Cartographic ethics: Oceania, the truncated continent
I recently came across an older feature in the Washington Post titled “These are the cities that climate change will hit first.” Citing the concept of climate departure, the article used world cities as a proxy to illustrate the impacts of climate change on the world. So far so bad, but the interactive map that came with the article had one irritating, if not to say infuriating problem: it cuts out exactly these parts of the world that are arguably most affected by climate change — the 20.000–30.000 pacific islands, atolls, archipelagos, and micro-nations. The effects of sea-level rise already manifest in a mounting refugee stream from sinking Micronesian islands to Hawaii and the Mainland US.
We divide the world neatly into seven continents, but the classification of the pacific islands remains ambiguous. Some islands are part of the Americas, others of Eurasia, but the largest part, Oceania is commonly grouped with the Australian landmass. Oceania is mostly an invisible continent: its islands, islets, and atolls being too small to be printed on most world maps. On the outer fringes of most world maps, its territories are cropped or covered by a legend. With of our example, the world ends just after New Zealand, and the legend covers eastern parts of French Polynesia.
The thoughtless use of Mercator projections in world maps is generally frowned upon, but truncating the lobes of projections such as Mollweide and Robinson is just as bad. But even without such mistakes, all political maps struggle with a conflict of intent: on the one hand, accurate representation of territory, on the other hand, the appropriate representation of populations.
To get a better picture of Oceania, I made a simple map of all named islands and atolls, described in the remainder of this post.
For this purpose, I used the global place-name database from geonames.org. Excluding the western parts such as the Indonesian islands and the Philippines, the data set contained about 8000 named islands.
Most map projections make it difficult to visualize the extent of Oceania since the pacific is usually cut in half. The azimuthal equidistant projection of the UN logo does a good job conveying the size of Oceania, especially when compared to what we hyperbolically call the “Western Hemisphere” — Europe and the Americas. The UN logo also shows an effort to include smaller islands; but nevertheless, the upper left quadrant appears mostly empty.
I used a similar azimuthal equidistant projection centered on the middle of the Pacific, plotting the 8000 islands as dots of equal size to get a better sense of their geographic distribution. Note that in this projection, distances from the center are preserved, but tangential distances on the fringes, e.g. between Galapagos & Easter island are exaggerated.
Inserted into the projection of the UN logo, the pacific islands appear like this:
And finally, the same projection centered on 0,0:
Of course, many islands are tiny and uninhabited. Kanton Island, a small atoll in Kiribati and the only inhabited island in the phoenix island group, has according to Wikipedia currently around 40 inhabitants.
