The 40 year archive of Landsat data is a valuable resource, supporting many different areas of focus for all users. We have compiled these stories, and will be adding more to this page. We also invite you to send us your story on how Landsat data has helped with your projects...you may send stories to firstname.lastname@example.org. (References to non-U.S. Department of Interior (DOI) products do not constitute an endorsement by the DOI.)Expand All | Collapse All
Added June 18, 2013
Each year a bizarre epidemic emerges upon thousands of miles of coastline, stretching from the Caribbean Islands to the Gulf States. This visitation has been considered an unpredictable act of nature and a detriment to beaches everywhere since as long as it has existed. It seems now however, that the tides of change are sweeping in. The visitor is called sargassum, a macroalgae related to kelp or seaweed. Despite sargassum being considered a nuisance for most of its existence, the Sargassum Early Advisory System (SEAS) of Texas A&M University at Galveston (TAMUG) is making huge leaps to learn more about the macroalgae. Thanks to their work it is now apparent that not only can sargassum be tracked and predicted through the USGS’s Landsat imagery but that providing this information to the public saves the taxpayers’ money and takes away many of the inconveniences of the sargassums’ arrival.
SEAS uses many oceanographic techniques to deliver accurate predictions of the time, location and severity of sargassum landings. The SEAS predictive model is 90% accurate, forecasting sargassums' arrival up to two weeks out. The primary means of tracking the large sargassum mats is through USGS’s Landsat imagery. Weather buoys and beach cameras are also used for accurate monitoring of current weather conditions and confirmation of sargassum landings.
The SEAS team has developed effective yet simple methods for spotting and correctly identifying sargassum through the use of USGS Landsat imagery. Researchers look for irregularities in the water, caused by the sargassum mats, which are referred to as “slicks”. These are areas of irregular disrupted water adjacent to a mat which may be too small to be detected itself; the slicks appear as dark dendritic veins, through the water.
Figure 1. This Landsat image (Path 25 Row 40, acquired May 18, 2012) displays a mat of sargassum approaching the Texas shoreline.
The SEAS team has focused a large part of its energy and resources on getting USGS’s Landsat information out to the public whether that would be a school or beach managers. High schools were specifically targeted as a way to reach out to the public. Students were invited to TAMUG’s computer laboratories and trained in the processes of analyzing Landsat images. In every instance the SEAS team was successful in training the students, so much so that they continued to analyze the images at school and sent in their products to the SEAS team as the year went on. The public is beginning to see that if they understand sargassum and its natural cycle that it can be planned around and no longer disrupt their beach plans.
Beach managers were a target audience for the useful information that can be gleaned from analyzing the USGS Landsat data. It now allows them to know the amount of sargassum to expect as well as when and where to expect it. This means that the sargassum is cleaned up and dealt with more efficiently. This saves the taxpayers money and reduces the inconvenience to the tourists coming to enjoy a pristine beach.
SEAS utilizes Landsat imagery to aid the local beach managers and communities in building a base of citizens who strive to solve problems in the most environmentally and economically savvy ways possible. (Brandon N. Hill, SEAS/TAMUG)
Added August 2, 2012
The presence of birds near an aircraft runway is a constant concern. Although deadly crashes are rare, a bird strike to the windshield can cause visibility issues for pilots, and strikes to jet engines can cause engine failure. Flocks of birds are particularly dangerous, with the threat of multiple strikes at the same time to the same aircraft.
Flocks of formerly endangered Aleutian Cackling Geese enjoy the summertime in the Near Islands at the far western end of Alaska's Aleutian Islands, which is also home to Eareckson Air Station. The air station is located on Shemya Island, the only island in the group where introduced Arctic Foxes have been allowed to remain. The foxes ensure that the geese are not present on Shemya during the nesting and molting seasons of mid-summer. However, flocks of geese arrive in the spring as grasses grow early in the season abundant with nutrients. As they prepare to migrate south in the fall, the geese move to shrubby areas loaded with berries and to vegetation that greened up late in the summer, where they can eat well before their journey. The increasing goose population in recent years has elevated the risk for bird strikes at Eareckson Air Station. The Bird Aircraft Strike Hazard (BASH) prevention program was implemented by the Department of Defense to provide the safest flying conditions possible.
