The folks over at the New York Public Library published an excellent & comprehensive tutorial for digitizing historical maps, and then importing them into Minecraft.

First: thank you!

Unfortunately, for me, it’s not working. I document here what I’ve been doing and ideally someone far more clever than me will figure out what needs to happen…

The first parts of the tutorial – working with QGIS & Inkscape – go very well (although there might be a problem with colours, but more on that anon). Let’s look at the python script for combining the elevation map (generated from QGIS) with the blocks map (generated from Inkscape). Oh, you also need to install imagemagick, which you then run from the command line, to convert SVG to TIF.

“The script for generating the worlds uses PIL to load the TIFF bitmaps into memory, and pymclevel to generate a Minecraft worlds, one block at a time. It’s run successfully on both Mac OS X and Linux.”

I’ve tried both Mac and Linux, with python installed, and PIL, and pymclevel. No joy (for the same reasons as for Windows, detailed below). Like most things computational, there are dependencies that we only uncover quite by accident…

Anyway, when you’ve got python installed on Windows, you can just type the python file name at the command prompt and you’re off. So I download pymclevel, unzip it, open a command prompt in that folder (shift + right click, ‘open command prompt here’), and type ‘setup.py’. Error message. Turns out, I need setuptools. Which I obtain from:

https://pypi.python.org/pypi/setuptools#windows-7-or-graphical-install

Download, install. Works. Ok, back to the pymclevel folder, setup.py, and new error message. Looks like I need something called ‘cython’.

http://cython.org/#download

I download, unzip, go to that folder, setup.py. Problem. Some file called ‘vcvarsall.bat’ is needed. Solution? Turns out I need to donwload Microsoft Visual Studio 10. Then, I needed to create an environment variable called ‘vs90comntools’, which I did by typing this at the command prompt:

set VS90COMNTOOLS=C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\Tools\

Wunderbar. I go back to the pymclevel folder, I run setup.py again, and hooray! It installs. I had PIL installed from a previous foray into things pythonesque, so at least I didn’t have to fight with that again.

I copy the generate_map.py script into notepad++, change the file names within it (so that it finds my own elevation.tif and features.tif files, which are called hogs-elevation.tif and hogs-features.tif; the area I’m looking at is the Hogsback Falls section of the Rideau. In the script, just change ‘fort-washington’ to ‘hogs’ or whatever your files are called). In my folder, at the command prompt, I type generate_map.py and get a whole bunch of error messages: various ‘yaml’ files can’t be found.

Did I mention PyYaml has to be installed? Fortunately, it has a windows installer.  Oh, and by the way – PyWin is also needed; I got that error message at one point (something obscure about win32api), and downloading/installing from here solved it: http://sourceforge.net/projects/pywin32/files/pywin32/

Ok, so where were we? Right, missing yaml files, like ‘minecraft.yaml’ and ‘classic.yaml’, and ‘indev.yaml’ and ‘pocket.yaml’. These files were there in the original repository, but for whatever, they didn’t install into the pymclevel that now lives in the Python directory. So I went to the pymclevel repo on github, copied-and-pasted the code into new documents in notepad++, saved them as thus:

c:\Python27\Lib\site-packages\pymclevel-0.1-py2.7-win32.egg\pymclevel\minecraft.yaml

Phew. Back to where I was working on my maps, and have my generate_map.py, which I duly enter and…. error. can’t find ‘tree import Tree, treeObjs’.  Googling around to solve this is a fool’s errand: ‘tree’ is such a common word, concept in programming that I just can’t figure out what’s going on here. So I turned that line off with a # in the code. Run it again…. and it seems to work (but is this the key glitch that kills all that follows?).

(update: as Jonathan Goodwin points out, ‘tree.py’ is there, in the NYPL repo

…so I uncommented out the line in generate_map.py, saved tree.py in the same directory, and ran the script again. Everything that follows still happens. So perhaps there’s something screwed-up with my map itself.)

