One of my absolute favorite scenes from The West Wing (one of my favorite shows) wasn't about politics, or war, or even the President. Instead, it was a quirky plea to change the default map projection used when teaching children about the world. For your amusement, here's the clip...
sorry - clip has been removed from YouTube. I'm sure you can search and find the West Wing clip about map projections with little effort...
sorry - clip has been removed from YouTube. I'm sure you can search and find the West Wing clip about map projections with little effort...
For the curious, some more details about the Gall-Peters projection!
Map projection isn't just a concern for cartographers, city planners, or ocean travelers. Astronomers deal with maps all the time as well! (Sometimes we astronomers forget this.) For example: one of my absolute favorite graphs from the last decade in astronomy comes from the SDSS, and is titled the "Field of Streams"...
Credit: Vasily Belokurov, SDSS-II Collaboration |
So let's playfully extend the logic from the West Wing. If using traditional Earthly map projection can lead to generations of international strife, then our concern for heavenly projections should be far greater! Consider the interstellar politics at play, and the need to avoid a false sense of Orion-Imperialism. I hereby create the Organization of Astronomers for Celestial Equality (OACE - now accepting membership applications).
Let us consider, what does your Galaxy really look like?
For this example, I've grabbed 2.5 million random stars from 2MASS, a famous infrared all-sky survey. Here is a density map of the Milky Way (from our vantage point) in the most basic map projection: uniform steps in latitude and longitude.
Here is the same data in a handful of other projections...
Sinusoidal |
Robinson |
Mercator |
Hammer |
and my personal favorite of the set...
Goode Homolosine |
Look at how far the LMC and SMC appear to move between projections! What do you think, which is the best projection? Which is the most accurate for astronomy?