So, I've got this setting. It's a supernatural post-apocalyptic story involving guys with superhuman abilities traveling across an America that's become a grid of 2x2 mile "squares" (technically pillars getting bigger going up and smaller towards the earth's core), each governed by a different supernatural gimmick. One square might make people fall west instead of down, another might make it impossible to tell lies, another might start to mutate you into some kind of human-badger hybrid the second you step into it. The people who have survived one year into what's come to be known as "Gridfall" have established settlements in the least dangerous squares they can find, learned as much as they can about the other squares surrounding them, and worked out the safest paths from one settlement to the next.

This, naturally, means that maps will be made that take the new grid system into account, and will need to inform the reader of what exactly they need to look out for with regards to the rules or gimmicks of each square they pass through. That's a bit tricky though, because conventional maps generally don't supply that kind of information. Maps generally work with symbols and coded lines, things that can be easily explained in a simple map key on the side of the map, things that barely even take a few words, let alone whole sentences, to explain. But these maps are going to have to say things like "people become half a foot tall in this one, but the animals stay the same size as always", or "people spontaneously combust at random when they enter this one, avoid at all costs. And keeping in mind that this is the post-apocalypse, where resources are scarce, they're going to want to come up with the most efficient and straightforward method of conveying this information as possible.

What would be the most efficient way to make a map of an area that also explains how all the squares in that area work?

  • $\begingroup$ Does the width of the "pillars" expand as they ascend, so that all airspace out to the edge of the atmosphere (or beyond?) is within one pillar or another? Or alternatively, are the pillars a fixed 2 x 2 miles at all altitudes and there are wedges of "safe" airspace in between, infinitesimally thin at ground level but wide enough for air transit corridors at high altitude? $\endgroup$ Mar 13, 2021 at 4:57
  • $\begingroup$ how do you fit a square grid on the surface of a sphere? $\endgroup$
    – Jasen
    Mar 13, 2021 at 9:17
  • $\begingroup$ @KerrAvon2055 Yes, they're roughly 2x2 miles at sea level but expand to the sky and contract underground, like latitudinal and longitudinal lines. $\endgroup$ Mar 13, 2021 at 11:05
  • $\begingroup$ @Jasen: You can’t, but arranging rows of slightly misaligned squares can give you a good approximation, and if we’re positing changes to the laws of physics then there’s nothing preventing localised changes of topography to make them perfectly aligned when viewed from ground level. $\endgroup$
    – Joe Bloggs
    Mar 14, 2021 at 9:23
  • 1
    $\begingroup$ Realistically, people will develop a shorthand to quickly communicate the threat level and type of a certain grid square. An example of something like this is the PRT Power classifications that are used in Wildbow's Worm. In it, the powered individuals are assigned ratings that unpowered agents can use to quickly communicate. For example, if a parahuman is classified as a "Stranger", the operatives immediately begin using password and identity checks to prevent impostors and verify communications. $\endgroup$
    – Dragongeek
    Mar 15, 2021 at 18:08

3 Answers 3


As a baseline, the map will have a color coding in each area, sort of a heat map, ranging from e.g. red for the most lethal to blue to the practically harmless.

Then there will be one or more symbols to specify the type of local gimmick, and if it applies to general or special classes. Lastly, an indicator, either a symbol of a color, on the level of confidence in the classification.

Rationale: whoever started the map obviously started in a safe square and figured out that some other squares were more dangerous and other less. Therefore it will soon be safe to assume that any other square is dangerous unless proven otherwise. Once the exploration began and whoever returned started bringing information, more confidence can be gained. However some gimmick can be intrinsically more tricky: for example a square where anything taller than 1 meter above the ground will be cut to that height will be safe for a toddler accidentally roaming into it but will kill a parent trying to recover it, unless the parent is also crawling.

The more information are gathered, the more confidence one can put in the symbolic description of the square properties.

And since it is post Apocalypse, it's perfectly normal to have maps displaying uncharted areas, with basically just a "hic sunt leones".

