Mappa Mundi [tutorial] - How to Clean Up a Map Using GIMP and Inkscape

The last week was horrendously stressful, a mix of the post-holiday blues, the rushing onset of back-to-work-after-three-weeks-of-BSing, and the shock to the system of the three senior NCOs above me having family emergencies and all pointing at me to take up the reigns. So on Friday morning I decided I needed to destress a little. What better way than a map for the hell of it?

Numerous folks have asked for a map making tutorial. This is not it.  :P

Sorry, not had the chance for this yet but I thought a sort of evolution of the process might be nice.

For nearly all my maps I start with either a blank piece of paper (as I will use here) or a piece of of graph paper. Here you can see the complete drawing of a map I made on Friday. In this case I used a crappy office dual tip sharpie. These suck, stay away from them. ( http://goo.gl/9tVzv ) Do not, under any circumstances, use these piece of crap markers for any sort of map making. The map making gods will come down and smite you.

Serious.

The next thing I do is scan the map in using my multipurpose scanner/copier/printer I bought a few years ago. $80, top notch Canon, but purchase your cartridges through Amazon and save like 90%. Printer makers are bandits, highway robbery I tell you.

Then I open the image in GIMP and use the Colors/Brightness-Contrast option to increase the Brightness and the Contrast, usually somewhere around 30 or 40 for each. See below for what I mean.

Here you can see the difference between the original and the cleaned up maps. When I use grid paper, this process reduces the strength of the grids to almost non-existence. I use a home-made graph paper that I made the lines very light to begin with so my normal process will almost completely remove the grid with little loss of the original image. In this example it is not 100% clear but you can see how the process lightens the lines, in some cases this is more of an art than a science and you have to play around to get the correct settings.

Now, looking at the above you might saw that the image on the right is faded, looks washed out. Correct, but it will work out fine for our purposes as Inskscape will detect the difference between the colors, in this case pure white and the washed out black. You must have some contrast here or this will not work. Sometimes you will need to tweak it a bit and play around to get the effect just right. Next thing I do is copy the image over to Inkscape. Here I utilize the Path/Trace Bitmap option as below:

This again is a bit of an artform and not a science. I change only one setting, the Brightness Cutoff Threshhold. Depending on the artwork, it tends to be somewhere between .5 and .85. Just depends on the piece and having the patience to try again until you get the image you want. I have played around with other options here, colors, grays, etc but just messing with the Brightness cutoff Threshold seems to do the trick perfect.

Once this is done, I copy back to GIMP and do any clean up I might need to do using a simple eraser tool. Occasionally paper imperfections, smudges or goofs (yeah, I make them all the time) need to be removed or tweaked at this step. It is best if you can remove these prior to importing into Inkscape so the overall effect of the trace is consistent throughout the entire image. Once you are done with that portion you are done!

Around here I usually add special stuff in like the key:

Or some fancy shmancy backgrounds:

Since all the tools I use are free, I figure anyone that has an opposable thumb and can use a mouse can probably pull this off. What are you waiting for? If you try your hand at this, let me know!

So there you go, I hope this helps any aspiring map makers. Enjoy, and happy mapping! 

I drew this map using a crappy dual tip Shaprie, on plain white copy paper. I make the map available here for personal use. If you write an alternate adventure or use the map in your game, on your blog, or what have you, please let me know. I would love to know! You cannot use it in any commercial or non-commercial product without my prior approval.