How do I create geologically accurate regional maps without building a whole world?

[llopet]

I hope this is the right place to post this, it’s sort of complicated and I’m not sure if this is the right category. TL;DR, it’s a question about worldbuilding approaches/resources.

First, some background: I’ve been working on building up a fictional world for my current novel project. The world is not really intended to break any of the known laws of the universe (besides maybe a few, but nothing to do with anything that would show up on a map), so basically, it’s just going to be Earth with different continents. The main premise of my worldbuilding is to see how different of a planet I can end up with from Earth without changing anything dramatically (i.e., humans are still humans and facing a similar world). I have an idea of how I want my continents arranged (large polar continent at the North Pole which extends down to the equator in the east, equatorial continent to the west, and a small (Australia-sized?) continent in the south). The main action of the story takes place on the Southern Continent, which I’ve already got quite a few sketches of, and there’s some action later on in the southernmost area of the Northern Continent. Besides that, everything else is technically not relevant, although I would like to have some idea of how the continents are arranged/continental drift/etc, for planning out human and evolutionary history.

I’ve seen a lot of resources on here as well as other parts of the internet that are really great for figuring out scientifically-accurate pictures of a whole world, but I haven’t seen much for doing specific regions. If I had endless time on my hands, I’d love to create a world map, but currently I think I need to scale back my expectations. In that spirit, I’ve decided that the most important thing for me is working out interesting local features—any tectonic activity, geology, things like fossil deposits or mineral veins, etc—for the Southern Continent. I still don’t want to close off the possibility of creating a whole-world map at some point, though (I’ve caught a terrible case of the worldbuilding bug, if you couldn’t tell).

I guess my question has a few parts. First, should I just focus on making maps of the places that matter in my story? If I end up wanting/needing to expand the boundaries of the map, how hard will it be to retcon things, and what things should I avoid defining until I’m sure of my boundaries? Second, how should I go about creating the region-specific map if I want it to be scientifically accurate? Third, does anyone have any advice/tutorials/references for what smaller geological features I should be thinking about on my regional map? There’s a lot of stuff on the internet about volcanoes and mountain ranges, but not a lot about microclimates or unusual veins of rocks.

Apologies for the very long post; brevity is not one of my strong suits, so let me know if any of what I said is confusing. Hope this hasn’t been covered a million times already, I’ve looked through stuff but I’m still very new here haha

(I'd also love any advice about how to say no to worldbuilding I don't need to do, I'm currently having a lot of trouble setting boundaries there )

[Redrobes]

Personally I would draw the globe in a super rough outline and then pick a country that looks good to you and draw that in only a slight bit more detail. Have a vague idea where you might want mountain ranges and maybe think only approximately about plate tectonics but not stress out too much about them. In the country put your mountain ranges down and think about where you might want hills. Then draw a regional map and now plot out the height of the regional map a little more thoroughly keeping the heights in line with your country maps mountains and hills. From there you can then pick out where your drainage basins will be and then put in the rivers.

From there you can do your encounter maps for telling the story. If you then need to expand your region then you have at least a consistent idea about where your mountains went and where the coastline will head off of the map.

It really depends on what your trying to get out of the map. For some people knowing the exact countries may be important to your story. You may need a set of mountains to block off a route across the map to aid in the story you are trying to tell. I think its a good idea to know roughly what is off of the map and whether the sea goes out a long way or there is another country which might send ships over into your encounter map area for example.

But for physical geography only the most picky geographers will know that there is any kind of problem with the shape of a world. Our world has places which would be almost unbelievable if just stated as fiction.

I think its important to make sure all your rivers travel down hill and that they don't loop back and do other crazy things. I think people would notice that. But whereabouts mountains form and other geographical features are much harder to declare unfit. Your rivers flowing down hill implies that you do need to know the heights over your map and that is much harder to back port from knowing where your rivers are and trying to construct hills and mountains to make their locations plausible.

Again, personally, only once I have the rivers, hills and coastlines I think about where populations may form and where roads connect them weaving around hills and going over rivers at their crossing points. Plus there is resource locations like mines, farming etc. Then its easier to build it out. If your fantasy then think about where monster types also might have their populations as well as men so that there may be areas where men do not want to linger. I.e. sticking a dragon down in an area would significantly alter the population centers.

Other people may do it differently however...

[waldronate]

You sound like you want two things: the world should be just like Earth for familiarity / storytelling purposes and the world should be as different as possible from Earth because I AM AMAZINGLY DIFFERENT AND PEOPLE NEED TO KNOW THAT! Sorry, that last part was from too many years of too many people demanding difference in their maps that they end up never using and it was rude as well. I apologize, please forgive me.

To hit the difference part, just sketch in some vague areas in the world as you have suggested that you did and as Redrobes suggested. The less detail that you have in the big map, the easier it is to retcon things later.

For the familiarity part, think about the stories you want to tell initially and take a look at a globe (ideally a map of Earth about 1500 - the start of the Age of Exploration, before things got too muddled globally by Europeans). Find an area (or maybe three or four) that has the sorts of terrain (mountains, forests, etc.) that you want to tell stories about. You'd be surprised what you can find on a globe, especially if you're willing the fudge the scales by a bit (much above about 10% starts to really skew climates and stuff). By picking things pretty much from a real map, these local areas are guaranteed to be completely scientifically plausible.

If you have some areas that have to be connected for story purposes, you can usually paste together areas from similar latitude in the same hemisphere as long as you watch some obvious constraints (Los Angeles and Atlanta, for example, should never go right next to each other for any number of reasons).

Unless you're planning to end up with a giant detailed map of the world that's needed for storytelling, that's it. I have never really needed more than that (THEY will tell you it's because I lack imagination). Local areas for telling stories and having adventures, and top-level things for tales of far-away lands and connecting the local things. Again, the less detail that you have at the top level, the more outrageous the rumors and player-heard stories can be without affecting anything else (for example, the players hear that "The Fiddlupp that live over those mountains are like big purple octopi and will turn you into a beast of burden" when that's totally untrue because they have only one "p" in their names).

So, to take your questions in turn: yes, focus on the things you'll be using most. Add just enough glue around it to get to the next activity and provide rumors for hooks. How much higher detail is needed has a lot to do with your players, but the less detail at a high level, the harder it is to box yourself in. To be scientifically accurate, pick real-world areas unfamiliar in time and space to your players and use those. To learn about geology, study geology!

I understand the desire to go deep into the geology of an area, but unless your group is a bunch of mining engineers, you may be hard-pressed to get them to notice that there are rocks even when giants are dropping said rocks on their heads. Maybe a good perception check might have someone notice that the rock that broke open after bouncing off the mage is sparkly inside (the rock, probably not the mage), but that's unlikely to get pursued even so. With tasty monsters around, most players tend toward looting those monsters rather than looting the overall landscape.

[llopet]

Thank you both for your very kind and detailed answers! Redrobes, your suggestion for workflow seems very reasonable, so I’ll try to take a stab at it. I think that maybe once I have a presentable WIP I’ll post it here so that all the questions are a little less theoretical, I do really appreciate both of you bringing me back to a more realistic starting place though :)