225 Mya), the northern margin of the southern continent should rift off and begin heading north.  At around the same time--the precise timing doesn't appear to matter all that much--I also have the northern and southern halves of the supercontinent splitting, so a rift exists the entire way between them.  Up until now, things seem fine.

 

After some time, there should be an oceanic-oceanic margin developing between the "A" and "B" fragments (~175 Mya).  My inclination is that B should be subducting under A here as basically a continuation of the margin under the continent, though it also seems feasible that this could be more of a region of diffuse deformation and be more akin to a transform boundary.  If either of those options seem wildly incorrect (or wildly correct!), I'd appreciate opinions.  Lastly then, when the continental fragment on B collides with A (150 Mya), the question remains with what to do with that same pesky margin; if it's subducting, does subduction cease, or does it instead spread along the continent-ocean passive margin?  If it's not, would the two plates basically fuse together?  Again, opinions are appreciated  :Smile:

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## Tiluchi

Ah, nothing like the rabbithole of plate tectonics, where you can always make things more complicated!  :Wink: 

It's always tough to suss things out without playing around on GPlates myself, but I think my instinct here would be to have the southern A/B margin as more or less a transform boundary, and have it running northwest to southeast, somewhat parallel to the direction of microcontinent B. The other option might be to have something like what you have at 150 Ma, with the subductive margin extending southwards beyond the continent; this is perfectly normal in plate tectonics as far as I know, though I might expect the subduction zone to keep moving to the west as there's no continental margin to stop it; this is more or less what happened with the Scotia Plate, and I think maybe the Greater and Lesser Antilles. 

But these are all just guesses and I'm by no means an expert- getting a realistic tectonic history is a cycle of constant frustration for me, even though I find myself steadily happier with my results as I go on...

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## Charerg

You could also use the subduction of the ridge ca. 250 Mya as the driver for the breakup. I'm guessing this is more-or-less the scenario you were envisioning, with a hinge-type rotation between the separating landmasses. In essence the, eastern portion of the "southern plate" is subducting, while the western portion is diverging. After initial break-up, the rift would spread further east, with a piece of the southern plate breaking off. I guess the end result is largely the same, but I thought it was worth mentioning.



After the separating piece collides with the northern continent, it would be expected for the subduction zone to "jump over", and subduction to continue until the mid-oceanic ridge has been subducted. What happens beyond this point gets a bit complicated.



The subduction might cease (depending on the relative montions of the plates), since slab-pull would no longer be a factor. However, unless the two continents merged into a single plate (with a mass of oceanic crust in the middle), a new rift would have to form. This would likely form over continental crust. Like you mentioned, another possibility is that the subduction continues, in which case the continents could return to the initial hinge-type movement, eventually colliding. It's also possible that another portion of the southern continent would break off, repeating the cycle.

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## MrBragg

> getting a realistic tectonic history is a cycle of constant frustration for me, even though I find myself steadily happier with my results as I go on...


One of the truest things I've read in a long time  :Wink: 

@Charerg, yep, we're definitely on the same page, you just said it better than me!

Appreciate both of your feedback!  I actually tweaked things a bit and made a smaller Cimmeria-like block break off first rather than the bigger microcontinent; "Cimmeria" now collides with the northern continent before the cycle more or less repeats itself with the ridge subducting and then the rift jumping south and breaking off the microcontinent later (it will still eventually hit the north).



I've also followed the evolution a bit farther in time to the next big event happening in this region, which is a microcontinent-arc collision that happens around 100 Mya on the southwestern flank of the northern supercontinent (A).  Given that the oceanic crust to the east of that arc is quite old, I have the subduction polarity reversing, placing A under slab pull and thus initiates breakup of the northern supercontinent.  This part is more of a reach, but it also seemed reasonable that, which this change in direction of A, the subduction zone to the east of A might extend itself around to the west, consuming that old oceanic crust from both sides.

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## Charerg

Looks good, though I'd drop the subduction zone extending westwards. This scenario would place the adjacent oceanic crust under slab pull in both directions, forcing a new ridge in the middle of that sea. That would also conflict with continent A shifting direction and breaking apart (as it would no longer be under slab pull in this scenario).

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## MrBragg

> That would also conflict with continent A shifting direction and breaking apart (as it would no longer be under slab pull in this scenario).


Doh!  It's so obvious after you point it out...

Ok, so with the offending subduction zone removed, at 100 Mya I end up with the following scenario.  Moving forward, since C has lost most of its northeastern slab pull forces, it changes direction to a more northerly vector.  This, in turn, changes the nature of the C-B interaction from being simple convergent subduction to a retreating subduction zone.  My current thought is to treat that as something of a Kermadec-Tonga situation where a piece of B--likely including a chunk of the continent in the south--gets ripped off and a new spreading center opens.  That will evolve for a while, until I can think of what else to do with it.

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## MrBragg

Alright, so continuing to hack away at this and (hopefully!) make some progress.  This is the current whole-world state of things at the "present" age; all of the boundaries in the saturated colors seem to check out as reasonable from gplates while the lighter boundaries are places not fully fleshed out and are more just rough ideas (dashed red are incipient or recently failed rifts).  In particular I don't really like all of the intra-oceanic subduction happening in the far north and far west of the map as those types of boundaries don't really seem occur so extensively on earth.  The northern subduction arises from when the supercontinent over the north pole breaks up, so I'm not quite sure what to do there other than keep extending the subductrion zone as the fragments drift apart.  I'll keep thinking about this region, but if anyone has any brilliant ideas for how to handle it--or to tell me it's fine and to stop obsessing  :Wink:  --I'm all ears!

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## MrBragg

I've finally gotten around to cleaning up the last tectonics iteration and have something that I like a bit better than my previous attempt.  The history at least is more consistent and I've gotten rid of some of my all-land-is-surrounded-by-subduction problems.  The boundaries here are still roughly depicted, but if anything seems grossly implausible please tell me before I settle on this as "final" and then discover something off in a year  :Wink: 


Attachment 131668

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## Tiluchi

Looks great overall! I'm assuming that tectonically complex bit around the equator will turn into an Indonesia-style archipelago of microcontinents, yes? I've also struggled with random oceanic subduction zones going off the edge of continents in my own world, and it can be frustrating, but I think what you have there is fine. Perhaps an Alaska-style peninsula on the northwest of that western continent would help it look a bit less incongruous? Otherwise hard to say without seeing the GPlates animation.