The script tells me I need to tell it whether I’m creating a creative mode map or a survival mode:

so for creative mode: c:>generate_map.py map

for survival: c:>generate_map.py game

And it chugs along. All is good with the world. Then: error message. KeyError: 255 in line 241, block_id, block_data, depth = block_id_lookup[block_id]. This is the bit of code that tells the script how to map minecraft blocks to the colour scheme I used in Inkcraft to paint the information from the map into my features.tif. Thing is, I never used RGB R value of 255. Where’s it getting this from? I go back over my drawing, inspecting each element, trying to figure it out. All seems good with the drawing. So I just add this line to the code in the table:

block_id_lookup = {

[..existing code…]

255 : (m.Water.ID, 0, 1),

}

And run it again. Now it’s 254. And then 253. Then 249. 246. 244. 241. Now 238.

And which point, I say piss on this, and I provide you with my features tif and elevation tif and if you can please tell me what I’m doing wrong, I’d be ever so appreciative (and here’s the svg with the drawing layers, for good measure).

….when I first saw the tutorial from the NYPL, I figured, hey! I could use this with my students! I think not, at least, not yet.

(update 2: have downloaded the original map tifs that the NYPL folks used, and am running the script on them. So far, so good: which shows that, once all this stuff is installed, that it’s my maps that are the problem. This is good to know!)

Part Two:

(updated about 30 minutes after initial post) So after some to-and-fro on Twitter, we’ve got the tree.py problem sorted out. Thinking that it’s the maps where the problem is, I’ve opened the original Fort Washinton features.tif in MS Paint (which is really an underappreciated piece of software). I’ve zoomed in on some of the features, and compared the edges with my own map (similarly opened and zoomed upon). In my map, there are extremely faint colour differentations/gradations where blocks of colour meet. This, I think, is what has gone wrong. So, back to Inkscape I go…

Update the Third: looks like I made (another) silly error – big strip of white on the left hand side of my features.tif. So I’ve stripped that out. But I can’t seem to suss the pixel antialiasing issue. Grrrrr! Am now adding all of the pixels into the dictionary, thus:

lock_id_lookup = {
0 : (m.Grass.ID, None, 2),
10 : (m.Dirt.ID, 1, 1), # blockData 1 == grass can’t spread
11 : (m.Dirt.ID, 1, 1), # blockData 1 == grass can’t spread
12 : (m.Dirt.ID, 1, 1), # blockData 1 == grass can’t spread
14 : (m.Dirt.ID, 1, 1), # blockData 1 == grass can’t spread
16 : (m.Grass.ID, None, 2),
20 : (m.Grass.ID, None, 2),
30 : (m.Cobblestone.ID, None, 1),
40 : (m.StoneBricks.ID, None, 3),
200 : (m.Water.ID, 0, 2), # blockData 0 == normal state of water
210 : (m.WaterActive.ID, 0, 1),
220 : (m.Water.ID, 0, 1),
49 : (m.StoneBricks.ID, None, 3),
43 : (m.StoneBricks.ID, None, 3),
}

…there’s probably a far more elegant way of dealing with this. Rounding? Range lookup? I’m not v. python-able…

Update, 2.20pm: Ok. I can run the script on the Fort Washington maps and end up with a playable map (yay!). But my own maps continue to contain pixels of colours the script doesn’t want to play with. I suppose I could just add 255 lines worth, as above, but that seems silly. The imagemagick command, I’m told, works fine on a mac, but doesn’t seem to achieve anything on my PC. So something to look into (and perhaps try this http://www.graphicsmagick.org/ instead). In the meantime, I’ve opened the Fort Washington map in good ol’ Paint, grabbing snippets of the colours to paste into my own map (also open in Paint). Then, I use Paint’s tools to clean up the colour gradients at the edges on my map. In essence, I trace the outlines.

Then, I save, run the script and…… success!

I have a folder with everything I need (and you can have it, too.) I move it to

C:\Users\[me]\AppData\Roaming\.minecraft\saves and fire up the game:

Does it actually look like the Hogs’ Back to Dow’s Lake section of the Rideau Canal and the Rideau River? Well, not quite. Some issues with my basic elevation points. But – BUT! – the workflow works! So now to find some better maps and to start again…