Re: help: artist needs suggestions for globe

In article <4ozef.9105$2y.4491@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
"Mac" <marmac2@xxxxxxxxxxxxxxxxxxxx> wrote:

> Hello,
> I've spent the last three months building a 23" diameter sphere out of
> cherry using nothing but my tablesaw, jig saw, and sander. The next step is
> to carve the major (and some minor) land masses into its surface. I thought
> an interrupted sinusoidal map would do the trick, simply cutting it out and
> laying it onto the surface of the sphere for marking. However, the lobes of
> the map are not straight-edged. Meaning, when the map closes around the
> sphere, the lobes will not meet edge to edge.
> I know very little about cartography, obviously, and would appreciate any
> suggestions. If you would like to see the sphere, just go to:
> http://www.studio407.net/the_war_of_the_world.htm
> Thanks very much,
> -Mac

Mac:

There is very little in the literature about projections for globes.
Sinusoidal is a good first approximation, but the real problem is that
the optimal projection varies according to the characteristics of the
medium you choose to print the gores on. Different papers deform
differently when plastered to a globe.

My own studies of real globe gores show them to differ considerably in
projection, and usually based on unidentifiable projections. To start
with I recommend the rectangular polyconic with the standard parallel
set to the equator. The reasons are: (a) the parallels meet the
meridians at right angles, so no kinks develop between sections; (b)
parallels are spaced constantly along the meridians, as they are on the
globe; and (c) the shape of the gore generally edge-matches better than
sinusoidal and other pseudocylindric alternatives for most choices of
medium.

You can achieve a wide variety of gore shapes comparatively easily by
using the transverse aspect of many projections. With experimentation
you should be able to find one that suits your paper.

Regards,
daan Strebe

http://www.mapthematics.com/
.

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