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## MrBragg

Thanks Tiluchi!  You're right about that messy area being an Indonesia / Oceania style archipelago, I just haven't actually added the land there yet.

I like the idea of trying to add in a peninsula to the northwestern continent.  I can imagine that kind of thing being consistent with either an original part of the continent that split off during the breakup (rough gplates sketch) or as being something that accumulated over time as a series of terrane collisions a la real Alaska.  Added to the to-do list!

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## MrBragg

It's been forever, but I finally "finished" version 2.0 of my tectonics.  I think I've fixed most of the ugly stuff, so now I just need to not stare at this for too long before I find anything else I don't like  :Razz:

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## Charerg

Definitely a great improvement! Kudos for sticking with it all the way to the end, I know getting a satisfying tectonic layout can be a huge pain.

Great work and looking forward to seeing more  :Wink: .

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## MrBragg

Thanks Charerg!  Definitely wouldn't have been able to get here without all the help I've gotten from you and others on here, so kudos back  :Smile: 

It's only a relatively small perturbation from the last round, but while I still have ambition I've tweaked the currents / pressures to account for the modified landmasses.

Currents:


Pressures (Jan / July):

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## MrBragg

Sure, it's mostly water, but there's also some experimenting with island topography in here.  The intended scale is a ~1750 mi / side square, so none of these are supposed to be all that big.

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## L1qu1dN1trog3n

I always find island topography particularly hard, but that's an artefact of my need to keep a constant zoom level to avoid very disparate amounts of detail. What you've got here looks very nice though!

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## MrBragg

An attempt at something a little bit larger scale, this time an island ~ the size Madagascar but at 60 N.

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## AlittleMango

Oh i am loving this kind of detailing, always wanted to focus on a tectonically accurate map myself and you are doing such a stunning work
excited to see more once you have another update!

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## MrBragg

> Oh i am loving this kind of detailing, always wanted to focus on a tectonically accurate map myself and you are doing such a stunning work
> excited to see more once you have another update!


Thanks!  Ask and you shall receive:  Here's a first attempt at a full scale continent.  Each "bar" on the graticule is 100 mi, for a sense of scale.

Please feel free to critique anything here.  It's better to find out what I'm butchering now before I get too set on anything  :Wink:

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## morne

Bra-vo. Seriously amazing work. Those have got to be the most naturalistic mountains I've seen come out of Wilbur (with a very large amount of handcrafted work lending to that result, I'm sure). You've _got_ to do a write up on your process at some point.

If I had one nitpick, I guess it's the the river valleys in the lowlands are pretty uniform and narrow and seem to almost represent canyons based on the contours. But again, that's a very minor nitpick.

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## MrBragg

Thanks morne!  The mountains definitely benefit from some really nice brushes, so Wilbur and I can't take all the credit  :Wink:   The process is actually nothing particularly special and is mostly a collection of various techniques I've learned on here.  If you're interested though I could detail it.

Regarding the river valleys, you're absolutely right.  The final river incise step is probably a bit too strong, though if I draw in the rivers in blue it does an ok job of covering that up and allows me to be lazy and not have to experiment with different processes.

EDIT: Thanks for the rep!  Just noticed that notification  :Smile:

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## Tiluchi

Agree with Morne, this is definitely some of the best Wilbur output I've ever seen! It's *almost* enough to get me to make the switch (but not quite, mostly because I'm on a Mac). Would love to see a tutorial for this process at some point.

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## Charerg

Well, this has advanced a lot! Congratz on finishing the first continent (which looks amazing, btw). 

Very solid work overall, and looking forward to seeing more!

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## MrBragg

Because topography can get boring, and because climate and topography can feed back on each other, Ive taken a bit of a detour into temperature modeling lately.  Months ago I followed the Azelor / Charerg / AzureWings tutorial here and I wanted to compare the results of that to the Clima-sim method covered by Nikolai Lofving Hersfeldt which generates temperature isotherms on the basis of a very low resolution input geography.

For all of these, no attempt was made to correct for orographic temperature changes and no modification was made to the Clima-sim output to account for the influence of currents (which it ostensibly already includes).  Apart from the input geography, all other Clima-sim parameters were kept at the default Earth values.

July Tutorial (left) and Clima-sim (right)
 

The July maps have pretty remarkable agreement between the two methods and there really are only (to my eye, anyway) very minor differences. This is really neat and makes me happier than it probably should.

January Tutorial (left) and Clima-sim (right)
 

For the January maps, the qualitative agreement is still pretty good, though the differences are much more pronounced.  The Clima-sim maps are a bit warmer at the equator, which likely doesnt impact all that much since its always going to be hot, and are also appreciably warmer at the poles.  Particularly in the northern hemisphere, the 0 C isotherm is quite far north, which pushes the C climates far to the north and eliminates the Dfc climates in the northernmost latitudes entirely.

Im not 100% sure what to make of this January discrepancy.  Perhaps the lack of land at very high latitudes allows for much better heat transport by the oceans and so moderates the high latitude temperatures a lot.  There could also just be a systematic temperature anomaly in winter that makes all of the Clima-sim output warmer than it should be.  I'm going to keep messing around with this, but wanted to post these results here in case they're interesting for anyone.

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## Tiluchi

Thanks for posting this! I have always wondered about the practical differences between the Azelor tutorial and the Nikolai's much-more-involved version. The latter honestly struck me as a great deal of additional work and processing power for what seems like a less-exact result. I was also skeptical of his results that seemed too warm at the poles for my liking (the final result for Teacup Ae had no south polar tundra despite having a large continent at something like 85º south). My initial guess is that the Clima-sim methods understate the cooling effects of having a great deal of land directly next to the poles, which is likely to result in extensive ice-caps and thus cooler temperatures even in summer than what an agnostic model predicts. Clima-sim even allows for inputting ice caps into the land cover map, but it seems this doesn't matter much. 

