The Landsat mission has been taking satellite imagery and data of Earth for 40 years. One of the primary benefits of such a record is the ability to study changing landscapes.
To celebrate the launch of the first Landsat satellite on July 23, 1972, the USGS and NASA asked the public to nominate landscapes that have undergone a lot of environmental change for a closer look. The Landsat team chose these six submissions and created customized chronicles of the change in each area.
If you're feeling inspired, you can check out these tutorials on using Landsat data and try putting your own scene together.
Above:
Lee County, Florida
Submitted by: Carole Holmberg
Warm winters, white sand beaches and clear coastal waters were drawing people to Lee County, Florida, and the greater Fort Myers area before the first Landsat satellite launched in 1972. The communities along the lower Caloosahatchee River and a few dotting the nearby coastal islands, such as Sanibel, remained small and quiet until the Second World War, when several air bases around Fort Myers brought thousands of servicemen to the area.
During the 1950s and 1960s retirees and others seeking semi-tropical living flocked to Florida. By 1970, the population of Lee County had grown to about 105,000, with 15.2 percent of the residents being 65 years of age and older, compared to 9.9 percent nationally.
This Nov. 17, 1972, false-color infrared Landsat image (presented in bands 4-2-1) shows that much of the developed land is concentrated along the banks of the Caloosahatchee River, with the city of Cape Coral extending inland, north of the river.
The large bright areas to the northwest of Cape Coral, along with several directly west of the city, indicates that large-scale building was ongoing as land was prepared for street construction and parcelization. Much of Lee County's unique landscape of coastal mangroves, upland pine flatwoods, cypress domes, upland prairies and marshlands, along with existing agricultural land uses, can be seen as red, with darker red for the natural land covers and lighter red for farmland; vegetation strongly reflects near infrared energy, making vegetation in false-color infrared images appear in red hues.
The impervious surfaces of streets, roads, rooftops, and parking lots appear a brighter cream color. Mangrove forests (in red) can be seen on the mainland side of Matlacha Pass (the coastal water west of most of the urbanized area) as well as ringing most of Little Pine Island, Pine Island, and the north side of Sanibel Island.
Lee County's population greatly expanded during the next nearly 40 years. Carole Holmberg who submitted this "American Landscape" contest essay described the changes she has observed in this manner:
"Forty years ago, the area around the [Calusa] Nature Center was agrarian and nearby homes, businesses, and the interstate had not yet been built. Now, our 105-acre property is an island of green in the middle of sprawl."
In 2010, nearly 620,000 people called the county home. The leading employer in Lee County in 2012 is a health care system and three more of the top 22 employers (500 employees or greater) are health or geriatric care facilities. The greater Fort Myers area has also become a leader in southwest Florida education, telecommunications, retailing and general services. Large tracts of the county are urbanized but not incorporated within a distinct municipality.
The area's land covers have undergone substantial change as observed by the Sept. 14, 2011, Landsat image (shown in bands 4-3-2). On the north bank of the river, almost everything east of the mangrove perimeter is developed land. A large tract of natural land covers exists in the northern part of the county on the edge of the imagery. This area is part of the Babcock Ranch Preserve, a working rural landscape supported by a recent and unique public-private partnership.
On the Fort Myers (south) side of the river, new development stretches south inland from the coast, bracketing highways that link Lee County with Naples, another hot spot of urbanization in southwest Florida. Numerous water bodies are visible east of the newer built-up areas, probably associated with the mining of aggregates, the crushed stone and gravel that are used in asphalt, concrete and other construction materials.
Most of the agricultural fields seen in the 1972 imagery have been urbanized. According to the Census of Agriculture, total cropland in Lee County decreased over 5,000 acres between 1974 and 2007, although the conversion of natural land covers to agriculture in the eastern part of the county may have masked greater farmland losses closer to the urbanizing areas.
Images: USGS EROS Data Center
Caption: Roger Auch, Research Geographer, USGS EROS Data Center