In this monthly feature, we span the globe to examine Our Changing Landscape with a time series of medium-resolution PlanetScope satellite imagery. The PlanetScope constellation dates back to 2016 and collects hundreds of millions of square kilometers of four and five-band 3-meter imagery daily! Last month we checked out the destruction left behind by a tornado in the United States, and for the July 2021 edition of Our Changing Landscape we shift our focus to international geopolitics with a look at Fiery Cross Reef in the South China Sea.

Click on the image above to see an animation of 3-meter natural color PlanetScope imagery collected over Fiery Cross on April 6, 16 and 28 and May 1, 2021. We had hoped to see significant changes in these images when it came to shipping traffic in and out of the port, but unfortunately that did not work out. Here are the observations we can offer about this layer stack. First there is a boat patrolling the inner harbor area of Fiery Cross which is in a different position in each image, so if there had been traffic coming in and out of the port, we would have seen it with 3-meter PlanetScope data. Second, there is significant environmental damage done to the reefs surrounding Fiery Cross including a large dredged channel into the main harbor. And finally, even in a remote location such as the middle of the Pacific Ocean, the 3-meter PlanetScope archive is extremely robust and could help monitor shipping traffic to and from remote port locations. (Images Courtesy: © Planet 2021)

The PlanetScope Microsat Constellation

PlanetScope is a constellation of more than 150 microsats referred to individually as Doves. Each Dove is able to collect up to 20,000 square kilometers (sq km) per day of 3-meter (m) 4-band multispectral (i.e. blue, green, red and near-infrared [NIR]) imagery; and newly launched SuperDoves collect 5-band multispectral adding in valuable red-edge spectral data. Across the constellation, PlanetScope is archiving more than 200 million sq km of medium-resolution imagery a day, making it the go to source for daily imagery over most locations. This massive archive dates back to 2016, offering the most complete and continuous record of spatial data on the planet since the start of the constellation’s ongoing launch schedule. Collecting 3-meter multispectral imagery is the equivalent of ‘high-resolution’ multispectral data imaged by a 75-centimer (cm) satellite (as this satellite would feature 75-cm panchromatic and 3-m multispectral), making PlanetScope an extremely competitively priced option at just $1.80 per sq km. With well registered images and nearly daily collections of most locations, PlanetScope is the ideal imagery source for this current-events focused series, Our Changing Landscape.

April and May 2021 Maritime Traffic To/From Fiery Cross Reef

Fiery Cross Reef is a tiny reef on the southern side of the South China Sea first named in 1860 when a British shipping boat wrecked there. In a remote South China Sea location, Fiery Cross is actually nearly equidistant and closest to Vietnam’s coast to the west, and then Palawan Island in the Philippines to the east, at about 300 miles or 482 kilometers. However, and this is where the story gets interesting, the tiny reef is part of a zone called the 9-Dash Line that has its roots in the end of World War II. In 1947, China published a map depicting a wide sweeping region of the South China Sea where it planned to exert military power as a sort of defensive buffer zone.

This exercise of power is essentially a take over of small remote islands and/or reefs plus the creation of artificial islands in the South China Sea whereby China builds military bases and sometimes agricultural zones. According to the Asia Maritime Transparency Initiative, Fiery Cross Reef was converted into a Chinese military base mostly during 2017. The disputed take-over of Fiery Cross includes a sprawling air force base and radar installations that cover about 27 acres or 110,000 square meters. International stories have noted maritime activity around many of the disputed lands, including at Fiery Cross. This fact combined with our recent success at detecting shipping vessel by the Suez Canal with 3-meter PlanetScope imagery, it seemed like an intriguing idea to look at the area around Fiery Cross Reef to see if we could detect any maritime activity in the past few month

If you would like to find out more about using 3-meter PlanetScope imagery for your academic studies, engineering projects or any landscape analysis, let us know at sales@apollomapping.com or (303) 993-3863.