Of course, the Clima-sim algorithm is much more advanced than the Cartographer's guild model that much more strictly uses Earth as a base, and I'm not a climatologist and haven't fiddled around with Clima-sim at all. Perhaps there's something obvious I'm missing here, but to my eyes the results produced manually using the Azelor/Charerg/AzureWings method seem more plausible to me.

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## MrBragg

> Perhaps there's something obvious I'm missing here, but to my eyes the results produced manually using the Azelor/Charerg/AzureWings method seem more plausible to me.


Yep, that's the exact same boat I'm in here.  The results from the Azelor/Charerg/AzureWings tutorial *feel* more right, but I also know nothing about climate forcings and so am entirely unqualified to be making these judgements.  That the July results match up so well while January is so different is confusing, so I'm playing around with changing parameters somewhat systematically to see if I can't figure out why this is.  If I stumble onto anything interesting I'll definitely let you know  :Smile:

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## worldbuilding pasta

> Thanks for posting this! I have always wondered about the practical differences between the Azelor tutorial and the Nikolai's much-more-involved version. The latter honestly struck me as a great deal of additional work and processing power for what seems like a less-exact result. I was also skeptical of his results that seemed too warm at the poles for my liking (the final result for Teacup Ae had no south polar tundra despite having a large continent at something like 85º south). My initial guess is that the Clima-sim methods understate the cooling effects of having a great deal of land directly next to the poles, which is likely to result in extensive ice-caps and thus cooler temperatures even in summer than what an agnostic model predicts. Clima-sim even allows for inputting ice caps into the land cover map, but it seems this doesn't matter much. 
> 
> Of course, the Clima-sim algorithm is much more advanced than the Cartographer's guild model that much more strictly uses Earth as a base, and I'm not a climatologist and haven't fiddled around with Clima-sim at all. Perhaps there's something obvious I'm missing here, but to my eyes the results produced manually using the Azelor/Charerg/AzureWings method seem more plausible to me.


The warm south pole in that model is due to Teacup Ae's eccentricity, which causes stronger seasons in the southern hemisphere; the significantly warmer summers (and generally flat terrain of the southern continent) evidently prevent permanent glaciers from forming, and without that ice-albedo feedback the south pole stays remarkably temperate. Later runs with a formal climate model have largely confirmed this result (though that also helped highlight some of the shortfalls to my approach to determining precipitation).

There may be something similar going on here: If there isn't sufficient landmass at the south pole to maintain a large glacier, the overall albedo of the poles will be far lower and so they will be warmer compared to Earth's (you can play around with the ice cover in clima-sim to see if you can get different results, though; there's a certain inertia to global climates wherein the presence of a reflective ice cap can help keep itself cool in a situation where an initially ice-free pole might not form an ice cap).

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## MrBragg

First of all I wanted to say thanks for putting together your tutorials; they're super informative and I always enjoy reading your material  :Smile: 




> There may be something similar going on here: If there isn't sufficient landmass at the south pole to maintain a large glacier, the overall albedo of the poles will be far lower and so they will be warmer compared to Earth's (you can play around with the ice cover in clima-sim to see if you can get different results, though; there's a certain inertia to global climates wherein the presence of a reflective ice cap can help keep itself cool in a situation where an initially ice-free pole might not form an ice cap).


This is what I'm currently playing around with.  If I give the north pole partial ice coverage it dramatically lowers the northernmost temperatures and pushes the 0 C isotherm somewhat farther south than without the ice.  I don't really have an intuition for 1) whether it's appropriate to add this type of sea ice cover since there is no land up there (as you say, feedback is potentially quite important), and 2) whether the ice-free version accurately reflects the temperature distribution or whether that is "too mixed" and thus too warm in the winter.  As a baseline initial test, I'd be curious to see what ExoPlaSim predicts for a water world so I could compare that to a Cilma-sim water world output, I just need to find the time to run that test...

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## MrBragg

Ok, so another interesting tidbit is the comparison between calculations on Earth in January with 1) a starting ice cap on Antarctica, and 2) without a starting ice cap.  When the model starts with ice, things look reasonable enough, but when it doesn't... the south pole gets hotter than the outback in the summer.  This seems like a spurious result and, even if it isn't, does go to show the massive (50 degrees C!) dependence on the starting conditions.

With Ice (Left), Without Ice (Right)

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## Peter Toth

This is unfortunate as I'm come to rely on Clima-Sim for its supposed accuracy and its ability to automate climate modeling with a consumer PC. Are you changing the CO2 levels or any other parameter between the two simulations? Did you repeat the simulation to verify it wasn't some random error by the processor (if that's at all possible)?

I'm intending to move on to ExoPlasim and I'm wondering if this program is more accurate. I remember morne's experimentation lately that resulted in a desert that extends much too far north, so I'm very skeptical.

By the way, MrBragg, I'm highly impressed by your Wilbur results from a couple weeks ago. I'm experimenting with Wilbur as well to generate some realistic terrain, but I'm not easily satisfied by my results so far.

Looking forward to the completion of your conworld!

Peter

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## worldbuilding pasta

> 1) whether it's appropriate to add this type of sea ice cover since there is no land up there (as you say, feedback is potentially quite important), and 2) whether the ice-free version accurately reflects the temperature distribution or whether that is "too mixed" and thus too warm in the winter.  As a baseline initial test, I'd be curious to see what ExoPlaSim predicts for a water world so I could compare that to a Cilma-sim water world output, I just need to find the time to run that test...


1, Clima-Sim should determine sea ice cover on its own.

2, Not too sure what you mean by "too mixed". The general approach I'd advise if you're aiming to have ice caps is to begin by over-estimating the extent of ice, running the model, and then remove ice from areas that get over 0 C in summer (be sure you're looking at temperatures at the surface, not sea level), and iterate until you find an equilibrium.

