The border of the United States (top) and Mexico (bottom). Image captured December 18, 2015. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

Border Post: Seeing Boundaries from Space

A lot of the time, we hear that the lines drawn on a map aren’t visible in the real world. And most of the time, that’s true. From space, it’s often hard to distinguish borders between countries and territories. Natural borders, like rivers or seas, make it easier to distinguish one country from another. And other times, differences in cultures, economies, and political viewpoints can throw territorial borders into sharper relief. Take a look at some of the world’s more visually interesting borderlands from space.

About 71% of the Earth’s surface is covered in water, so naturally, many borders we see are water borders. The border below is more significant now after the recent Brexit vote — take a look at the English Channel!

The UK (top left) and France (bottom right) on either side of the English Channel. Image captured May 13, 2016. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

This body of water separates the United Kingdom from France (and will soon be the boundary between the UK and the rest of the European Union). Travelers may pass between the two countries by ferry or by car via the famous Channel Tunnel.

Many borders are drawn by rivers — a natural boundary between nations. This stunning, twisting river, the Cubango, separates Angola (top) from Namibia (bottom).

Angola (north) and Namibia (south) are separated by the Cubango River. Image captured March 23, 2016. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

The Namibian side has a variety of agricultural products — maize, wheat, and vegetables are grown as a part of the Ndonga Linena Agricultural Project, whereas the Angolan side of the border is starkly bare.

And of course, when you have rivers, sometimes you get stunning waterfalls as well! Do you recognize these famous falls at international borders?

Niagara Falls (left) and Victoria Falls (right). Images captured October 26, 2015 and May 11, 2016 respectively. Images ©2016 Planet Labs, Inc. cc-by-sa 4.0.

Niagara Falls (left image) is made up of three waterfalls on the Niagara River: Horseshoe Falls, American Falls, and Bridal Veil Falls and lies on top of the border between Canada (left) and the United States (right). Similarly, Victoria Falls (right image) lies on the Zambezi River, which forms the border between Zambia (right) and Zimbabwe (left).

In some instances, three borders come together at a single spot called a tripoint. One tripoint, Tres Fronteras, lies deep in the Amazon rainforest and is where Brazil, Columbia, and Peru meet. The similarly named, Triple Frontier, joins Argentina, Brazil, and Paraguay.

Tres Fronteras (left) and the Triple Frontier (right). Images captured September 12, 2015 and April 3, 2016 respectively. Images ©2016 Planet Labs, Inc. cc-by-sa 4.0.

In the first image, Peru lies to the west of the river, Brazil to the east, and a small sliver of Colombia extends down from the top center. In the second image, the left part of the frame is Paraguay, the top right is Brazil, and the bottom right below the river is Argentina.

While there are no international boundaries between four nations in a single spot, there are plenty of instances where four states or territories come together at a single location or quadripoint. The most famous (at least to us Americans) is the Four Corners, where Arizona, Colorado, New Mexico, and Utah meet.

As viewed clockwise from the top left: Utah, Colorado, New Mexico, and Arizona. Image captured June 25, 2016. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

Look closely and you’ll see the Four Corners Monument in red. In addition to marking the boundary between four US states, the monument also marks the boundary between Native American governments: the Navajo Nation and the Ute Mountain Ute Tribe. The Navajo Nation maintains the tourist site under the jurisdiction of their Department of Parks and Recreation.

At borders, different laws, politics, and cultures come together. These disparities can manifest in many ways we can see from space. Countries can regulate many aspects of our daily lives, including one of the most mundane parts — our daily commutes. Different nations have different laws about which side of the road we drive on. We can see several instances where these laws change over borders, and it is interesting to look at the inventive infrastructure that has been developed to handle the lane switch.

(Left) The border between mainland China and Hong Kong. Image captured May 12, 2016. (Center) The border between China and Macau. Image captured March 3, 2016. (Right) The border between Laos and Thailand. Image captured May 1, 2016. Images ©2016 Planet Labs, Inc. cc-by-sa 4.0.

In the first image, we see the Lok Ma Chau Bridge which joins Shenzhen and the rest of mainland China with Hong Kong. In Shenzhen (upper left) four separate streets are joined together in a giant merging spiral to switch drivers from the right side of the road to the left side as they enter Hong Kong (lower right).

The center image shows the Lotus Bridge which joins Macau (right) and mainland China (left). Drivers in all six lanes on the Chinese side of the bridge experience a 360˚ turn which swaps the handedness of the road.

The image on the right shows the border between Laos (t0p) and Thailand (bottom). An ‘X’ shaped crossover in Laos reverses the side of the road drivers follow as the cross over the Mekong River via the Thai-Lao Friendship Bridge.

Political disputes and negotiations over land can lead to all sorts of interesting border structures. Most borders do not form straight lines, and sometimes, part of one nation ends up entirely surrounded by another in features called enclaves.

Uzbekistan (top) and Kyrgyzstan (down). Image captured July 22, 2015. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

This image shows the border of Kyrgyzstan and Uzbekistan (take a guess where!), but the border is more complicated than it appears on first glance. The Kyrgyz border curves up into the agricultural area (you can see some subtle differences if you look closely — note the denser green fields and barren patches) and there is a small Kyrgyz enclave on the left side of the image.

Different agricultural laws and practices are also visible from space, like this image seen here of the border between Haiti and the Dominican Republic.

The border between Haiti (left) and the Dominican Republic (right). Image captured March 3, 2016. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

The Dominican Republic (right) and Haiti (left) both call the Caribbean island of Hispaniola home. The vast wealth disparity has lead to drastically different farming practices and infrastructure that you can clearly see here in the vegetation and number of roads.

A similar difference in vegetation and infrastructure can be found here and the border of the United States and Mexico.

The border of the United States (top) and Mexico (bottom). Image captured December 18, 2015. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

Calexico, California (top) and Mexicali, Mexico (bottom) straddle the US/Mexico border. You can walk across the border between countries, and many people commute back and forth across the boundary daily for work.

The striking visual effect of a border is also readily apparent in this image of the border of Pakistan and India.

The border between Pakistan (left) and India (right). Image captured April 23, 2016. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

Pakistan (left) and India (right) share a hotly disputed border that runs for miles and miles, as seen here running roughly vertically through the image. Across the image, however, is the Grand Trunk Road with a visible crossing point at the border town of Wagah. At this site, both the Indian Border Security Force and the Pakistan Rangers join together at the border gate to perform the daily Wagah border ceremony.

Border guards are not quite so cordial at the boundary between North and South Korea shown here.

The border of the North Korea (top) and South Korea (bottom). Image captured October 2, 2015. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

In this image, you can clearly see the Korean Demilitarized Zone that separates North Korea (top) and South Korea (bottom). The vegetation grows lush and green in the uninhabited region in the middle that is approximately 2.5 miles wide.

The border between Gaza and Israel is similarly controversial.

The border between Gaza (left) and Israel (right). Image captured April 24, 2016. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.

You can see the striking differences in land use and infrastructure on either side of the border between the Gaza Strip (left) and Israel (right).

But not all borders are quite so stark.

The border between Ukraine (left) and Russia (right). Image captured February 17, 2016. Image ©2016 Planet Labs, Inc. cc-by-sa 4.0.