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May the Hex Be With You

What hex maps are, and why they’re Good

There’s a fairly subtle division amongst RPG cartographers: those who don’t like hex maps and those who do. Members of the former group prefer more artistic mapping styles, with iconic symbols, fills and textures, judicious application of colour, shadowing, even effects to make a map look old. I happily submit that the results can be stunning. But I also say, leave artistry to the artists. Having none myself, I like the hex map. In fact, I’m a big fan.

What is a Hex Map?

Hex map of Trid

Hex map of Trid

To be clear, hex maps are maps in which each hex represents a single terrain type. I’m not talking about a regular map with a hex grid overlay—that’s just artistry with hexes for reference. No, I’m referring to a map composed entirely of little hexagons, each with their own terrain graphic, with the assumption that—regardless of scale—the terrain shown dominates the entire hex. This, by the way, is usually why artistic folks disdain the hex—terrain hexes make for a limited palette, and hex maps can look monotonous; at worst, one hex map looks like every other hex map, regardless of map scale or what’s actually being represented. Understandably, the artists cringe.

But for non-artist OCD nerds like me, that’s actually the beauty of hex maps.

Why Hexes are Good

Hex maps are a staple of wargaming, the progenitor of roleplaying, so it’s no surprise that RPG maps would be well-represented with hexes. There’s definitely an “old-school” quality to hex maps, but there are some practical reasons behind the nolstagia.

Hexagons are nifty little polygons, given their ability to tessellate regularly. This means that a hex grid is continuous, comprised of same-sized hexes. Hex grids are preferable to a square grid because, unlike squares, the distance from the center of one hex to the center of adjacent hexes is equal; the result is that you can more easily determine distances in diagonal directions. Scaling is also made easier with hexes: you can sub-divide a single hex with a number of smaller, equally-sized sub-hexes for measurement and terrain detail within it. The overall benefit is that you can quickly drill-down from say, an atlas-sized map to a local area, while retaining scale and avoiding a lot of extra math. This was exploited to great effect by Judges Guild, who used a standard scale of 5 miles for each wilderness hex, which was five 1-mile hexes across, and each of these were five 0.2-mile hexes across themselves; the benefit was that you could use the same template to represent different sized areas, just by changing the scale of each hex.

Visually, hex maps provide crucial information in near-instant fashion: terrain distribution, location of special features, and precise distance between locations, for starters. Want to know how far it is from Point A to Point B? No need to measure—just count the hexes in between and multiply by the map’s scale. Need to know how long it takes the party to get from Point A to Point B? Divide the distance by their travel rate to determine hexes per day, then adjust for the terrain of each hex traversed.

If the measure of a map’s worth is its ability to clearly illustrate features, scale, and distance, then hex maps are—almost empirically—without peer. In fact, depending on what you’re mapping and the quality of your terrain hexes, the reader could probably identify everything without the aid of a key. For example, take a look at the hex map above. Say what you want about hexes being repetitive and dull—I still bet you can pretty much tell exactly what everything on the map is supposed to be.

Hex Math

If you know the length of one of the hex’s edges, area and width is easy to calculate:
Area
There’s a standard (and scary-looking) formula for determine hex area. Luckily for us, it can be distilled to an approximate value, where “t” is the length of one of the hex’s six edges:

Hex Area = 2.598t^2

Width
The width of a hex can be represented in one of two ways: across sides or across corners. Across sides, or short diameter, is the distance between parallel, opposite sides. Across corners, or long diameter, is the distance between opposite vertices. In each formula, “t” is the length of one of the hex’s edges:

Hex Width (opposite sides, aka short diameter) = 1.732t
Hex Width (opposite corners, aka long diameter) = 2t

Length
Let’s say you know the distance across the hex, but don’t know the length of an edge. Assuming you know the hex’s scale, just reverse the appropriate distance formula above, using “w” to represent width:

Edge Length (side-to-side) = 0.577w
Edge Length (corner-to-corner) = 0.5w

Hex Map Resources

There are several hex mapping resources available on the Internets, but here are some tried-and-true tools:

Need more?

October is hex month, and we have a bunch of hex-related articles coming in the next few weeks, including a couple of software reviews, a set of hex templates you can use for your own campaign, and a new approach to campaign design based entirely on the hex map. Stay tuned…

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  1. Eric Sprague
    November 6th, 2009 at 08:49 | #1

    The area of a hex can also be determined by the following formula:
    Hex Area = 0.866 x (smallest width)^2
    (http://www.drking.plus.com/hexagons/misc/area.html)
    Thus Hex Area = 0.866 x (5 mile hex)^2 = 0.866 x 25 = 21.65 square miles.
    This is a little quicker because you only need to know the distance side-to-side across a hex (i.e. the hex scale of the map).

  2. November 6th, 2009 at 23:12 | #2

    Yes – I was looking for this formula, and believe it or not, I couldn’t locate it anywhere on the Internet, my reference books, even a math textbook. Thanks for posting it, and the link.

    You’re right – this is a much easier way to determine area, if you know the distance between the hex’s flat sides. Thanks again!

  3. Greg MacKenzie
    June 29th, 2010 at 14:58 | #3

    The Hexmapper tool suggested above can be obtained from the Arr Kelaan fansite HEXMAPPER HAVEN REDUX: http://games.groups.yahoo.com/group/hexmapper_haven_redux/

    Anyone can freely join this group and post. The software formerly released by Arr Kelaan is available in the files section.

  1. March 6th, 2012 at 12:56 | #1

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