First foray into Digital Mapping!

[savarast]

Name: W.I.P
Radius: ~2,250km
Circumfrence: ~14,137km
Area: ~63,617,300km^2
Gravity: 0.97g
Composition: ~30% Platinum (almost entirely in the core), surface composition roughly as earth
Water Coverage: ~70-75%

Hello cartographers! I'm a long-time TRPG guy who started at playing 12 but hasn't touched this stuff in about 5 years (damn you reality). I used to do my mapping by hand but decided to give the digital route a go since it facilitates edits/changes to the world and also lets me easily visualize details such as mountain ranges, rivers, tectonics, etc. Anyways, this is the world map of my campaign setting from years ago re-imagined and would love any critique or feedback about its design so far. There are so many resources on this forum that I know I'll find tons of info there, but eyes other than mine will definitely spot things I'm sure are missing. One map is just the mask between water and land, the other is basic tectonic faults and climate overlay. I'm planning to update tectonics with the direction they are pushing, and of course climate doesn't exist in bands so i'll do a land climate map as well.

Any feedback is appreciated of course, but things I know I am concerned with are 1) is there too much "jaggedness" 2) are there too many islands/are their placements logical 3) assuming around 70-75% water, is there too much land? 4) How far inland from a tectonic plate can I logically place mountains (I was assuming at most 1inch)

Also, from an Aesthetic point of view I'm having trouble deciding if the details should be overhead view or from an angle. From an angle would allow my map to look more Tolkien/fantasy-esque, BUT as a global map, it seems the aesthetic choice is top down.

Looking forward to seeing everyone around!

[Gidde]

Welcome to the Guild! Have some rep for posting maps in your first post

Your planet is TEENY. Too small for plate tectonics to really be a thing. For comparison, Mars has a circumference of 21,344 km, and has been tectonically dead for ages. The teeny size also has a few other unexpected consequences like the curvature of the horizon being a ton more noticeable than it is here on earth, and a lot closer to boot. Personally, I *love* teeny planets for exactly the no-tectonics reason. Just account for the horizon effects and it'll be great.

Kudos on making your core heavy in order to get your gravity close to Earth's!

As far as too much land goes, nah, that looks fine! There's no rule saying that Earth's 70% must be followed.

[savarast]

@Gidde

Thanks! I didn't even consider the horizon but of course it would appear closer if the planet was about 1/4th earth's size. I always figured no matter the planet that if it had a molten core it would have some sort of tectonic activity. That being said that's not even that much of a problem because I kinda had the idea that a magical impact is what split the continents though I don't generally like the "magic" hand-waving type of solutions. Oh, but if the planet is too small of true tectonics, how would mountains/valleys form naturally? I kinda got to Platinum as the core because I was thinking "whats the smallest natural earth-like planet that could happen" and platinum turns out to be the densest naturally occurring element (I think its osmium which is denser but naturally occurring iirc). I'm also thinking to use this fact to explain part of the modern-era/future-era technology booms since Platinum is exceedingly useful in electronics etc. I also adjusted the density of the planet to account for the other lighter elements, originally I had the planet down to circumference of only 10,053km, but that would be assuming a near-100% platinum planet. As for the water, I guess whats most important is "is it natural looking" but you seem to think so, so that puts my mind at ease a bit at least!

Its actually crazy how much more thought should go in to map making, back when I did it by hand I was in my teens and just plopped things where they just felt right, this week I feel like I took an intro course to Photoshop, plate tectonics, climate, planetary birth, and cartography.

Oh, I'm also assuming since the planet is so dense any moon would have to be MUCH further away, anyone know orbital mechanics? XD

[Falconius]

Wouldn't the single rather large moon and the oceans also have an effect on Earths tectonics Gidde? Perhaps mars is tectonically dead because it lacks significantly in these areas. I'm sure gravity must play into the equation somehow too?

@ OP As for the land mass I also wouldn't worry too much about it, it will have some effects like making the lee side of continents drier than they end up on earth. They do look slightly too jaggy at this
world resolution though.

[Gidde]

Hehehe. I went really far down this rabbit hole before I chucked it all and went back to "what looks good".

You'll want to google "Roche limit", there will be formulas there for how close the moon(s) can be without breaking up. Speaking of moons, ours has some great examples of how to get mountains without tectonics: Lots and lots and lots of impact craters of varying size. Plus, your planet will have had tectonics before they died; basically the smaller it is the faster it goes solid enough to not have moving plates anymore. And that doesn't mean volcanoes stopped, so there's another way to get mountains. Again, look at Mars as an example: one theory of why olympus mons is so tall is because it kept erupting after the plates stopped moving. Your mountains will *not* be that tall though; Mars can get away with it because it has 1/3 the gravity yours has. So keep mountains around the size of Everest as an upper limit.

Edit: Falconius ninja'd me with a question

My initial instinct is that no moon that is small enough to be gravitationally bound to something with Earth's mass (we can tell that by the 0.97g gravity) is large enough to do any kind of tidal heating. So no love on keeping tectonics going. I'd have to do some math to be certain though.

[Falconius]

Well I think the utter denseness of this planet would also limit tectonics more, at the same time it would have greater/more-spectacular effects when it did have tectonics (more mass harder to move and also more inertia).

[Azélor]

A platinium core is a lot denser than the Earth's core.
It sounds reasonable to have no tectonic activity. It makes things easier I think but also less earthlike.
As mentionned by others, that does not mean the landscape is flat.

The south pole is either wrong or the map is cropped. It is not possible to have water and land at the same spot. Yes, the south pole is not a line but more like a point. Tought, your planet is small and probably less spherical than Earth? Or not because the gravity is the same? I'm not sure.

[Gidde]

I'm thinking since the density is so high, it would probably be HIGHLY spherical - Saturn is the most oblate planet in the system precisely because it's the least dense.

Edit: Quite obviously savarast, we are all intrigued by your planet!

[savarast]

[snip] The south pole is either wrong or the map is cropped. It is not possible to have water and land at the same spot. Yes, the south pole is not a line but more like a point. Tought, your planet is small and probably less spherical than Earth? Or not because the gravity is the same? I'm not sure.

Im figuring the world is roughly spherical just for simplicity's sake. Attached is how I kinda visualize how the south pole works, I think it works?

[savarast]

But, here's a thought: wouldn't the excess mass make the core even hotter or at least the same as earth? For example, a 4x smaller earth with earth properties I could see cooling faster given its constituent elements, but assuming a super dense core wouldn't the initial conditions heat the core to extremely high temperatures, and then it's density would make it harder to release heat? We might be over thinking it, but it's fun none the less as a thought experiment. I mean, either way I can work it out (like you guys said, volcanoes, old tectonics, meteors, etc).


In regards to the moon, I'll look in to the Roche limit, I think someone analyzed thanos' moon throw with that on YouTube. I think our moon has some effect on the tectonics (if only slightly?) but definitely on the ocean. To be honest I haven't considered the moon(s) yet, anyone have good resources as to what happens when there are more than one?