NewbieDM Tutorial: The Battlemap, a guest post by Jonathan Roberts

Posted on November 9, 2009 by


With this website, I’ve tried to give new DM’s out there tools, resources, and tips to run a better D&D game with.  One of the things that I’ve never been able to offer before today, simply because I have no skills at it, is a robust mapping tutorial or series.  So I reached out to the community at Cartographer’s Guild, probably the best mapping resource on the internet, and immediately I had a volunteer willing to help out readers with their rpg mapping.

Jonathan Roberts, a published cartographer who has done work for Mongoose Publishing, Kobold Quarterly, Open Design, and other publishers, has graciously accepted to provide us with a series on mapping.  Jonathan has a website called Fantastic Maps, where you can see his work.  He is also the project lead on the first Pathfinder adventure to be purposefully created for use with virtual tabletops: “The Breaking of Forstor Nagar”. You can find information on that patronage project here, and find screenshots of the project here.

Over the course of the next few weeks, he’s going to give us tutorials on creating battlemaps, regional maps, and world maps.   And these are not just tutorials on how to draw the maps, but also the thinking behind why things go where they do.  I’m excited to present this series, and I hope these tutorials help you out in what’s probably one of the funnest part of DM’ing, great map-making!  And now, Jonathan Roberts…

Designing and drawing a battlemap – part 1

“Through the archway you see a circular room, roughly 20 feet across, with doors leading off to the east, west and south. The ceiling looks to be vaulted, but it’s hard to tell due to the thick mass of cobwebs that hang like ghostly shrouds. A pile of bones lies heaped in the corner.”

It used to be the case that a DM could describe a dungeon to their
players and everyone would know what was going on. If necessary
players would draw out a map on squared paper as they went along and if a fight broke out the terrain would be built out of pencils and erasers with dice standing in for the combatants. Now this is fine as long as all rooms are built in clean 10 foot squares, but time has moved on and the game has evolved. Adventures take place in the intestines of petrified wyrms, or on the deck of a storm tossed ship. Combat rules have become more involved, requiring careful tracking of distance and terrain. Thankfully the tools we use to play the game have evolved too, whether it’s in the form of dungeon tiles, virtual tabletop software or just a dry erase mat with a grid drawn on it. The adventures that are published have also moved on. Where in the past it was fine to have black and white maps (or blue and white if we’re going really far back) with distance measured in 10 foot squares, now published adventures have glorious full colour maps.

So what do you do when you need a map for your home brew
adventures? There are two things to consider when answering this.
Firstly how do you go about designing the map, and secondly how will you present it? All too often the second question influences the first. If you have a selection of dungeon tiles that you use to display your maps then you can easily fall into the habit of creating maps by taking out your tiles and figuring out the layout of the dungeon. If you use virtual tabletop software you might feel even more limited – only running adventures using maps that you can find or buy through the internet.

Now these are both great ways to create dungeons, particularly when pressed for time, but I’m going to show you how to go about making maps from scratch that look great.  Not only that but I’ll also cover a couple of different methods that will allow you to use these in front of your players, so that you’re not the only one that gets to see the fruits of your labour.

Here’s the map that I’ll be creating in this tutorial:


The full sized version, along with two maptool campaign files, a sliced up pdf for printing at home and a number of pieces of set dressing can be picked on RPGNow.  Now as a special treat for all you NewbieDM readers, there’s a discount code so it’ll only cost you a dollar.

First of all, let’s discuss tools. For this tutorial I’ll be using Gimp – a free, cross platform and open source graphics program. Now if you have a graphics tablet that’s a huge bonus, but the majority of what I cover in this tutorial will be possible with a mouse. All of the steps that I cover here can be directly translated into photoshop.

So shall we start drawing?

Well, not quite. As I said before, there are two questions about maps-first how we should design them, and secondly how they should be presented. So let’s start off with design questions before we put pen to paper.  In this tutorial we’ll be doing battlemaps.

These are fundamentally tied to combat and should be designed with this in mind.  You need to think what kind of encounters you want to throw at your players.  Do you want to give the ranged PCs an encounter where they can fire across large open spaces?  Would you prefer a tight corridor where the fighter can hold off the hordes?  Will the combat change halfway through when enemy reinforcements surprise the PCs from behind?  If so then you’re going to want to make sure that there’s a passageway they can appear from.  The art of designing a good encounter has become more sophisticated as the game has evolved, and the current manuals have excellent advice on how to build a good combat.  Now remember, it’s easier to change the encounter than the map, so best nail down the encounters first.  Then you can build the map you need to run them.

