Skip to main content

Supervised classification in remote sensing

Supervised classification in remote sensing is a method of using labeled training data to automatically classify pixels or areas in an image. The process typically involves the following steps:


Collecting and preprocessing the image data: This includes acquiring the image data from a remote sensing platform such as a satellite or aircraft, and performing any necessary preprocessing steps such as atmospheric correction or geometric rectification.


Defining training areas and collecting training data: This involves manually identifying and labeling different classes of land cover within the image, such as forests, urban areas, or water bodies. These labeled training areas are used to train the classification algorithm.


Training the classification algorithm: A supervised classification algorithm such as maximum likelihood, decision tree, or support vector machine is used to learn the relationship between the image data and the labeled training data.


Applying the trained classification algorithm to the image: The trained algorithm is then applied to the entire image to classify each pixel or area into one of the defined classes.


Post-classification processing and accuracy assessment: The final classified image is then visually inspected and evaluated for accuracy using metrics such as overall accuracy, kappa coefficient, and confusion matrix.


For illustration, imagine a satellite image of a city. The image is preprocessed to correct for atmospheric effects and geometric distortions. The analyst then defines several training areas within the image, such as a residential area, a commercial area, and a park. They label each of these areas with their corresponding land-use class, such as residential, commercial, and park. The classification algorithm is then trained using these labeled training areas. Once the algorithm is trained, it is applied to the entire image, resulting in a classified image where each pixel is assigned a class label, such as residential, commercial, or park.




Comments

Popular posts from this blog

The global dimensions of disaster

Disasters are not merely natural occurrences but complex interactions between natural hazards and human vulnerabilities. To effectively address disaster risk, we must consider several interconnected dimensions: 1. Vulnerability: Definition: The susceptibility of individuals, communities, or assets to harm from a disaster. Factors: Socioeconomic conditions, geographic location, and environmental factors influence vulnerability. Example: Communities with high poverty rates and limited access to resources are more vulnerable to disaster impacts. 2. Exposure: Definition: The degree to which people, property, and infrastructure are located in hazard-prone areas. Factors: Population density, land use patterns, and infrastructure development influence exposure. Example: Coastal cities with high population density are highly exposed to hurricane and tsunami risks. 3. Capacity: Definition: A community's ability to prepare for, respond to, and recover from disasters. Factors: Strong ...

Overview of Disasters in India

India's Vulnerability to Natural Disasters India's diverse geography and climate make it highly susceptible to a range of natural disasters. These events, including earthquakes, tsunamis, floods, droughts, cyclones, and landslides, can have devastating consequences for millions of people and the economy. Major Natural Disasters Affecting India: Earthquakes: Tectonic Setting: India's position on the Indian Plate, which is colliding with the Eurasian Plate, makes it prone to seismic activity. Impact: Earthquakes can cause widespread destruction, including building collapses, landslides, and tsunamis. The 2001 Gujarat earthquake is a prime example of such devastation. Tsunamis: Oceanic Triggers: Underwater earthquakes and volcanic eruptions can generate tsunamis, as seen in the 2004 Indian Ocean Tsunami. Impact: Coastal areas are particularly vulnerable to tsunamis, which can lead to massive loss of life and property. Floods: Monsoon Influence: India's...

Water Act 1974

The Water (Prevention and Control of Pollution) Act of 1974 is a significant piece of legislation in India aimed at preventing and controlling water pollution. Here are some key facts about the Act: 1. Objective: The primary objective is to prevent and control water pollution and maintain or restore the wholesomeness of water in the country. 2. Establishment of Boards:    - Central Pollution Control Board (CPCB): The Act mandates the establishment of the CPCB to oversee and coordinate activities across the nation and advise the Central Government.    - State Pollution Control Boards (SPCBs): Each state is required to establish its own SPCB to plan comprehensive programs for the prevention and control of pollution. 3. Powers and Functions:    - The Boards have the authority to inspect any sewage or trade effluents, works, and plants for the treatment of sewage and trade effluents.    - They can establish standards for the discharge of pollutants into water bodies and ensure adherence to...

Environment Management DRR

Environmental management plays a crucial role in disaster risk reduction (DRR) by harnessing the power of natural ecosystems to prevent and mitigate the impacts of disasters. By protecting and restoring these ecosystems, we can strengthen community resilience and promote sustainable development. Interconnections Between Environmental Management and DRR: Ecosystem-Based Disaster Risk Reduction (Eco-DRR): Natural Barriers: Ecosystems like forests, wetlands, and coral reefs act as natural barriers, reducing the impact of hazards like floods, landslides, and storm surges. Resilience Building: Healthy ecosystems enhance community resilience by absorbing excess rainfall, preventing erosion, and mitigating the effects of climate change. Environmental Considerations in Disaster Planning: Sustainable Practices: Incorporating environmental considerations into disaster planning helps prevent further environmental degradation, which can exacerbate disaster impacts. Resource Conservati...

Forset management and water conservation

Forest management and water conservation are closely intertwined concepts, as forests play a crucial role in maintaining water resources. Here's an explanation of their connection: 1. Water Regulation: Forests act as natural sponges, absorbing rainwater and releasing it gradually. Trees help regulate water flow, preventing rapid runoff and reducing the risk of floods. 2. Groundwater Recharge: Trees contribute to groundwater recharge by allowing rainwater to percolate into the soil. This replenishes underground aquifers, which are important sources of freshwater. 3. Erosion Control: Forests provide vegetation cover that protects soil from erosion caused by rainfall. This, in turn, helps maintain the quality of water bodies by preventing sedimentation. 4. Streamflow Maintenance: Healthy forests ensure consistent streamflow. Trees release water through transpiration, influencing local and regional precipitation patterns and sustaining rivers and streams. 5. Biodiversity and Water Qual...