Madison, WI is on an isthmus (a narrow strip of land, connecting two larger land areas). The lakes surrounding Madison are a huge part of the culture of this area. It's where we sail and swim in the summer and skate, cross-country ski, or ice fish in the winter. So, I wanted to make a bathymetric map.

There are some pretty cool versions of the Great Lakes online (and similar versions of Mendota & Monona) but they cost upwards of $100 for a small map and considerably more for a larger version!

I decided to go with a fairly minimalistic version using inexpensive materials. I made a few versions: colorful posterboard; mirror at the bottom; and brown craft paper.

Materials:

laser cutter or exacto knife
materials (paper, cardstock, plywood, acrylic, whatever suits your fancy)
Illustrator, or other vector editing software if you'd like to do a different map.

Included files:

mirror lakes version
6 layer paper version
version with bathymetry not split

Step 1: Design

If you're lucky, you'll be able to find a PDF (vector) bathymetric map that you can use the lines from directly. In my case, I could only find raster versions, so I traced the bathymetry in Illustrator, skipping a few lines. Once you've traced your lines, save a version with all of the bathymetry in tact. You'll need it later if you decide to do a different version.

To hand trace, use the pen tool (P). Click a starting point, then click and drag the next to create the right curves, keep going all the way around your lakes. You can go back and edit specific anchor points or handles (determine curves) with the direct selection tool (A) when you're finished.

For the craft paper and posterboard versions, I used 6 sheets with each outline on a new sheet. I went ahead and had the laser cutter cut a box around my paper, rather than rely on the size of my paper, because I wanted to make sure that they were lined up perfectly.

The mirror lakes version was a little different. I wanted mirror at the bottom of all of the lakes, but I could only find a small piece of acrylic mirror in the trash (and didn't want to buy any), so I cut the same thickness acrylic in a different color, as normal, then cut the lake pieces on acrylic mirror. I fit the mirror into the white acrylic holes and glued both to a cardstock backing. See annotated image.

Step 2: Laser Cut It!

This cut super fast! I used 100% power, 20% speed for poster board and a little slower for the acrylic, but that's highly dependent on your laser cutter.

TIP: If you're laser cutting acrylic, keep the backing on, because it'll help keep your acrylic from burning. This is especially important for the acrylic mirror. If the backing is already off of the mirror acrylic, cover the mirror side with paper or painter's tape before cutting and peel off after.

Step 3: Put It All Together!

Glue those layers together!

For the paper versions, I used paper cement. For the acrylic version, I used contact cement (which is super smelly). Paper cement is really nice because the excess peels off really easily. You can use a kneaded eraser to facilitate getting off any marks or fingerprints from the paper. Follow the instructions on your glue of choice.

Bonus idea:

Instead of gluing your map together, you punch holes in the side, and clip together with loose leaf ring clips to make a book. You could annotate in hidden parts of each layer. (This would make a super cool kid's book if you made it out of hefty material!)

Extra Bonus:

Keep the largest lake pieces and attach to cork board!