Ok, so I just found that people tend to spend too much work on creating maps, and I think that if people from the community just spend less time creating maps, not only we could have more maps, but also see people invest in other stuff, like creating savegames with cities etc..
This tutorial is litteraly a recipe: there is no need to "try things out", or tweak anything, like grayscale. Just pick the place you want, and voila, you get your map ready to go.
The tools you need for this are the following:
- Octave (On linux just get it from the repositories, on windows, just go here
http://sourceforge.net/projects/octave/files/Octave%20Windows%20binaries/)
- Any image manipulation program to concatenate images together and save as .ppm, gimp is a good example. On linux, imagemagick (get it from the repo) could be easier (ill give the commands for it), but you can use gimp aswell.
Step 1 - Getting the raw data
First we need the raw elevation data. Go to
http://srtm.csi.cgiar.org/SELECTION/inputCoord.aspselect the tiles you want, on "Select File Format" choose "ArcInfo ASCII".
Download all your files to a folder, lets call it "simumap". Keep this folder on a path easy to access
Step 2 - After having all the files you want, extract all the .asc files to the "simumap" folder.
Step 4 - Download the file "srtm_process.m" from
https://app.box.com/s/0ke2obkt2cfdv0kkzjo1Step 3 - Open octave, and go to that folder using the 'cd' command
for example, if the folder is at "c:\users\x\simumap" then type
cd 'c:/users/x/simumap'
On linux is similar.
Step 4 - Open the file "srtm_process.m" and at the forth line, replace the filename of the file you want to process. Type it the same way as the one that's already there, i.e. without the extension.
Edit: Also set a maximum height for the map. Set the maximum height that you expect among all the tiles you got.Step 5 - On octave, simply type (and press enter)
srtm_process
It will open a progress bar (may take a while), and at the end you'll get a .png file with all the appropriate height-scaling for simutrans. The sea-level must be set on -10.
Step 6 - Repeat steps 4 and 5 for every file.
Step 7 - Now you have one high-res .png for each map tile. We just need to concatenate all of them in one big blobby-bloated-oversized-map. You can use gimp glue them all together, scale down if necessary, and export as .ppm. If you prefer to use command line on linux, just jump to step 8.
Step 8 (optional, only for linux users) - we can stay away from gimp, and do everything using imagemagick on command line. When dealing with large files its easier this way.
Lets imagine that our files are called 1.png, 2.png, 3.png and 4.png, and that we want to concatenate them like this:
[1 2]
[3 4]
then just type:
montage 1.png 2.png 3.png 4.png -mode Concatenate -tile 2x2 big_map.png
convert big_map.png big_map.ppm
convert big_map.ppm -resize 50% medium_map.ppm
convert big_map.ppm -resize 25% small_map.ppm
If the files are too large, and you just want down-scaled versions, perhaps it would be wise to downscale first, and concatenate afterwards.
Step 9 - MANDATORY - Import the .ppm in SimuTrans and have Phun!!
Hope this helps bringing more maps into the community!
Cheers!