In this tutorial I want to create a lair for a young adult red dragon.  Dragons love caves, and they also love treasure.  However I don’t want this to be a straight forward single monster encounter – it would be fun to have some smaller enemies to fight as well as the dragon itself.  So let’s say that the dragon has acquired a tribe of humanoids that provide it with sacrifices and treasure.  Not only do they add an excellent lesser
threat for the players, it plays to the themes of vanity and greed that define dragons as well as giving me a couple of hooks to get the players involved.

This mix of foes means we should get a good mix of mass combat encounters and fights with a single monster.  I want the dragon to have opportunities to outmaneuver the PCs. The easiest way to do this is to have the dragon flying.  Now that’s not much of a benefit if the whole dungeon is flat, so let’s have some rooms with high ceilings and different levels inside.  Whilst the players are slogging across the difficult terrain the dragon can be swooping back and forth.  Perhaps we’ll throw in some lava as well to give the encounters some added danger.  Nothing says epic battle like the chance of falling into lava.

I want the fight with the dragon to have a number of beats.  First the players will encounter the dragon when he is about to devour a sacrifice.  They will battle through the dragon’s acolytes to get to the sacrifice and fend off the dragon whilst they whisk the prisoner out of harm’s way.   Then they will go after the dragon – first fighting the dragon in the outer  caves.  They wound the dragon badly enough for it to retreat.  They can leave it at that and go home, or they can follow the dragon to it’s hoard.

There it will fight to the death in a climactic battle – probably with more lava. So I want to have three primary locations. Firstly the outer area where the sacrifice is made. Second the tunnels to the dragons lair where they fight a running skirmish and encounter the dragon’s traps.  Finally the dragon’s hoard where they fight to the death.  Now we have the required locations, and we know the type of fight we’ll be running in each place it’s time to pick up a pen and draw a sketch!

Drawing a sketch

First off let’s lay down a sketch of what we want the location to look like.  Open up a new document in Gimp and set the dimensions to 2000px to a side.  Here’s my layout whilst I’m working – it’s easy enough to set up:


If you don’t have the layers dialogue open, you can find it under Windows->Dockable dialogues, along with the other dialogues.  First of all let’s lay down a grid for us to work with. First create a new
layer (ctrl-shift-n) and make sure it’s transparent. Then go to Filters->Render->Pattern->Grid.  Set the offset to 0 and the size to 50px.

This will create a map that’s got a resolution of 50px per square.  This is good enough for use in a virtual tabletop but if you’re going to be printing then you probably want to go for 100px here.  Now you can go larger.  Print images are normally printed at 300px per inch, but you’ll find that Gimp will start eating up your system’s memory. Anyway, how finely detailed do you need a battlemap to be? I find that 100px per grid square (remember that when printed 1 grid square = 1 inch) is a good compromise.

Rename that layer to Grid – we’ll be using quite a few layers and its always worth naming them to keep track of what’s what.  We’ll be leaving our Grid layer alone for now.  Now let’s sketch out our map.  First create a new transparent layer (ctrlshift-n) and rename it Sketch lines.

At this point I have a layers dialogue that looks like this:


Make sure that when you are working on your map that you have the correct layer selected.  There’s nothing more irritating than finding you’ve been working on the wrong layer and having to do it all over again.

You can fit the whole map to your screen using ctrl-shift-e so that you can see what you’re doing.  Now take any of the tools and start sketching in lines.  I like using a colour and the ink tool. This delivers nice clean lines.  Now start at the beginning, by drawing the entrance to your dungeon.  Lay out corridors and rooms, remembering your notes about what each encounter area needs to achieve.

An aside about adventure flow

Remember that your map defines the flow of an adventure.  A map that has a series of rooms with one entrance and one exit will lead to a linear adventure as players fight through room after room.  This lends itself to dull adventures where players can feel railroaded.  On the other hand, a maze where every turn offers three or four possible directions can leave players feeling lost and unsure that they’re going the right way.  Think of each room as a decision in the adventure. Players need to choose which exit to go through to get to their goal.  Just as you should offer players more than one way to solve a puzzle, it can be useful to offer players more than one path that they can take through a dungeon.

Back to the sketch


So, following my plan to have a big encounter in a cavern with a tribe and a sacrifice, I’ve laid out a room with a series of terraces at the front that overlooks a cave with the sacrifice platform on top of a pillar. A rope bridge will connect the two areas over the floor below. This area is around 100′ by 80′ in size, offering plenty of space for combat. The terraced seating lends a ghoulish feel to the sacrificial process. The rope bridge, pillars and long drop to the floor ensure that the dragon will have a solid advantage… and if he decides to destroy the rope bridge while the adventurers are on the pillar rescuing the sacrifice then that’s
just icing on the cake.

A couple of passages lead deeper into the mountain. The players can choose either one – they’ll both lead to the same place eventually. The twisting caves offer lots of opportunities for the dragon to circle around
and attack from unexpected directions, and the tight quarters are perfect for placing rock fall traps and pits.

