I recently came across this video, showing high-res images of cities at night from the ISS (International Space Station). This collection of images is really beautiful and shows the extent of human presence, growth, and activity throughout the world.
They’ve done a nice job of labeling some of the cities that the ISS is able to see in this collection. The notes say, “City lights broadcast our existence into the night of space. Imagine how the Earth will look to astronauts in a century’s time or longer? These images are incredibly difficult to take from a spacecraft traveling along at almost 28,000 kilometers per hour. The images are held at NASA’s Johnson Space Center in a special archive for astronaut photography.”
Take a look at the video and see what patterns emerge. I enjoy seeing how these big cities have built up around the natural landscapes and features – along coastlines, major waterways, and at the confluences of rivers. While looking at these images showing nighttime activity in the cities, we can really see the city’s shape and patterns of growth and planning.
What else can you tell from cities at night? Does the amount of light emitted from cities at night equate with any other demographic or geographic factors?
If we wanted to do some analysis of these images, we can easily open it in ENVI. By applying a Raster Color Slice to the image, we can easily see the road networks and isolate the urban regions and obtain that as a new dataset:
We could use this new dataset to add colorizations and enhance visualization and also to quantify urban changes over time.
This video is labeled Part 1, which presumably means that in the future we’ll see a Part 2 with additional coverage and cities. We may even be able to see some changes between these cities between movies Part 1 and 2. The video closes with an excellent question that we may all ponder: What will Earth look like at night to future astronauts?