Getting starting with GIS for fictional worlds - how to build initial basemap/data?

[AzureWings]

I've been meaning to get into learning my way around using GIS software, and I think its use is a worthwhile skill to build. For the time being, though, all I really have to use it for is various fictional worlds I've made to various degrees - and for some where I've wanted a nice, organized way to put together things like maps of various demographic features and distinctions GIS seems like it would be well-suited to that sort of task.

However - I'd really like to learn my way around on my own geography, rather than on others in which I've much less emotional investment. In trying to start at the beginning I've run into the problem that the various tutorials and information I've been able to find all just grab an available dataset from one source or another to use as the base for a map, and have very little discussion on how said basemap/dataset/etc was actually constructed. Since most GIS in general use is concerned with the real world, this is reasonable and not very surprising, but it's little consolation to me when the first step in what I'm trying to do typically seems to be a matter left for the experts.

I'm not so concerned about constructing the content for the data itself - that's a different problem not quite so specific to GIS software, and one I think as it stands I'm already decently-equipped to deal with. But I'm not yet familiar enough with GIS software of any kind to know how that data needs to be packaged. In other words - what's the appropriate approach to constructing, say, a base map of land and political borders like that often seen of Earth, such that it will be usable in GIS software (for the time being I'm using QGIS, if that makes a particular difference). The borders themselves I've already got, if not necessarily in a vectorized format or even necessarily a digital one (yet), but I'm not sure how they should be formatted to work with QGIS and I'm having trouble finding any information out there that makes any explicit statement on the subject. I'd like to avoid sitting down and tracing a whole lot of borders only to find out that however I've gone about it has made a result that won't be very useful - for a land and political borders map, for instance, would simply manually constructing a polygon featureset by tracing out predesigned borders segment by segment and n-gon by n-gon suffice, or is there something 'special' about even a basic basemap that would be left out by such a method? While I'm quite unlikely to be aiming (or be able) to match real-world data in terms of resolution and precision, I'd like what data I do create or generate to be usable in the same manner as I could the real thing (since I'd like to construct an initial base to learn QGIS on).

To sum up, I guess the question is - what all goes into the actual file one would import into QGIS or other GIS software as the base dataset to begin mapping other features relative to, and how do I go about producing such a file (or is it really, really the same as any other featureset such that I could just build it out by hand from a blank canvas in QGIS itself)? I've seen some of the excellent pointers and guides posted here by Hai-Etlik (both the more general tutorial and the custom CRS info), but in looking around here and elsewhere I haven't found anything that quite covers how to put the base data together when not starting from Earth or some other dataset that someone else has already put together in a georeferenced form.

[Shenanigans]

It's entirely possible to go into QGIS and just start doodling. In my experience, the big value in software like QGIS isn't necessarily the drafting aspect, but being able to do relational analysis (How many trees are within ten feet of a road? Which towns are more than three miles from a river? How many Starbucks should be placed on one intersection based on the per capita density of plaid shirt distributors in the local area?). I doubt you're interested in this kind of information.

Also, since you're asking about fantasy realms, a lot of the first steps are kind of irrelevant. For example, in the real world, I would say that you should check your projection as a jumping off point. However, unless you really love your fantasy world, I doubt you have projections for it.

In short, go nuts. Fire up GQIS and play around. You're not creating migratory data, so it doesn't really matter what you do. You could probably just take a sample data set and clear it out for a brand new sandbox. I'm honestly not sure how much this will help you learn real GIS skills, though.

[AzureWings]

Thanks - and I do see what you mean, that much of the relational analysis capabilities might go rather unused in a fantasy context (though I'd hesitate to say they'd be entirely useless - the reason I was interested in using GIS for fantasy maps is that for some settings I'd had a number of different metrics I'd wanted to put together choropleth or other thematic maps for over the same geography - it might be interesting to see if I could use that sort of analysis on a regional scale to try and put together better correlations between, say, concentrations of population ethnicities and proximities and which lingua franca/trade languages are dominant in what regions as a result).

Hai-Etlik actually did cover the projections bit to an extent which was pretty neat (they had a thread on here about how to define a non-Earth CRS) so I wouldn't say projections for a fantasy world (if of course drawn directly from real map projections) are necessarily off the table .

As regards my original question, I guess - then to confirm, just drawing around in QGIS itself is a fine way to create base vector data - regardless of said data's actual quality, it would be in principle usable as a base to reference other data with respect to? I guess my real confusion was that from the information I could find I couldn't really tell whether there was or wasn't any 'special sauce' of sorts to a base dataset, since nothing really talked about constructing one, just fetching them from elsewhere.

[Shenanigans]

In summary, yes, you can just draw vector shapes. Generally speaking, any sort of special sauce is in the attributes table and the queries that use that data. ArcGIS is notorious for charging extra money for versions of the program with better analysis tools. With a properly populated table, your example of ethnicities and language use is totally viable.

Hopefully that helps. It's pretty neat software. I hope you have fun with it!