While you cannot see the birds from space, Matthew Macander and Christopher Swingley of ABR, Inc. Environmental Research & Services mapped the presence or absence of snow and spatio-temporal dynamics of the grassy and shrubby habitats in the Near Islands with Landsat satellite images. Based on the resulting maps, an ABR team including Matt, Gerald Frost, Mark Winterstein, and Patricia Miller visited the islands in spring 2008 and fall 2009 and conducted a habitat-use analysis by counting current-season scat.
Back in the office, they mapped where the geese spent time in the spring and fall, and compared the scat counts with the Landsat images. They determined that there was a key 10-day period needed for BASH mitigation in spring. After their arrival, the geese rapidly moved on as snowmelt proceeded on other islands in the Aleutian Chain. The ABR team additionally recommended mitigation strategies that include habitat modification such as vegetation removal or the types of seeds to avoid when re-vegetation is necessary due to disturbance.
The mapping of habitat with Landsat is hardly a unique application of the data; however, the information gained from the mapping of preferred geese habitat in this very remote region, as well as field surveys, enables new and valuable applied information on BASH mitigation. This knowledge can reduce costs of aircraft repair from multiple strikes and could save the lives of military personnel.
Figure 1. Landsat 7 ETM+ image displaying Shemya Island with Eareckson Air Station, acquired October 8, 2003.
Added August 2, 2012
Dr. Stephanie Hulina, President of Geospatial Data Analysis Corporation (GDA Corp) discusses how access to free Landsat imagery from USGS enables her business to provide value-added products to her company's clients. The long-term continuity of the Landsat mission is essential to her company's ability to maintain a competitive edge in today's global economy. Access to readily available Landsat imagery has helped GDA to expand rapidly and serve agricultural, environmental, and resource management clients, some of whom were previously unaware of the tremendous value that Landsat data and its analysis can bring to their decision-making and ultimately their bottom line.
It turns out that GDA is the second largest commercial downloader of Landsat imagery from the USGS worldwide. Not bad for a small business that formed in 2004 from a NASA Small Business Innovation Research (SBIR) project on developing a fully automated procedure for identifying clouds and their shadows in Landsat-class imagery (http://www.gdacorp.com/casa/). From that one project, GDA has branched out to develop a handful of image processing techniques for a range of commercial and government satellites and serves a multitude of clients across the globe. Landsat, however, is the sensor that GDA turns to repeatedly to solve to solve client problems, either at client request or by suggestion from GDA. Dr. Hulina notes, "Landsat imagery is the workhorse sensor at GDA. Its 30 meter resolution, large number of multispectral bands which include NIR and MIR data, its long historical record, along with excellent sensor calibration provides the absolute best bang for the buck compared to all other sensors currently out there for fine level monitoring of local and global land cover and land cover change."
GDA client interests range from detection of data gaps in the imagery, image calibration to surface reflectance, and image mosaicking to full-blown image analysis to answer questions like when, where, and how much of a particular crop is planted in a particular region for any given year. Landsat imagery is exceptionally well suited for agricultural analysis up to the field level. GDA is especially proud of their long-standing working relationship with the Foreign Agricultural Service (FAS) of the USDA. Working with the Office of Global Analysis/International Production Assessment Division within FAS, GDA has used its technology alongside the expertise of the USDA/FAS to provide timely and accurate global crop intelligence while consistently covering all major agricultural regions annually. GDA analysis of Landsat imagery and the final products generated from it factor into the global production forecasts that FAS releases every month. The national importance of FAS activities is evidenced by the inclusion of the "World Agricultural Supply and Demand Estimates and World Agricultural Production (WASDE)" USDA publication in the Office of Management and Budget (OMB) Principal Federal Economic Indicators for the White House.
"The impact of free access to the USGS Landsat imagery on businesses and business opportunities is hard to overestimate," Dr. Hulina notes. "It can be compared to the business opportunities enabled by free access to Google Earth." A significant part of GDA daily business relies on processing and analysis of Landsat imagery and rapid delivery of value-added products to clients. This would not be possible without free, reliable, and high quality Landsat data offered by USGS. "We have developed an end to end processing system around Landsat for our clients. We monitor the USGS EROS archives for new imagery additions and continually collect new images of interest for our clients across the globe. Within seconds of download, these Landsat images are going through our processing system, and we are delivering end-products to clients in hours to several days after ingest depending on the scale of the project.
"We have big plans to continue to push our use of Landsat in new directions and build upon our processing system for existing and new clients. We are very much looking forward to the launch of Landsat 8 and beyond. With this data availability, we see a bright future for GDA and the many clients we serve."
Figure 1. GDA Field-Level Mapping of Soybean Crops in Brazil / Paraguay