Finally I place the dragon’s lair – a good sized cave enough room to maneuver, but without the large amount of space of the first fight. I want the final fight to be a toe to toe melee combat with the dragon where it can use all of its attacks in contrast to the skirmishes and strafing runs of the earlier encounters. Even though they fight the dragon three times, they should have three very different encounters.

The dragon has his own entrance that I’ll place much higher up the mountain side. Observant adventurers might spot it, and athletic ones might be able to climb the icy cliffs to get in this way. However if they
infiltrate the dungeon through this entrance, they’ll not be able to save the sacrifice in time.

So that’s the logic behind my decisions. Make sure you follow your own logic as you place your own sketch. If you get the layout right now it will make life much easier further down the road. I’m sure you can all see an obvious error my layout so far. I didn’t spot it until the next step…

Laying in the lines

Once you have your dungeon drawn in rough it’s time to start a final version. At this point I create a new (transparent) layer (ctrl-shift-n). This will hold the walls that define areas the PCs can’t enter and other key
structural features like stairs, edges of elevated areas, that sort of thing.  When working on this layer I zoom in to 100% and set the sketch layer to 50% opacity (using the opacity slider in the layers dialogue). Now you can see where I made a few edits to my original layout. I’ve also resized the image up so that my squares are 100px each as I want to allow people to print this out, as well as use it online.


Now it’s important that your walls don’t have holes in them. You’ll see why in the next step.  Be careful as you lay them down, and if your dungeon is rough stone, let your hand jitter around as you draw, this will
create nice rough edges. If your walls are straight then click once at the beginning of the line, then hold shift and click at the end of the line.  Voila! A straight wall.

Equally, it’s easy to create curved lines. Just take the elliptical selection tool (e) and drag out a selection corresponding to your pillar or post (holding down ctrl, shift or alt all help to constrain your ellipse in different ways – have a play and see what works). Once you have the selection you want, go to Edit->Stroke Selection and pick a nice thin line like 2px. Hit okay and you now have a lovely round pillar.

If you’re not sure something will work, try it on a new layer. Then once you have the lines you want, right click the layer in the layers dialogue and select Merge Down to combine it with the rest of your lines.

The Best Bit

Now we’re going to employ one of the most powerful features of Gimp.  Take the fuzzy select tool (u) and make sure that you have your Lines layer selected. Click in the area that you want to be solid wall. Then hold down shift and click in the next region that’s solid wall.  Repeat until all such areas are selected.  You should now see something like the image below.  Make sure that it has selected only the regions you want it to.  This is where all the care you took over your walls pays off.


Now currently your selection (the line of marching ants) will run alongside the lines you drew rather than down the middle of them.  To fix this go to Select->Grow… and pick 2 pixels as the value.  Now your
marching ants should run pretty much down the middle of your line.  We’ll be using this selection a lot so we’d better save it by going to Select->Save to Channel…

If you have the Channels dialogue open you’ll see a new channel appear under Red, Green, Blue and Alpha Channels.  Rename this to Walls and head back to your layers dialogue.  Now that you have this selection the majority of the work is done! From here on it’s surprisingly easy to get a good looking map. Indeed we can get a great simple map with just one more step. Go to your grid layer in the layers dialogue and right click. In that menu find the option Add Layer Mask and when prompted pick the option Initialise Layer Mask to:  Channel.  In the channel you’ll see the shape of your walls already mapped out. Now what this is going to do is hide any of the grid that’s in an area that wasn’t inside the selection that you saved.

Now obviously this is the opposite of what you want. You selected all the walls, and you want the grid to be hidden there and visible everywhere else, so click the Invert checkbox.  Hit okay and you’ll see the grid disappear in the walled off areas. Delete your sketch layer and you now have a lovely clean battlemap!


Now this is a great map to use for a battlemap. It doesn’t take too longto create, it’s all at the right scale and all the features are clearly shown.  You can print this out without killing your printer’s ink cartridge and it can be easily imported into your virtual tabletop of choice. Save it! First save it as a .xcf file (Gimp’s native file format that preserves all of the information) and then save it out as a jpg.

And just to show how cool your work looks – here it is in maptool:


However, some people prefer their maps with a bit more pizaz so in the next installment I’ll show you how to go about adding some colour…

And there’s the first part of the Battlemap tutorial.  I want to thank Jonathan for helping me with this series, and I hope readers get some nice use out of it.  Stay tuned, as in the next several days we’ll have part 2 up and ready for you guys to keep building your map with.  Also, please make sure you visit Jonathan’s online store and see what kind of maps he’s got for sale.

Edit:  Here is part 2 of the tutorial