It's the legacy of the national surveying system begun by the Land Ordinance of 1785. [0]
Except for the thirteen original states, almost the entire country was surveyed and platted into square "townships" [1] of six miles a side. These were subdivided into square-mile "sections", and roads were built along section lines. Where there were no major rivers, towns were generally established at the intersections of these roads.
For more historical color (and stereotypes), try "Why the Midwest is Square" [2].
Mining. It doesn't make sense to me that there are so many spots that are larger than Sydney or Melbourne (sprawling cities of 4M people). I wouldn't be surprised to see some lights there, but I highly doubt that the miners are setting up lighting grids that rival the street lights of cities 70km by 70km in size.
(edit: for comparison, Greater Melbourne and Greater London are roughly the same size)
It can't be mining, otherwise we would see similar patterns in South Australia (at least) with similar patterns likely to be visible in every other state as well.
I'd be interested in knowing why this is so as well.
There's similar patterns in north central Siberia (loaded with primary resources) and a couple of other places. There's a weird bloom affect on these spots that's not evident in populated parts of the map. You can even see the bloom effect on the north coast of Alaska, where I'd be extremely surprised that there's light of that level.
My guess is that they didn't quite finish the job off right and got lazy when manipulating these areas.
While I find these images extremely interesting, let me add a contrarian voice: the associations that such night-time photos bring up in me are primarily about waste and habitat destruction.
And to add a contrarian-contrarian voice: Similar day-time photos make the earth look almost entirely uninhabited. Not trying to make a point either way, but I find the contrast fascinating.
"We" don't destroy our immediate habitat, "we" destroy other people's habitats. Wasn't until recently that it became obvious that such a behavior destroyed our own habitat regardless, and even today it's not clear to many people why they should stop. Until then it was just a morality problem, and capitalism has no notion of morality.
How bright should lights be to turn up on this? Why can't we see Aircraft carriers/Big merchant vessels or offshore oil wells or even research stations on the Antartic?
One interesting place is down the south of Argentina, off the east coast. Although there is no land there, there is the (almost spiral) pattern of lights in the ocean. They seem about as bright as Melbourne, and more expansive.
I was told once that these are fishermen, who tend to congregate in one area at night time. I'm not sure if it is for social reasons, or business reasons, or something else.
While perhaps some are offshore oil rigs [1] - many are arrays of lights used to attract bait fish, phytoplankton, and squid [2] in order to increase commercial fishing yields.
It would be great to have this integrated into a mapping software lige google maps, next to the existing day time satellite layer.
For instance, this would be useful to find good spots for watching the stars at night or to find remote camping spots or hiking areas.
I've seen heatmaps of the population density of the USA before, so I shouldn't be surprised. But seeing the city lights at night... I feel like that's a real fact now, not just an abstraction.
In the world map you can clearly see where North Korea is: just look for the really clean line. Pretty depressing.
On the US map, west of New Jersey (or south-west of NYC, if that is easier to find), you can somewhat faintly see that the light outlines the shape of the Appalachian Mountains. Check out the Google maps relief map of Pennsylvania as a comparison: http://goo.gl/7xsN9
Having lived inside London for the past year and a half, the M25 is a decent psychological barrier between London and the rest of the country but seeing it as a pretty distinct glowing line was something else.
Does anyone know what the dark area on the FL/GA border is? I never realized it was unpopulated and Google Maps doesn't give much information about the area as a whole.
its postings like these that inspire me to think that the internet and the web is just a means of a global communication tool to create unity -- thanks.
