Mount Tamalpais Topographic Map (and candle side project)


I made a topo map of Mt. Tam, just north of San Francisco, as a housewarming present. The hardest part of this project was getting the topo cut lines that I needed. Ultimately I learned just enough QGIS to extract the contours from the USGS data. I wish that was easier.

The material is cherry plywood and the frame is one layer of black acrylic glued to several layers of draftboard to get the required depth.

I ran through several prototypes. The first was at a smaller scale and wasn’t very impressive.

I then doubled the scale to 1"=1,200 feet and built a good prototype out of draftboard. I used the “cut every other contour” method to reduce the materials used, though I hadn’t yet figured out the tip that you can score the contours that you don’t cut in order to create a gluing guide. It takes about an hour to glue all the layers together.

The hollow prototype got me thinking that I could use it as a mold to create some version of this model more quickly. After some fits and starts I made a form that I used to create a mold from silicone and corn starch, and I’ve been using it to create three-wick candles of Mt. Tam quickly and easily.

For the final topo map I added a score line for the main road up Mt. Tam then cut two sheets of cherry plywood. I alternated the cut and the score lines for the topo contours, which made the gluing stage much more accurate. I carefully glued the layers together, using office binder clips as clamps when necessary.

On the underside I shot a few lines of hot glue gun (they look silver in this photo) to add some strength, and I reinforced the edges that didn’t quite reach sea level with some columns of square draftboard so I could mount the model to the base more securely.

I’m not thrilled with the frame - I probably should have made my model a bit smaller because I didn’t have a big enough print bed to cut complete rectangles for the frame, so I had to cut draftboard in 0.5" strips and glue them together, about 2.5" high.

I then cut the top layer of the frame from black acrylic and scored the captions, which I then filled with white paint so they’d stand out more. Again, I wish I’d left enough room to do this seamlessly but I had to do it it pieces because the main model was almost the size of my print bed.

I learned a lot from doing this project and although it was pretty time consuming I think I could work more quickly on projects like this in the future, especially if I get better at using QGIS to extract the contour lines.

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Oh that candle mold is clever. Nicely done.

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Re: the candle - I had some setbacks along the way.

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Love me some topo maps. The candle mold is pretty cool too.

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What a welcome gift for a new homeowner this will be - but I bet they will have no idea how much effort went in to creating this piece of art. I hope you don’t stay away from posting in the forum for another year again.

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Really nicely done. I know the area (my son lives near there). The candle mold was a really clever extension of the project. The gluing pads underneath was a really good idea too. The build-up of the frame kind of evokes the steps of the topo lines. Seems to fit in thematically very nicely.

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This is a nice gift. Looks like a lot of work!

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Oh wow, well done!

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Did you look at using GeoPDF’s that have the contour lines? Assume since you used QGIS that you generated them from a DEM.

NIce work and great ideas! The person getting that will be thrilled. And the candle is a super idea!

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Oh wow, how cool is that!?! That’s got to be one of the coolest candles around.

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What an impressive gift! Love the candle!