Wednesday, May 23, 2012

Carving Countries

After finishing up the fiberglass sphere that will become the globe, we are almost ready to start carving countries.

First two sections of the Arctic ocean
The first step was to trace out a grid.  With the help of a protractor and flexible plastic spline, I drew lines every 15 degrees latitude and 10 degrees longitude.  These lines every 10 degrees longitude correspond to the edges between the 36 gores on the map I am using as a template.

Each cell of this grid becomes one section that will be carved out of wood veneer.  I bought an assortment of domestic and exotic wood veneers which provide ample selection for coloring the countries.  I also bought sequence-matched white oak for the water.

Tracing countries
The general process for a given cell is to use carbon paper to trace out the largest piece of country in that cell onto the selected piece of wood veneer.

Using a rotary tool, carve out the shape of that piece.  This then serves as an edge guide when tracing the next piece in the cell.  Small errors accumulate and result in subtle shifts of various borders; hopefully nobody notices.

The carved pieces are glued to each other, and then once a cell is complete it is glued onto the sphere.With time and patience you slowly get something that becomes recognizable.

Wooden Globe, North Pole Wooden Globe, North Pole Wooden Globe, Arctic Circle

These pictures represent approximately two years of work. The final picture below is the current state of the globe as it sits in my basement.
Wooden globe, Europe and Northern Africa
Not quite half finished

In retrospect, I am not entirely happy with my choice of woods on some of the countries.  For example, Britain really should be a darker color to contrast more with the ocean.  I find the striped veneer used on France and Poland tends to clutter Europe a little and a solid color would have been better there.  The stripes in Sudan really should have been aligned between the two cells.  However, due to the time invested here, I'm not inclined to go back and attempt to redo these pieces.

Hopefully the southern hemisphere won't take as long.  The hardest part is done, however all the islands in the south pacific will present their own special challenge.

Thursday, April 26, 2012

Wooden Globe, fiberglass edition

So I decided to build a globe.  After figuring out the maps, the next step was working out the structure of the globe itself.  My general plan is to glue wood veneer onto the surface of a sphere, so obviously the first thing I need is a reasonably sized sphere.  I wanted my globe to be relatively large, on the order of 16 to 18 inches in diameter.

My first thought was a sphere made of wood.  It turns out that making a wooden sphere of this size is an art in itself.  While you may be able to buy a wooden sphere, a large one wouldn't be cheap.  I considered plastic,  but was worried about how glue would work on that kind of surface.

I eventually decided to make a sphere myself using fiberglass.  So I went down to the toy store, bought a 16" diameter red rubber ball, and covered it in fiberglass cloth and epoxy resin with a structural filler.

The ball had Spider-man on it.

To support the globe, I bought bearings and a 3/8" brass rod.  I cut the globe in half and removed the remnants of the rubber ball.  Then I mounted the bearings in blocks of wood at the north and south poles. 

Spider-man left his mark.
North pole is at the bottom of the photo.

The bearing at the north pole is entirely internal to the globe.  The bearing at the south pole where the supporting rod enters will be the only opening in the globe.  Gluing the halves back together with some more epoxy and filler leaves us with a sphere free to rotate on its axis.

Tuesday, April 17, 2012

The start of making a wooden globe

I always liked globes. A few years ago I got the idea to make one out of wood and I actually started this as a project. Now I'm making a belated attempt at documenting some of this process.

Making a globe has to start with a map.  The best source I had for this was Google Maps, so I painstakingly took screenshots and merged them together to create a map of the world.

Google Maps uses a Mercator projection.  Before it can be useful as a template for making a globe, it needs to be massaged into a shape that we can trace onto a sphere.

A gore is a segment of a three-dimensional shape fabricated from a two-dimensional material.  We need to transform this Google map to look something more like this:

The gores of Waldseemüller's 1509 globe of the world

First, transform to a equirectangular projection.  I did this using a photoshop plugin called Flexify 2 which I was able to get to run under GIMP.

I found a page which has a satellite image of earth with 12 gores (as well as images for other planets), but I want political boundaries for my globe so this doesn't help.  However, that page also has a link to a perl script which can transform an image into gores.  I used this perl script to generate a map with  36 gores.

With some careful scaling, this can then be printed and traced onto the surface of a sphere using carbon paper.