  • $\begingroup$ Depending on the production capabilities of this Post-Apocalyptic world (or the MacGuffin-y nature of the map), you may also include an Encyclopedia-sized Guidebook that details exactly what the Gimmick is in each square according to its alphanumeric grid designation which would be increasingly necessary as an area the size of New Jersey would require roughly 2,000 squares with (I assume) unique gimmicks in each one. $\endgroup$
    – SirTain
    Mar 15, 2021 at 13:56

Story Maps:

In the post-apocalypse, I doubt you'll have cartographers making proper maps. You'll be lucky if people can properly travel at all. But where people CAN travel, there will be roads or at least rivers. And where each route lies, there will be a story. Your maps will tell that story with hints and reminders.

No routes will cross anything overly lethal. The actual maps would likely be either a written or detailed oral account of what happens to you as you travel the road, or some sort of prompt that reminds you of what is along the path. Since the blocks occur in such regular intervals, you might have a string with unique knots and colors or beads, and a verbal explanation of what each knot/bead means. Literacy is likely quite low, and as a consequence people will have better memories and memorize things more. A map would be a string of mnemonics to tell you what you face on the road.

Beads or knot-patterns could have particular shapes to represent which direction you should go at each new square - like beads with hole in the sides, or knots that mean "turn right/north" vs. "turn right/west." This map could even have side-strings to either show you alternate routes, or as warnings about especially dangerous side-steps in case things go wrong. I could even see a sort of weave or patchwork quilt made for an area, where each patch represented a square. An old grandma selling a quilt might be an invaluable guide to survival in a given region!

I doubt most people would ever have a proper map, especially not one they took with them. Each town would likely have a visual representation of the local hazards and a few old folks always ready to tell the travelers what they face if they go a certain way. Crafty and evil locals might lay traps for unwary travelers, like "Enter the square and go in 100 feet, then stop for a minute and watch out for giant birds," but actually you don't get oxygen in the square and will pass out within a minute (and the locals then dash in to steal the stuff off the dead travelers).

Overall, travel would be epically challenging, but a good bard who memorizes lots of stories of travelers would be worth any ten maps.

  • 2
    $\begingroup$ Established routes could have song lines that accompany mild/deadly heat maps. The PA world could take inspiration from Australian Aborigines. Each verse sentence/sentence pair/full verse describes the gimmick for each square along a particular route eg boston to new york (with warnings about straying from the path). If you veer too much off the song's course you either need to know which song to change too (maybe the map can reference the name of the songs for the common routes), or know that you are in danger of not knowing what's coming next. $\endgroup$ Mar 15, 2021 at 15:07
  • $\begingroup$ "Luddenden's a waarm shop, Roylehead's varry cold, And if tha' gets to Halifax Tha must be varry bold." $\endgroup$
    – A. B.
    Mar 25, 2021 at 13:10


The mappers of old had class D personnel who would try to traverse a square. The percentage reflects how many successfully traversed the square. 100% means everyone made it (example, no lying square). 50% means half made it (perhaps the random combustion square).

This is the old big map. It unfolds to 3 square meters. Each square is a centimeter and contains a percentage. Squares are coded by X Y coordinate numbers and letters.

Your characters have a unique map - a well worn version with additional detail written into the squares by a variety of persons over the years. Some are barely literate scrawls; others have notes about how the square contents could be helpful or other details. Some have different percentages written in - the opinions of subsequent authors. Once they are far from familiar areas they have just the percentages to work with. The fact that the map still exists and has not been lost is considered a testament to its accuracy.

I like this for a story because your characters could have names for the various persons who contributed to the map. Some are known personally to them. Others are lost to time and have nicknames.

Consider making your squares 10 miles on a side instead of 2. 10 square mile squares rendered as 1 cm each is where I got the 3 x 3 meter map. It would be hard to fit all the 2x2 miles squares filling America on any reasonably sized map.


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