Regarding the test you ran with Antarctica, there should indeed be a significant difference there--and you'd be surprised how warm polar regions can get without ice thanks to constant sunlight in summer. This might be overstating it a bit though; Clima-sim doesn't seem to do a good job of allowing heat to flow from the poles to lower latitudes when the former gets warmer than the latter, which is why it essentially breaks at higher axial tilts.

re: Peter, I took a look at morne's world and that high-latitude desert is a reasonable outcome of a large mountain range casting a large rainshadow. ExoPlaSim has its weaknesses (most notably the low resolution, static glaciers, and lack of deep ocean currents) but it's in a whole other league compared to Clima-sim in terms of the complexity and accuracy of the underlying simulation and its flexibility in handling a range of climate parameters.

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## Tiluchi

> The warm south pole in that model is due to Teacup Ae's eccentricity, which causes stronger seasons in the southern hemisphere; the significantly warmer summers (and generally flat terrain of the southern continent) evidently prevent permanent glaciers from forming, and without that ice-albedo feedback the south pole stays remarkably temperate. Later runs with a formal climate model have largely confirmed this result (though that also helped highlight some of the shortfalls to my approach to determining precipitation).


Thanks for that explanation! And thanks for the great posts on your blog, I recently completed your GPlates tutorial and I'm a Patreon subscriber. I'd missed the bit about Teacup's eccentricity, but that makes sense. A question however about the elevation: it seems that at the poles, elevation and the presence of ice sheets are somewhat endogenous to each other. For instance, most of Greenland would be below 1000 meters above sea level if it weren't for the presence of the Greenland Ice Sheet, which is 2-3 kilometers thick. The high elevation brings temperatures down, which allows for a continuing ice sheet- a feedback loop basically. I'm assuming that Clima-sim or ExoPlasim would give us ice cap climates near the poles if we were to include 2000-meter-thick ice caps in our elevation map inputs. So barring a detailed history of atmospheric CO2 for the world, maybe the presence of an ice sheet is a decision we have to make ahead of time as we're building the planet, rather than assuming from our geology that doesn't take into account the potential presence of thick ice sheets at some of the poles. 

What do you think? As I said earlier I'm not really a climatologist, and I don't have either of the simulation programs as I'm using Mac OS, so these are just my educated guesses.

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## MrBragg

> Regarding the test you ran with Antarctica, there should indeed be a significant difference there--and you'd be surprised how warm polar regions can get without ice thanks to constant sunlight in summer.


That it was warmer made sense, but the magnitude seemed off.  As a followup here I removed the ice from Greenland and saw qualitatively similar but somewhat less crazy warming of Greenland / Siberia / northern Canada.  My guess is that's due to the moderating effect of water near the pole, though removing half the land from an ice-free Antarctica still gives temperatures nearing 30 C in the summer.

Ice-free Greenland


As a point of comparison, I'd actually be really curious to know what ExoPlaSim predicts for the temperature of your southern continent in the summer to see how that compares to the >40 C predicted by Clima-sim.  Even with its systematic issues, I'd be much more inclined to trust the output from ExoPlaSim given how much more explicitly it treats things.

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## worldbuilding pasta

> As a point of comparison, I'd actually be really curious to know what ExoPlaSim predicts for the temperature of your southern continent in the summer to see how that compares to the >40 C predicted by Clima-sim. Even with its systematic issues, I'd be much more inclined to trust the output from ExoPlaSim given how much more explicitly it treats things.


I checked and it reached about 20-25 C in summer, but that's with years about 1/3 the length of Earth's (and various other tweaked parameters) so it's not a direct comparison to clima-sim's model. I've also recently been running a range of models of Earth at different temperatures (there will be a post up about it soon) and for Earth 10 C hotter than today on average, with fully melted ice caps (though topography not adjusted to account for that because it'd be a ton of effort) Antarctica reached around 30-40 C in summer. So all in all, yes, there's probably something funky going on with clima-sim here, likely because it's just not really designed to handle heat flowing away from the poles.




> A question however about the elevation: it seems that at the poles, elevation and the presence of ice sheets are somewhat endogenous to each other. For instance, most of Greenland would be below 1000 meters above sea level if it weren't for the presence of the Greenland Ice Sheet, which is 2-3 kilometers thick. The high elevation brings temperatures down, which allows for a continuing ice sheet- a feedback loop basically. I'm assuming that Clima-sim or ExoPlasim would give us ice cap climates near the poles if we were to include 2000-meter-thick ice caps in our elevation map inputs. So barring a detailed history of atmospheric CO2 for the world, maybe the presence of an ice sheet is a decision we have to make ahead of time as we're building the planet, rather than assuming from our geology that doesn't take into account the potential presence of thick ice sheets at some of the poles.


There is a valid point there, but if your ultimate concern is the extent of the ice sheets, then it doesn't really matter. The extent of a glacier is determined by its edges, where it's fairly thin; if those edges melt away, the interior will melt down towards the land surface, and if the edges are stable, the interior will be as well regardless of whether it's 10 meters or 4 kilometers thick.

Of course in reality, flow of ice from the glacier interior to the edges has a cooling effect that helps the glacier expand, and that will depend on the internal structure of the glacier, but glacial flow isn't modeled in ExoPlaSim (or clima-sim for that matter, but it's a bit easier to adjust glacial extent on the fly there) so it's a moot point. You kind of just have to accept that the model will underestimate the extent of glaciers in most cases. However, if your intent is to have an Earth-like world emerging from a recent ice age, it does help to run the model to balance first at something like 5-10 C colder than your intended temperature, and then warm it up from there. (Also ExoPlaSim does have the capacity to model the presence of deep glaciers on top of the topography, but doing so would require messing around with the running files and probably be more effort than it's worth).

Also, ExoPlaSim can run on mac, though it takes a bit more fiddling around; there's some notes on it in the readme on its github

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## Ottehcnor

Wow! This is an amazing amount of work with great results. It definitely has me wanting to re-do a map I'm currently working on to create a more realistic world.




> The process is actually nothing particularly special and is mostly a collection of various techniques I've learned on here.  If you're interested though I could detail it.


If you're serious about going into detail on your process, I for one would love to have that tutorial.

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## MrBragg

Thanks Ottehcnor!  At some point I'll cobble together all the different pieces of the methods that I've written about into something that is at least largely coherent.

By way of an update, here's an alpha version of the neighboring continent with some method tweaks to avoid carving out giant river canyons in all the highlands.

