In my opinion, every worldbuilder should do their own maps. Not only does it allow a worldbuilder a set of geographic references to rely on when trying to figure out what is in relation to where, but it also gives those same references to their audience, allowing them to better visualise the setting which the worldbuilder is setting their works in. Of course, this isn’t something most worldbuilders have a problem with. In my experience, most worldbuilders love to make their own maps, to the extent that several digital tools exist to help them with it. I do understand that this isn’t necessarily a universal passion, however, I would still recommend that those who don’t like drawing maps do their own anyway, not because it’s something you have to do to qualify as a worldbuilder, but simply because the worldbuilder themselves understands their world better than anyone else, and delegating the representation of that world to anyone else, no matter how detailed the instructions, will lead to inaccuracies to the original vision, sometimes for the better, but usually for the worse.
This is why I tend to do my own maps, and my own cover art. Even though there are far more talented artists who could probably render more aesthetically pleasing versions of both, I would rather have faithful representations than technically superior ones.
However, when it comes to actually distinguishing a good map from a bad one, I ultimately have four criteria, each in descending order of importance:
1: Does it convey all the information it needs to?
2: Is it readable?
3: Does it match up with the internal logic of the setting.
4: Does it match the theme of the setting.
Note that none of these metrics are directly about artistic skill, mostly because it doesn’t have to be. Ultimately, a map is a way to convey information to an audience. A beautiful map which is also unreadable and inaccurate is useless in that regard. It’s better to have a map which the audience can easily understand, and which the audience can use to find their way around the setting than to have what is essentially a pretty piece of backdrop.
This primary purpose of a map is also what makes the first criteria the most important. Ultimately, the whole reason to map out your setting in the first place is to allow both worldbuilder and audience to understand where individual points of interest are in relation to each other. However, what those points of interest are is determined by the kinds of stories which the worldbuilder wants to tell in particular. This applies both geographically and categorically.
The first sense is a rather straightforward one: a worldbuilder has no pressing reason to include any part of the setting which is not narratively significant. The audience’s main reason in referring to a map is in finding out where a location mentioned within the associated story is. This is easiest if only the immediate vicinity of the story itself is included in the map they are looking through. If a story takes place entirely in the city of Beijing, with only incidental references to locations outside of it, then it’s pointless to include a map of all of East Asia. For the purposes of this example story, the audience needs to know where the characters are in reference to Zhongnanhai, not in reference to Singapore.
The second aspect is a bit trickier to articulate. Generally speaking, when it comes to our world, there are two types of maps: terrain maps, and political maps. The former serves primarily to allow accurate representations of terrain features like mountains, cliffs, valleys, and hills. The latter serves to represent towns, cities, roads, borders, and other human-made distinctions of geography. However, in certain genres – fantasy in particular – a story might require a map which shows both terrain features and political divisions. This means it’s the worldbuilder’s prerogative to choose what categories of features are narratively important enough to be included into the map as a whole. A story which involves both political intrigue and travel across forests and wastelands would need to include both forests and cities, because the audience would need to know the locations of both to help understand the geographical context of the story they are experiencing. Likewise, if that story doesn’t involve forests, or wastelands, then it might be better not to include them in the map – just as it might be better not to include any type of terrain feature or political distinction which aren’t narratively significant.
Of course, there are exceptions to this. Sometimes, a worldbuilder wants to show areas outside of the one an immediate story takes place in, or wants to add additional features to the map which aren’t narratively significant. There are reasons to do this: to instill a sense of mystery or wonder, to introduce an entire setting all at once, or to locate a story in reference to other stories already completed. However, this should still be done sparingly, and any addition on top of what’s absolutely needed should be considered carefully.
The reason for this primarily comes down to the second criteria: readability. It’s not enough for a map to possess all the information the audience needs to know. It’s also important to make sure the audience is capable of reading that information off the map easily. This is an especially tall order when creating maps for print or paperback formats: in these cases, space can be incredibly limited, and it can be a real challenge to create a map that both possesses all the detail needed, and can still fit onto a trade paperback page or a phone screen.
There are ways to make a map more readable. Using clear fonts which contrast sharply with the map background is one way. Using different shades or colours for different types of major terrain types (or countries, or other major distinctions) is another. Clever arrangement of text, or using fonts and capitalisation in labels to telegraph specific types of features (say, one font for rivers, another for towns, with labels in all caps being major cities) can go some way in preventing confusion as well. One way to deal with maps which are necessarily feature-dense is simply to label them with numbers, and have each number correspond to a label in a key or legend.
However, the most effective way to ensure readability is and will always be simplicity: the more details and places and terrain features a map possesses, the more cluttered it will be. The less space there’ll be for readable labels, and the more visual information the audience will have to process to find out what they need to know. Choose what needs to be conveyed, and add the rest only if necessary.
Of course, that information also needs to be portrayed in a way which is internally consistent. This seems like a rather obvious criteria: if a story says two places are next to each other, they should be next to each other in the map. If a town in a story needs access to a river, that town better be placed next to a river on the map. However, there are also less obvious matters to consider as well: things like trade routes, travel times, weather systems, geographical barriers, all of the things that make a fictional setting more than just a bare backdrop for a narrative. These should be reflected in maps as well, if they’re being displayed at all, and generally speaking, a casual observer with some (but perhaps not a great deal) of knowledge in geography, meteorology, history, or sociology could take one look at a map of a setting without finding anything egregiously wrong after taking the rules of that setting into account. The last thing a creator wants is for their map to break the suspension of disbelief in a way which subtracts from the reality of the world they are being invited to inhabit.
One way to reinforce that reality is to achieve the fourth criteria: visual theming. While this is emphatically not an art tutorial, maps are by definition visual displays, ones which ought to reinforce the tone of the setting. This means that a map in a given setting might be improved if it takes cues from the genre it’s based on, or references the institutions within the setting that might have made it. For example, a map of a high fantasy setting can be made to look more like it belongs in that setting through the clever use of certain fonts, or labels. Cities can be rendered (as they often were in medieval maps) pictographically, rather than by dots as we do today. Likewise, a good choice of font and symbols can reinforce the feeling of a sci-fi setting – though I have yet to encounter a two-dimensional map which accurately conveys the three-dimensionality of space.
I should hasten to make clear that even a map which fulfills all four of these criteria exceptionally may not necessarily be a visual masterpiece. It may not even be all that aesthetically pleasing, but as I have already made clear, this is not an art tutorial. What fulfilling these four criteria will do is create a functional, useful, and effective storytelling and reference tool, which allows both worldbuilders and their audience to understand the locations of their setting relative to each other easily, while providing depth and believability to the setting it represents.