Saturday, October 9, 2010

GIMP and the T map

A while back I downloaded GIMP, the GNU Image Manipulation Program. It's a powerful raster graphics editor - not quite as powerful as Photoshop, but way better than Paint. It's also free, open source, and runs excellently in Windows.

So far, I've mainly been using it for maps. I took a medium-quality scan of a Boston T map (with a few changes from the current service) that was a .jpg - a lossy format that doesn't save all image information. I changed it to a .png - a non-lossy format - and I've been modifying it.

First, I took all the water regions. I sharpened the edges and made them a uniform shade of blue with no bad pixels. Then I did the same to the land. It's really easy - just create a polygonal shape, pick a color, drop paint. Repeat.

The final, lengthy step is the subway lines. Erase the weird additions, and the bus routes, and the station names, and the highways, and all that. Reroute a few lines. Then, turn the mottled lines into straighter, blank lines, and I'll have a beautiful, high-quality blank map showing just the subway lines and the urban commuter rail stations.

Then, to have an actual functional map, I'll need to add in station names, stuff like that.

Finally, I plan to make modified versions of the map for proposed changes like the Green Line extension into Somerville. Much like this which is done by some guy who makes incredible maps, and has incredibly cool plans for subway systems.

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