Monday, October 27, 2008

Mapping with Hexes

Hex Paper - one of the signature items of the RPG hobby. Originating in the board and counter games of Avalon Hill, hexes formed the basis for mapping nearly all of the early settings. When miniatures returned to widespread use in RPGs hexes were scaled up to be used on battle mats.

For mapping there is a big gotcha in using hexes. Unlike grids it is not as straight forward to use when you are drawing multiple maps to be joined or expanding the scale of a larger map. The advantage of using hexes was that it offered quick and easy management of sub maps and handling movement.

Note: You can click on the thumbnail to get a full image.

There are two types of hex grids



Of the two vertical is by far the most popular used. The examples in this post will be using the vertical hex grid.

Hexgrids have several choices how they can be formed.

These are rectangular hex grids.

You can make the end columns even in number.

You can make the ends uneven in length.

The last arrangement is used when you sub dived a large hex into smaller hexes.

Joining Maps

If you are just mapping one region and that all then you don' t need to worry about how to join two hex maps together. However if it is going to take multiple maps to completely cover your campaign then this issue needs attention

Unlike rectangular maps hex maps will have some degree of overlapping. This is because for vertical hex grids the top and bottom are uneven. It is possible not to overlap however you have to alternate two different hex grids.

There are two other ways of handling the vertical joining of two hex grids.

A half overlap

A full overlap

Of the two I prefer the half overlap. It slightly spreads out the vertical coverage of each individual map and I only have to copy the top and bottom hex every other column.

The horizontal joining has several types.

If you use a hex grid with uneven numbers of hexes you can lay them side by side with no overlap.

Judges Guild in the Wilderlands of High Fantasy was one of the first publishers to deal with this issue. They used 18 hex maps arranged in a three maps across 6 maps vertically. Each Hex maps had 52 columns, and 34 rows on the odd columns (1,3,5, etc) and 33 rows on the even columns. The resulting hex grid had uneven ends on the left and right edges.

They decided to use the half overlap to join the maps on the top and bottom edge. However they messed up on the left and right edge and decided to make them overlap. Because of the even ends of the hex grid this resulted in a staircase effect as below. Each map to east was a half row south of the map to the west.

For hex grids that have even ends you can do a full overlap of the last hex column with the first hex column of the next map.

I prefer the full overlap option as it helps ensure that I am correctly drawing from one map to the next. The same reason applies to the half overlap option.

Numbering Hexes

For vertical hex grids the numbering system is XXYY where XX is the column number and YY is the row number. This is reversed for horizontal hex grids.


Judges Guild is famed for having a complete mapping system that goes from campaign level of 5 miles per hex to a regional level of .2 miles per hex and finally to a local level of 42.24 feet per hex. Each larger hex was subdivided by smaller hexes 1/25 th the size of the larger hex. Hence the odd number at the local level.

If your scale per hex is an odd number (5 miles, 25 miles, etc) it is easy to draw up a subdivided hex as shown below. You pick a center hexes and count the remaining hexes outwards. You can use the six points to draw up the six sides of the larger hex.

Hexes with a even scale (10 miles, 30 miles, etc) are not as easy to subdivide. The lines you will be drawing for the sides will be meeting in the center of hexes.

There is alternative for drawing even scale hexes but you will lose the center hex. You will have decide which form is best to use for you game.


Bobzilla said...

Hex maps were something I never understood the need for on the larger scale maps. I could see the point on building maps as they were usually miniature scale so worked well but when you had a map of country hexed out I could never see the point. If it was for movement rates etc I always found it easier, and more realistic, to calculate each journey separately. Why delay a journey by a day because one of the hexes has a hill in it when you know that in game the hill could be climbed in 3 hours.

Boris the Bagger said...

For my gaming experience the hex maps are helpful for large scale or smaller scaled maps. I am not one to be nit-picky about travel times and having the hexes helps me take a look and throwing out a number for the players. No need for a ruler. Roll for a few encounters or have a few planned (which I usually do) and allow the players the option to get sidetracked (which they often do). It's critical that the game is not bogged down by calulations. Only delays should be the ones the players create themselves or it some how enhances the plot of the story.

