Big Data and Small Details

I’ve been exploring the wonderful world of open data, and have found that most cities offer up files with surprising levels of detail. Not all of these files are created equally though, and almost none are the .SVG that we know and love here. This particular project started as three shape files (.SHP) from OpenDataPhilly.

Taking a shape file and converting to a .SVG is a fairly straightforward process. This method will get you an .SVG that etches nicely onto a surface, but I wanted to cut mine out instead.

To groom the resulting .SVG, I thickened all the strokes to ~200%. I did this to maintain the relative thickness differences between highways, arterial streets, and capillary streets. I then converted strokes to paths and made the new strokes (which outlined the boundary of the original stroke) 0.1 mm thick. Now I had streets that connected the entire map bounded by very thin strokes to cut.

If this method doesn’t provide good results, then scale up your map ~10,000%, use the inset path function several times, and scale it back down. Scaling the project up will prevent goofy rounding errors like the ones you see on the inner rings of these figures. With the fine details of these maps, you want to maintain the straight lines as much as possible!

But why bother with open data and .SHP’s when I could go use the dummyproof Snazzymaps Template to get an .SVG right away??? The reason is that I am not just after the map, I am after a STORY. Combining this map with other layers of data like neighborhoods (red) or water features (blue) gives an interesting narrative the City of Brotherly Love.

This example isn’t as strong as I would like, but I plan to delve into other more provocative topics like crime, property value, litter density, and income. These data sets are all publicly available and unsurprisingly make nice contour lines akin to a topographic map. I hope to revisit this soon!


Openstreetmap lets you export maps as SVGs, for future reference.


Thanks for the tip! I didn’t go with that route here because then I’m limited to the data available in openstreetmap. For vital data like the locations of Big Belly Waste Bins I would still need to go through the conversion process.

Using the Google Map Styler has been useful for some of my other projects though. It’s a lot easier to define the stroke for highways via the map style than it is to select the pieces of all highways in inkscape, for example.


You can use “select same…” to great effect here. Chooe a highway, then right click on it to select same. Play with the options, I bet you can get all your highways in one shot.


The delicacy and clarity of that cut is frickin’ impressive!


Thanks! The data I drew from is actually even more detailed, but I used Tilemill to filter out all the super short lines. I plan to cut on two sheets of 12x20 with the river separating them - eager to see how much detail the large format can cram in!

Download and try QGIS, its free, but donations fund development.

GIS software allows you to select lines, points and polygons by using their Attribute Table entries / values. An extremely powerful tool.

QGIS also allow the creation of custom maps and then converts SHP files to SVG. Very good converter.


Shame on me, I said I used Tilemill to remove short lines but I actually used QGIS! I believe step 3 of this tutorial is the process I used. Either way I appreciate the pointer, it helps me remember the process for when I get back to this project!

Edit: HOLY COW! I just saw your work at and it’s excellent! You’ll probably see a few purchases from me - $4 is worth saving an hour or two even if I end up layering more data before I finish.


I am only distributing the data as a single download, all World and state files, it is over a gig of data. Also, it does not have the detail of the data you used to produce the maps in this thread.


I’m really impressed that those little pieces didn’t burn up.


Wow! Great work. A ton of great information in this thread. I’ve been messing around with Snazzy Maps for a bit now, but haven’t made anything yet. I made a style that I like, I just have no idea how to share it.

Now I have to go down the rabbit hole of QGIS. Thanks guys. :stuck_out_tongue_winking_eye:



That looks like a perfect template! If you do cut it out, here are some general tips:

  1. Slower cuts with less power for paper! The laser will naturally slow around corners, so a high-speed high-power run will usually char at the corners. Less char, less discoloration, more precision, and an overall better product with slower cuts.
  2. I recommend making two ladder-like test files. On the first ladder, make the “rungs” incrementally thinner. I found that the forge was precise enough to cut very narrow lines, but aesthetically those wisps of paper didn’t contribute to the design (IMO). I made sure my streets were wide enough to avoid this. On the second ladder, make the “rungs” incrementally closer to one another. This will let you gauge the return on investment for the super small cutouts. I used QGIS filtering to remove all paths that were (IMO) too short to be worth the cut.
  3. If you’re cutting a lot of little pieces, be prepared for confetti! A single stray paper scrap can ruin an hour of cutting time. Investing in a Seklema mat or making your own with repositionable adhesive and a solid base will prevent despair.
  4. “Floating” items. I’ll assume you will use a solid blue piece of paper as your base layer. For “floating” items like the islands on the right of your design, etching an inset outline of their position helps to place them when you assemble the end product. You can’t see it on my picture, but everywhere a road crossed the river I etched a thin line to ensure the layers matched up.

Hope these help! Cheers!


THIS! Engraving takes way longer but completely removes this issue


Thank you for the tips!

My current plan was to make it with wood. I was planning on engraving the water, then cutting out the streets from a separate sheet (maybe acrylic) and gluing it to the top. I was considering adding text as well, but we’ll see.


You’re a master data wrangler now. I’d love to see how you decide to display different types of data. Please keep us posted!


Last night was my first opportunity to zap a test file, so I haven’t removed the paper masking or layered any data yet. As always, I’m blown away by the precision of the 'forge. These streets are ~0.5mm thick.

Hoping to take time to cut a few data layers of data tonight on bright cardstock. Wish me luck!


Follow-up to this thread at Laser Maps for Family. Stay tuned if you’re interested in tutorials / lessons learned!