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Samatova G.I. student of IV stage, group 401 Department of Geodesy and Geoinformatics Faculty of Land Resources and Cadastre "TIIAME" National Research University
DATA ACQUISTION THROUGH THE LANDSAT SATELLITE
Abstract. The advancement of remote sensing and Earth observation has been greatly aided by NASA's Landsatprogram, which was initiated in 1972. The data collecting method using Landsat satellites is examined in this article, with a focus on the vital information these satellites provide for a variety of fields, including disaster management, agriculture, urban planning, and environmental monitoring. With their multispectral sensors, Landsat satellites provide precise imagery that strikes a balance between global coverage and spatial resolution, creating a reliable long-term record of the Earth's surface. The article addresses issues such data volume, sensor limits, and temporal resolution in addition to discussing the benefits of Landsat data, such as its extensive temporal record and public accessibility. Future developments in sensor capacities, improved data processing methods, and the integration of Landsat data with new technologies should help to overcome existing constraints and increase the program's usefulness. The value of the Landsat program in delivering priceless insights into Earth's changing environment and assisting with well-informed decision-making for upcoming research and applications is highlighted by this article.
Key words: Landsat Program, Earth Observation, Remote Sensing, Data Acquisition, Multispectral Sensors, Environmental Monitoring, Agriculture, Urban Planning, Disaster Management, Temporal Resolution, Spatial Resolution, Sensor Technology, Data Processing, Satellite Imagery, Earth's Surface
Introduction. Launched by NASA in 1972, the Landsat program is one of the most significant and long-lasting Earth monitoring projects. The Earth's surface and its processes have been greatly enhanced by the abundance of data that Landsat satellites have contributed over the last fifty years. The main goal of the initiative is to employ satellite-based imagery to track and record changes in natural resources, the environment, and land use.
High-tech multispectral sensors on board Landsat satellites enable the collection of high-resolution images at many electromagnetic spectrum wavelengths. This capacity makes it possible to see the Earth's surface in great detail, providing insights on a variety of phenomena, from agricultural practices and climatic variability to urbanization and deforestation. For academics, legislators, and environmental managers, being able to track and evaluate these changes over time has proven to be quite beneficial. The reliability of data collection and accessibility are the cornerstones of the Landsat program's legacy.
Because Landsat keeps an extensive record of the Earth's surface, it offers a unique dataset that makes it possible to examine temporal patterns and the effects of both natural and human activity. Because of the program's dedication to open data access, Earth observation has become more accessible and a wider spectrum of users may now utilize this data for a variety of purposes. This article examines the Landsat satellite data gathering process, looking at technology developments, Landsat data applications, and program obstacles. It also covers the potential of Landsat missions in the future and how they can help us better understand how the Earth's ecology is changing. We hope to demonstrate the program's scientific accomplishments and ongoing relevance in tackling global issues through this investigation.
Landsat 1, formerly known as the Earth Resources Technology Satellite, or ERTS, was launched in 1972, marking the start of the Landsat program. Since then, the program has undergone several revisions; as of 2024, Landsat 9 is the most recent satellite to be in service. A variety of imaging sensors that record information at various electromagnetic spectrum wavelengths are carried by each Landsat satellite.
Method of Data Acquisition
1. The Enhanced Thematic Mapper Plus (ETM+) and Thematic Mapper (TM): These sensors are found on Landsat 4 through Landsat 7, and they are capable of capturing multispectral images in many bands, such as thermal infrared, near-infrared, and visible. For the majority of bands, they provide spatial resolutions of 30 meters, and for thermal bands, 120 meters.
2. Thermal Infrared Sensor (TIRS) and Operational Land Imager (OLI): With the exception of the panchromatic band, which has a resolution of 15 meters, the OLI obtains high-resolution multispectral pictures on Landsat 8 and 9 across nine spectral bands at a spatial resolution of thirty meters. Thermal infrared radiation is measured by the TIRS with a resolution of 100 meters.
Gathering and Handling Data: Because of their sun-synchronous orbit, Landsat satellites are able to pass over the same spot on Earth at around the same local solar time. Maintaining a constant timing is essential for tracking changes over time and guarantees that data gathered from many passes can be compared. Several crucial phases are involved in the data collecting process:
• Imaging: Using a variety of spectral bands, the satellite's sensors take pictures of the Earth's surface as it circles the planet. This process spans the planet's whole surface and happens in a methodical manner.
• Data Transmission: Downlink connections are used to send the recorded data to ground stations. Large amounts of data are sent during the transmission, and specialized receiving stations receive them.
• Data Processing: The raw data is preprocessed to account for geometric distortions, atmospheric distortions, and sensor calibration when it is received. In this stage, the data is transformed into an analysis-ready format,
resulting in surface temperature, radiance, and reflectance maps, among other deliverables.
• Distribution and Archiving: Processed data is distributed and preserved via a number of platforms, such as the NASA Earth data website and the United States Geological Survey's (USGS) Earth Explorer. A multitude of uses for the data are ensured by its accessibility.