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## MrBragg

Another continent is finally in an alpha state.  With it, a hemisphere has a first pass of topography  :Smile:

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## Turambar

> Another continent is finally in an alpha state.  With it, a hemisphere has a first pass of topography


Well done! The level of topographical detail you get zooming in is very rich and realistic. I love it.

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## Tiluchi

As always this is amazing work! Your Wilbur maps have to be some of the most convincing I've ever seen, and hopefully you can post a tutorial at some point. If I have any minor quibble it would be that that southern continent doesn't quite fit in aesthetically with the northern two- I think particularly due to the irregular peninsula protruding northwards. On its own it's quite a nice-looking landform, but it makes it a bit harder to see how those three fit together (as based on your tectonic map it seems they were recently joined as one supercontinent. It's a very minor issue though, and I'm firmly in the "it's okay to move on if you've already put a lot of work into it" camp so I wouldn't worry about it too much unless you foresee some major reworking of the coastlines in the future anyway.

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## MrBragg

> I'm firmly in the "it's okay to move on if you've already put a lot of work into it" camp


I increasingly find myself in that camp with you  :Wink:   Your critique here is entirely legit; the part where these three were recently a single landmass was an addition that came after I had gotten somewhat attached to the general shapes.  My post hoc rationalization for the many little bays and gulfs that don't really fit together is that they're just flooded continental crust.  Not sure how plausible that is, but at the time it worked for my geologically challenged brain  :Smile: 

And who knows, maybe when I finally finish a first pass of the topography things like this will start to irritate me and I'll get an itch to go back and change things...

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## Charerg

I have to say I'm a little bit jealous of how quickly you manage to build up the topography (compared to my own sluggish pace  :Very Happy: ), and very nice quality as well. I wonder if you use a similar approach to mine (start at a lower resolution), or do you just build up the topography in a single pass? Looking forward to seeing more!

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## MrBragg

Thanks Charerg!  I mostly just use a single pass at the final resolution.  I say "mostly" because I do do an initial pass at very low resolution where I mark off regions of "mountains", "lowlands", "really tall mountains", etc, but that's more of a sketch than an actual step in building.  I've found this a good balance between wanting nice detail and being lazy  :Wink:

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## MrBragg

Another piece finally in an alpha state!

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## Peter Toth

As always, congrats on achieving such realism with your topography! I'm sometimes wonder if our methods have any similarities or common starting points. But if there's one thing I know for sure, your method is FAR superior over mine.

A question I've been wondering: When you determine your climate zones (I'm assuming near the end of your project), are you planning to reduce some of the erosion on some of your mountains where there is desert, or is the river flow / erosion already accounted for, assuming that you've already determined your basic climatology in advance? (In my case, I worked out the basic climate first, before detailing the topography, just to gauge where the river channels and erosion should be. When I'm finished the fine-tuning, however, I'm planning on doing a final run with ExoPlaSim using the T63 model, to finalize the climatology.

At any rate, keep at it, for I'm sure we're all looking forward to that final project!

Peter

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## MrBragg

Thanks for the kind words, Peter.  I think there's definitely some similarity between our approaches, though it sounds like you have way more patience for Wilbur then I do  :Wink:   Just about all of my work goes into getting the heightmap the way I want it in Gimp and Wilbur is just the final step to add the highest frequency details / rivers.  In any case I quite like your results and always enjoy when you post something new.

Your question about climate is a good one since there's definitely feedback between topography and climate.  Far back in this thread--after a few pretty disastrous initial attempts--I got a rough sketch of climates that seemed plausible given a rough idea of what the topography would be.  Using that as a guide, I use partial opacity masks to tailor the amount of erosion applied in Wilbur when I do the detailed topography; e.g. wet areas use 100% opacity while putative deserts use something like ~25% opacity.  It's an undeniably imperfect approach, and if I had infinite time and patience I could in theory iterate between topography and climate generation, though I'm hoping it captures things well enough to not be immediately offensive  :Wink:   I'm also planning to dig into ExoPlaSim once my topography is sufficiently done, so I'll be very interested to see your results since you'll invariably get there before I do!

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## MrBragg

Finally closing in on finishing the first round of topography here.  At this point I'll probably start playing around with ExoPlaSim a bit to try and figure out the extent of the ice cap on the remaining southern continent, then do a first pass there and then maybe take a bit of a break  :Smile: 


Downsized from the orig 24k x 12k

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## Peter Toth

As usual, the topography looks absolutely stunning. Is there a particular reason why you didn't include polar continents? I always admire the way some mappers can seamlessly meld two different projections to account for curvature near the poles. That is evident on your southern continent (on the bottom of your conworld.)

I'm looking forward to seeing the ExoPlaSim results. Congratulations on making it this far, for your are very much an inspiration!

Peter

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## MrBragg

Thanks Peter.  I actually did initially start with a south polar continent, but in order to get a decent tectonic model that needed to move a bit north and off the pole.  To account for the projection of continents with severe distortion (anything poleward of ~45 N/S), the gist is that I typically make the canonical map of a continent in oblique equirectangular and then reproject that finalized map back to normal equirectangular.

Now, onto my first foray into ExoPlaSim.  Before diving into ExoPlaSim, I need to give a shout out to Nikolai over at Worldbuildingpasta for his excellent introduction and overview of the program as well as for making his conversion scripts available.  Without that kind of support, this type of program would be totally inaccessible, so a big thanks!

Part I:  Resolution

I first wanted to get a sense for how the resolution of the input map affects the climate output.  I used input resolutions of T21 (32 x 64), T42 (64 x 128 ), and T85 (128 x 256) and kept all parameters the same between runs except for the addition of the physics filter for T85; all parameters were kept to Earth values except for the days / year, which I set to 360 to make math easy.  Using 16 cores @ 2.3 GHz, running these simulations from start to balance took roughly 6 hours, 24 hours, and 94 hours, respectively (~100 ± 10 model years), which scaled just about linearly with the increased number of pixels.  To generate the Köppen maps, I averaged 20 model years together (all after balance was achieved) and shifted the coldest month in the northern hemisphere to ~January; from there I output the climate map without interpolation or other fiddling with the defaults.