Joseph said...

Horizontal hex maps are the work of Beelzebub himself. They are an unnatural blight upon the gaming and cartographic landscape and everyone who uses them should be buried alive with mice sewn into their mouths.

Vertical hex maps are the way nature intended such things to be done. Make your choice.

Not that I have a strong opinion about it one way or the other, of course...

Stephan Beal said...

Regarding submaps: i don't understand why the underlying scale of the smaller hexes has any direct effect on the placement of the superhex. The scale of the subhexes is arbitrary and imaginary - i can change it at any given time and that doesn't affect the placement of the surrounding superhex.

Stephan Beal said...

PS: @joseph: horizontal hexes are actually often better for on-screen play because screens almost always have dimensions which are wider than tall. By using horizontal maps we can stretch out more of the map on the screen (at least for wargaming maps, which often have some goal/target at one or two edges of the map).

1d30 said...

Also note that when playing with a hex mega-mat, some players will see the map from their perspective as horizontal, others as vertical. Unless you prohibit people from sittinf at the ends of the table.

imredave said...

Old school use of hex maps and the why. Back when I started playing wilderness games were usually done with a detailed map for the ref and a blank map for the players. It was pretty easy when the party moved into the next hex say this is a swamp hex and have the player mark with a swamp symbol rather trying to describe the size and shape of the swamp. For scaling up and down a square grid is a lot easier, so sometimes I would draw the thinking maps on square grids and then only do the final map on hexes. You do have to be more careful with square grids to avoid having terrain that looks like stair steps, hexes seem to hide the grid patern better.

Louis Zocchi said...

Horizontal and vertical maps have vital impact on how your road movements are shown. When designing a Gettysburg game, I used a vertical map because the Chambersburg Pike was depicted on a slanting row of hexes, which is what most of the Southern units arrived on. Most of the Union forces arrived on the Baltimore pike, which ran directly up the north south row of vertical map hexes. So when choosing which map layout is better, consider how many entry roads lay on hex rows which compliment the arrival of most of the forces.
Because Jeb Stuarts men arrived on a road which ran cross grain to Gettysburg, I had to bring him in on the map board one hour ahead of schedule, so that he could arrive in Gettysburg at the time he really got there. When moving cross grain, the counter goes through a full hex, than the edge of an adjoining hex, then a full hex, a hex edge, a full hex and a hex edge, etc. Because the edge of a hex does not cover the same distance as a full hex, there is a distortion of movement portrayal, which you can compensate for, by changing the arrival time so that it allows those units to be present at their historic destination, when they arrived according to history. The fact that they may not go to their historic destination, is not as valid a concern, as the fact that they could have arrived on time.
Louis Zocchi, Designer of Battle of Britain, Luftwaffe, the D-100 and co-designer of the GAMA award
winning D-total in 2009.

jlv61560 said...

As a long-time wargamer (going on 50 years now), the advantages of hexes for movement as compared to chess board like systems is fairly self evident. As a long time Fantasy RPGer (going on 40 years now), the biggest problem with hex maps is that no one ever came up with a way to use them very effectively to depict buildings at the micro-tactical scale. People tend to make those darn things at right angles, and hexes just don't work that way. It makes the whole visualization thing tougher -- which is why the whole hex-map system Metagaming came up with for The Fantasy Trip is so difficult for some people to wrap their heads around. (Disclaimer: TFT is my favorite Fantasy RPG by far TO THIS DAY -- it's just so much easier to use than anything else, with the possible exception of the whole building thing, though you should all check out Dark City Games' retroclone of TFT -- they've done some good mapping work). On the other hand, using hexes to map in something like, say, Judges' Guild's Campaign Mapping system could work even better if they'd just rationalize the hex sizes in alignment with one another. Why have half hexes, which leave lots of confusion in their wake, when you can just run the larger hex outline along the smaller hex borders? It doesn't distort the world view much, and it makes the entire terrain issue enormously simpler for the mapper. Now if I could just figure out an elegant way to do buildings.