Landsat data is useful in many sectors.
a. To monitor land deterioration, deforestation, and changes in land use, Landsat imaging is essential. This data is used by researchers to examine how ecosystems are affected by both natural and human-caused events.
b. To monitor crop health, evaluate soil conditions, and improve irrigation techniques, farmers and agricultural scientists utilize data from Landsat. Enhancing agricultural yields and optimizing resource management are made easier with this knowledge.
c. To evaluate infrastructure construction, plan future expansions, and study patterns of urban growth, city planners and developers use Landsat data. The creation of resilient and sustainable urban settings is aided by this data.
d. Landsat imaging is essential for assessing damage, organizing response operations, and planning recovery both during and after natural catastrophes. Efficient acquisition of comprehensive images facilitates efficient catastrophe management.
l.Photo Landsat Evolution We now have a far better knowledge of Earth's dynamic dynamics thanks to the Landsat program. A distinct historical record made possible by the long-term information generated by Landsat satellites is very helpful in identifying patterns and changes over time. Future developments in data processing and sensor technologies are anticipated to improve Landsat data quality and value even more as the program progresses.
Discussion. The significant contribution of the Landsat program to Earth observation highlights its critical role in agriculture, urban planning, disaster management, and environmental monitoring. In light of its significance and
potential, the examination of Landsat's data collecting method highlights both its advantages and prospective improvement areas. Advantages of the Landsat Initiative:
1. Long-Term Data Record: The production of an extensive and ongoing record of the Earth's surface is one of the Landsat program's most important benefits. The reliable coverage and frequent return intervals of Landsat 1 since its 1972 launch have made it possible to analyze temporal changes in great detail. Finding patterns in land use, environmental changes, and climatic fluctuations is made much easier with the help of this long-term dataset.
2. High-Resolution Imaging: By balancing detail and coverage, Landsat's imaging sensors have a spatial resolution of 15 meters for panchromatic bands, 30 meters for multispectral bands, and 100 meters for thermal bands. While still offering useful information at finer geographical scales, this resolution is adequate to track large-scale changes.
3. Global Coverage and Consistency: The sun-synchronous orbits of Landsat satellites guarantee that the same regions are scanned at regular times of the day, allowing for trustworthy data comparison throughout time. For research that need to make temporal comparisons, like tracking seasonal variations or evaluating the effects of natural disasters, this consistency is essential.
4. Accessibility and Public Data: One of the program's strongest points is its dedication to making data accessible to the general public via websites such as USGS Earth Explorer and NASA Earthdata. High-quality data may be used for a variety of purposes by academics, decision-makers, and the general public thanks to this free access, which democratizes knowledge.
Results. Numerous significant findings and insights on the program's effect, capabilities, and uses are revealed by the study of Landsat satellite data gathering. These findings show both the benefits and drawbacks of the data produced by the Landsat satellites, highlighting their efficacy in delivering insightful information in a variety of sectors. The Earth's surface has been effectively documented in a continuous and comprehensive manner by Landsat satellites. This extensive dataset, which covers more than 50 years, provides a distinctive historical viewpoint on alterations in land use, changes in the environment, and fluctuations in temperature. The capacity to consistently obtain high-quality pictures has made it possible for researchers to identify patterns and follow trends that are essential for comprehending the long-term dynamics of the environment. For instance, research has utilized Landsat data to track urban development in the world's largest cities and assess the rate of deforestation in the Amazon jungle.
High-resolution multispectral imagery that strikes a balance between spectral coverage and spatial detail has been continuously provided by the Landsat program. The resolution of Landsat 8 and 9 is 15 meters for the panchromatic band and 30 meters for the majority of bands when they are outfitted with the Thermal Infrared Sensor (TIRS) and Operational Land Imager (OLI). Numerous applications, such as soil moisture assessment, urban planning, and vegetation
health monitoring, have demonstrated the effectiveness of this resolution. Studying surface temperatures and urban heat islands has also benefited greatly from the thermal infrared data collected by Landsat sensors.
Improved Data Accessibility and Public Utilization One of the major accomplishments of the Landsat program is its dedication to data accessibility. The publically available Landsat imagery via platforms such as NASA Earthdata and USGS Earth Explorer has democratized access to high-quality Earth observation data. This accessibility has enabled a variety of uses, from environmental management and scientific research to public education and public awareness campaigns. Local governments and non-profit organizations, for example, have used Landsat data to implement conservation plans and increase public awareness of environmental issues.
Conclusion. Our knowledge of the Earth's surface and processes has been significantly enhanced by the data gathering capabilities of the Landsat program. The program is unmatched in its ability to provide a constant, long-term, and publicly available record of Earth observation, despite various obstacles. Future developments in sensor and processing methods, together with the integration of Landsat data with other technologies, should increase its usefulness and use. Resolving current issues and maximizing the use of Landsat data for upcoming studies and decision-making will need sustained innovation and cooperation.
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