At T21 resolution its hard to make out much beyond vague climate bands:  Theres tropical, desert, temperate, and... not much else.  Things are a fair bit warmer than I would initially expect21.4 C global averagewhich is probably at least partially due to the lack of polar ice caps and lack of any land at the north pole (ClimaSim gave similarly warm northern temperatures).  Theres also likely a systematic temperature error:  Even when working with earth, Nikolai observed an average temperature of 16.5 C with a 300 ppm CO2 model, which is several degrees warmer than the 20th century average of 13.9 C.   Anyway, BWh also seems a bit more widespread than expected, but at this resolution a lot of nuance is just missing and so its hard to say too much more.



At T42, its immediately apparent how helpful quadrupling of the number of pixels is.  Areas that used to be flat Cfb or BWh are revealed to have a lot more texture, so thats nice and fun.  A lot of the systematic errors that Nikolai has previously identified are apparent hereice caps being too small, northwests of continents being too cold, and perhaps somewhat more expansive arid climatesand things are still too warm (20.9 C) to my totally untrained eye (though notably the seasonal sea ice has expanded quite a bit).   There are also still some other oddities; ExoPlaSim really seems to like hot deserts and goes so far as to put them at the same latitude as tundra just a few pixels away.  Generally though, this seems to capture the trends wed expect for a fairly warm planet.



Finally, as expected, T85 resolution is even more detailed and a lot less blocky.  Unlike the change from T21 to T42 though, the overall picture here doesnt change all that much; theres a lot more detail, but there arent really any regions of major qualitative shifts to the climate.  The temperature here is 22.1 C, making it appreciably higher than for either T21 or T42 and signalling that there may not be a consistent trend between resolution and computed temperature.

Overall, there seems to be a significant qualitative shift in going from T21 to T42 and a more subtle refinement at T85.  This is kind of good news for my planned approach, since it seems to indicate that already at T42 the major effects are captured and so I can refine parameters at T42 and wait until things are set before doing a final pass at T85.  I do like the improved detail at T85, so at the end I can probably justify the ~4 days of computational time that it takes.

Part IIish:  CO2



As a bit of a side experiment, at T42 resolution I also lowered the CO2 a bit to try and tone down the average global temperature.  Starting with the output from the 300 ppm model and then re-converging to balance at 230 ppm definitely results in significant cooling; the average temp drops from 20.9 C to 18.9 C, still quite warm but better than before.  The poles are affected much more strongly than the tropics (a southern ice cap starts to develop), which is consistent with our own current global experiment with CO2 levels.  Precipitations patterns also change, though there its a bit more of a mixed bag despite an overall drop in global precipitation.

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## Caenwyr

> The poles are affected much more strongly than the tropics (a southern ice cap starts to develop), which is consistent with our own current global experiment with CO2 levels.


You made me snort coffee out of my nose with that offhand remark. You monster!  :Wink:

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## Tiluchi

This looks amazing so far! Will be interested to see what happens when you compare the Azelor tutorial version with the output from ExoPlaSim. Still impressed you were able to get it all running- I took one look at Nikolai's code and turned tail and ran. 

Seeing these outputs makes me wonder if part of what's going on is that ExoPlaSim (and ClimaSim apparently) really like continental climates, and overstate the high summer temperatures that come with low pressure systems over land, or maybe understate the effect of high pressure systems in the wintertime. I don't know enough about how the program works to know if it's overestimating the atmospheric pressure itself, or just the temperature effects of that. Either way, maybe the trick is to figure out what attenuates atmospheric pressures systems (or their temperature effects) on Earth and determine if that also applies to our conworlds. But this is all conjecture, and I'm not really knowledgeable enough about climatology to say one way or the other.

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## MrBragg

> Still impressed you were able to get it all running- I took one look at Nikolai's code and turned tail and ran.


Haha yeah, there definitely was a learning curve, but it only took a few crashes before I figured out what was going on  :Wink:  

Regarding the pressures, those are things that ExoPlaSim also exports so in theory we could extract these and see how they compare to expectation.  There are actually several pressure variables written as outputs--some of which are broken down by atmosphere layer--so the trick here might be figuring out which information is relevant.  Something to look into...

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## MrBragg

After a little bit more work on fiddling with CO2 levels, I've managed to get global average temperatures closer to what I was hoping for.  I also reduced the planet radius from earths value to mine (3100 mi), which probably helps equator-to-pole heat transfer.

300 ppm (22.9 C)


180 ppm (19.8 C)


120 ppm (16.7 C)


After doing a number of these with different parametersand looking at the results from Nikolai and discussions with Tiluchiits pretty clear that the ITCZ doesnt seem to fluctuate quite as much as it should from summer to winter.  Even over land it typically doesnt deviate more than +/- 10 degrees from the equator and, when it does, it tends to be somewhat dry as compared to the areas over the ocean; this latter quality is illustrated really nicely by Nikolais figure here where large swaths of land in the tropics have underestimated precipitation while the oceans are overestimated.  Theres probably some systematic error with pressures going on here, but Ive not dug deeply enough to sort out what that might be.

In any case, at this point things are probably good enough to estimate the extent of glaciation on my final continent and finish the topography there before coming back and doing a final pass(es) in ExoPlaSim.

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## Naima

> Thanks Peter.  I actually did initially start with a south polar continent, but in order to get a decent tectonic model that needed to move a bit north and off the pole.  To account for the projection of continents with severe distortion (anything poleward of ~45 N/S), the gist is that I typically make the “canonical” map of a continent in oblique equirectangular and then reproject that finalized map back to normal equirectangular.
> 
> Now, onto my first foray into ExoPlaSim.  Before diving into ExoPlaSim, I need to give a shout out to Nikolai over at Worldbuildingpasta for his excellent introduction and overview of the program as well as for making his conversion scripts available.  Without that kind of support, this type of program would be totally inaccessible, so a big thanks!
> 
> Part I:  Resolution
> 
> I first wanted to get a sense for how the resolution of the input map affects the climate output.  I used input resolutions of T21 (32 x 64), T42 (64 x 128 ), and T85 (128 x 256) and kept all parameters the same between runs except for the addition of the physics filter for T85; all parameters were kept to Earth values except for the days / year, which I set to 360 to make math easy.  Using 16 cores @ 2.3 GHz, running these simulations from start to balance took roughly 6 hours, 24 hours, and 94 hours, respectively (~100 ± 10 model years), which scaled just about linearly with the increased number of pixels.  To generate the Köppen maps, I averaged 20 model years together (all after balance was achieved) and shifted the coldest month in the northern hemisphere to ~January; from there I output the climate map without interpolation or other fiddling with the defaults.
> 
> 
> ...


 ~4 days  ??? Wow that's dedication surely. I could barely wait 1 hour.
What pc do you have ?

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## MrBragg

> ~4 days  ??? Wow that's dedication surely. I could barely wait 1 hour.
> What pc do you have ?


Haha, I actually do a fair amount of computational chemistry, so my computer has 20 physical cores and I'm used to waiting days (or weeks) for results  :Smile:

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## MrBragg

Alright, apart from adding a few more hotspot chains, I think a first stab at topography is FINALLY done!  So, before I decide this is *the* version, let me know if anything doesn't look right so I can fix it  :Smile: 


Downsized slightly from 24k x 12k

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## worldbuilding pasta

2 quick notes:

1, I've done some tests lately with exoplasim runs starting with 1 meter of initial global glacial cover; it takes a bit longer for the climate to settle out, at least 50 years whereas they usually are mostly settled within 20 years otherwise, but the resulting glacial cover is a lot more accurate, as well as the global average temperature. it does make some mid-latitude areas even colder than they should be, though.



2, I've seen at least some indication that T85 runs are better at reproducing the precipitation patterns in Africa and India, but I've never really got around to fully investigating it; this is a run someone on discord did for just 16 years (and I think it's from back when we used an earlier version of the topography script that was heavily land-biased)

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## MrBragg

> 1, I've done some tests lately with exoplasim runs starting with 1 meter of initial global glacial cover; it takes a bit longer for the climate to settle out, at least 50 years whereas they usually are mostly settled within 20 years otherwise, but the resulting glacial cover is a lot more accurate, as well as the global average temperature. it does make some mid-latitude areas even colder than they should be, though.


This is a really good point and something I'll try soon.  Thanks!




> ... and I think it's from back when we used an earlier version of the topography script that was heavily land-biased)


Out of curiosity, what do you mean by this?  I'm guessing (hoping) this isn't the Image2sra_2.0.3.py script that I've been using.

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## Naima

> 2 quick notes:
> 
> 1, I've done some tests lately with exoplasim runs starting with 1 meter of initial global glacial cover; it takes a bit longer for the climate to settle out, at least 50 years whereas they usually are mostly settled within 20 years otherwise, but the resulting glacial cover is a lot more accurate, as well as the global average temperature. it does make some mid-latitude areas even colder than they should be, though.
> 
> 
> 
> 2, I've seen at least some indication that T85 runs are better at reproducing the precipitation patterns in Africa and India, but I've never really got around to fully investigating it; this is a run someone on discord did for just 16 years (and I think it's from back when we used an earlier version of the topography script that was heavily land-biased)


Am I wrong or places mediterranean in wrong positions?

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## MrBragg

> Am I wrong or places mediterranean in wrong positions?


That output almost looks like it came from one of ExoPlaSim's "snapshot" files, at least when I mistakenly use those to generate climates I get similar weird distributions of Med climates like in that example.  I guess it could also come from the fact that a 16 year simulation isn't yet converged, so it could have wacky thermal / precipitation parameters.

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## Naima

> That output almost looks like it came from one of ExoPlaSim's "snapshot" files, at least when I mistakenly use those to generate climates I get similar weird distributions of Med climates like in that example.  I guess it could also come from the fact that a 16 year simulation isn't yet converged, so it could have wacky thermal / precipitation parameters.


I guess I have to try to mess with that program too... but is it worth the whole job of installation and so on ? Its seeming overly conplicate to me if the result is getting a 256 pixel map when I usually work at over 20k scale ?

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## worldbuilding pasta

I think this was way back before Ostimeus had released the script anywhere so don't worry about it

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## Naima

> I think this was way back before Ostimeus had released the script anywhere so don't worry about it


What do you mean ? I was trying to follow the tut on WBP but i found a bit of confusion on where to put Low pressure circles.

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## worldbuilding pasta

> What do you mean ? I was trying to follow the tut on WBP but i found a bit of confusion on where to put Low pressure circles.


Sorry, was replying to bragg earlier regarding the image2sra script, I haven't used old-school forums in ages, I didn't remember how the reply stuff worked.

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## Charerg

Congratz on finishing the topograhy, MrBragg! I think you must be the first one to have finished a planetary-scale elevation map built with this kind of technique and detail (makes me think I should get off my lazy arse and get some progress done on my own project). 

It is also very interesting to see ExoPlaSim being used for climate modelling. Love seeing that this kind of simulation software (even with some things not being modelled) is available as freeware for the use of hobbyist like us these days. I have to admit that I might be a bit rusty when it comes to the climates, but at a quick glance the "big picture" seems about right in the simulation output (dry areas where they should be and so forth). Though I'm sure there's still a place for the more manual methods (such as the one used in Azelor's tutorial), I think it's very valuable especially for those less familiar with the climate-stuff to have a more model-based approach that is less reliant on the user's own intuition and knowledge.

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## Naima

Old post ... delete plz.

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## MrBragg

> Congratz on finishing the topograhy, MrBragg! I think you must be the first one to have finished a planetary-scale elevation map built with this kind of technique and detail (makes me think I should get off my lazy arse and get some progress done on my own project).


Thanks, Charerg!  I guess being stubborn does actually have some advantages  :Wink:   Would also love to see your latest map since it was one of the big inspirations for me.





> 1, I've done some tests lately with exoplasim runs starting with 1 meter of initial global glacial cover; it takes a bit longer for the climate to settle out, at least 50 years whereas they usually are mostly settled within 20 years otherwise, but the resulting glacial cover is a lot more accurate, as well as the global average temperature. it does make some mid-latitude areas even colder than they should be, though.


So I tried this at T42 and starting with glaciers did converge to a marginally cooler overall temperature at 300 ppm CO2 (22.4 C vs 22.9 C).  Starting with <=200 ppm CO2 resulted in a snowball, though, so the hysteresis caused by starting with glaciers may constrain the accessible final temperatures somewhat.

On a somewhat related note, @worldbuilding pasta, do you have any experience running resolutions >T85?  For giggles I tried everything larger and each and every one immediately crashed before the model even got going, even when using an identical input from T85 (only resolution and sra inputs changed) that worked fine.

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## worldbuilding pasta

> So I tried this at T42 and starting with glaciers did converge to a marginally cooler overall temperature at 300 ppm CO2 (22.4 C vs 22.9 C).  Starting with <=200 ppm CO2 resulted in a snowball, though, so the hysteresis caused by starting with glaciers may constrain the accessible final temperatures somewhat.


You might try running it first at 300 ppm for 10-20 years and then reduce co2




> On a somewhat related note, @worldbuilding pasta, do you have any experience running resolutions >T85?  For giggles I tried everything larger and each and every one immediately crashed before the model even got going, even when using an identical input from T85 (only resolution and sra inputs changed) that worked fine.


I haven't even done a proper T85 run yet, I wanna test it more but I've sort of paused my exoplasim work for the winter because of the energy costs here. It might be a ram limitation or something, it might need more layers, or it might be the same bug people have been having with t63 that I still have yet to investigate.

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## MrBragg

> You might try running it first at 300 ppm for 10-20 years and then reduce co2


Yeah, if I were super ambitious I could try that, though my results at ~120 ppm CO2 I think are already decent enough to move forward.  I've already baked my ice caps into the terrain anyway, so as long as the EPS output gets close I'm happy.






> It might be a ram limitation or something, it might need more layers, or it might be the same bug people have been having with t63 that I still have yet to investigate.


Ok cool, those were my first thoughts as well.  Going to 15 layers didn't affect it and the error I got was different than when I tried T63, which very clearly told me that that resolution wasn't supported.  For memory, EPS at T42 doesn't seem to use all that much RAM (I have 64 GB) and I can run a T85 and a T42 simultaneously, so assuming memory usage scaled ~linearly then I'm imagine at least T106 should be able to run.  Next time I run a T85 I'll pay closer attention to the memory usage during the cycles and make sure it never spikes higher than I'd expect.





> I haven't even done a proper T85 run yet, I wanna test it more but I've sort of paused my exoplasim work for the winter because of the energy costs here.


If it's at all helpful, I could run some calculations for you when my computer is open, so just let me know.


EDIT:  OK so I did some more digging and for T106 and T127 it looks like EPS is missing files it needs for those resolutions. For T106 for example, it starts out with the message "/home/users/.local/lib/python3.6/site-packages/exoplasim/plasim/run/most_plasim_t106_l10_p16.x...." and then crashes; for T85 and T42 this step passes almost instantly and then the model begins.  It turns out that the t106_l10_p16 (resolution_levels_processors I'm guessing is the nomenclature) file isn't present in the requested directory and neither are any files associated with T127.  So, unsure if this is an issue on my end or with EPS, but figured I'd post it here in case it's useful.

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## Naima

> Yeah, if I were super ambitious I could try that, though my results at ~120 ppm CO2 I think are already decent enough to move forward.  I've already baked my ice caps into the terrain anyway, so as long as the EPS output gets close I'm happy.
> 
> 
> 
> 
> 
> Ok cool, those were my first thoughts as well.  Going to 15 layers didn't affect it and the error I got was different than when I tried T63, which very clearly told me that that resolution wasn't supported.  For memory, EPS at T42 doesn't seem to use all that much RAM (I have 64 GB) and I can run a T85 and a T42 simultaneously, so assuming memory usage scaled ~linearly then I'm imagine at least T106 should be able to run.  Next time I run a T85 I'll pay closer attention to the memory usage during the cycles and make sure it never spikes higher than I'd expect.
> 
> 
> ...


What pc specs do you have?

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## worldbuilding pasta

I think it compiles the "most" files on demand for each configuration the first time you attempt to run it, so it's not that they're missing but failing to compile (or something fails before it even gets that far). I can shoot the dev a message that these resolutions still aren't working, but I think they've just been too busy to work on exoplasim for a while because there are fixes I know they've wanted to do for a while that they haven't implemented.

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## worldbuilding pasta

> If it's at all helpful, I could run some calculations for you when my computer is open, so just let me know.


If you really wanted to, I'd be interested to see what happened with Earth topography (max elevation 6300 m on this file) and standard settings (300 ppm etc) at t85 with 1 m initial glacial cover run for 50-100 years, to see if it fixes some of the issues at t42

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## MrBragg

> I can shoot the dev a message that these resolutions still aren't working, but I think they've just been too busy to work on exoplasim for a while because there are fixes I know they've wanted to do for a while that they haven't implemented.


Thanks!





> If you really wanted to, I'd be interested to see what happened with Earth topography (max elevation 6300 m on this file) and standard settings (300 ppm etc) at t85 with 1 m initial glacial cover run for 50-100 years, to see if it fixes some of the issues at t42


Yeah sure, can start that in a few days.  Quick question though:  for the Image2sra script, is the max elevation the script asks for the value corresponding to fully white (255) or the highest elevation in the image, regardless of its color value?  I've been assuming the former, but if it's the latter I'll make that adjustment.

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## worldbuilding pasta

You know, I think you might be right, so to be sure here's the map rescaled so the max elevation is white

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## Tiluchi

Just jumping in to say that that topography looks amazing! As Charerg said I think it's the first 100% complete planet I've seen done with Wilbur, so for that alone it's very impressive. Not sure to what extent you messed with GPlates, but you can input your finished map into GPlates by linking your continent polygons to the raster file, which might help in confirming that the geology makes sense from a tectonics perspective. 

My only *tiny* nitpick is that the coastlines in general look a little more irregular than we generally see on Earth- not sure if that's just an artifact of the Wilbur processing. I always have to look at the coastlines of Africa and Australia to remind myself that very smooth coastlines are actually quite common in many areas!

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