Hyperspectral Imaging. Remote Sensing

Hyperspectral imaging is an advanced remote sensing technique that goes beyond multispectral imaging. Instead of capturing data in a few discrete spectral bands, hyperspectral sensors capture data in hundreds of narrow and contiguous bands across the electromagnetic spectrum. This detailed spectral information allows for the identification and characterization of materials and substances with a high degree of precision.

Hyperspectral imaging is particularly useful for tasks such as mineral exploration, environmental monitoring, agriculture assessment, and pollution detection. It can help detect subtle differences in surface materials, vegetation health, and chemical composition that might be missed by traditional multispectral sensors.

Some important satellites with hyperspectral sensors include:

1. Hyperion (onboard EO-1): Hyperion was one of the first hyperspectral sensors in space, launched aboard NASA's Earth Observing-1 (EO-1) satellite. It captures data in 220 spectral bands, providing high-resolution hyperspectral imagery for various applications.

2. EnMAP (Environmental Mapping and Analysis Program): EnMAP is a German satellite designed specifically for hyperspectral imaging. It aims to monitor the Earth's environment and resources with a focus on applications like agriculture, forestry, and land cover mapping.

3. CHRIS (Compact High-Resolution Imaging Spectrometer): CHRIS is a hyperspectral sensor flown on the European Space Agency's (ESA) Proba-1 satellite. It provides detailed hyperspectral data for land and coastal zone applications.

4. PRISMA (PRecursore IperSpettrale della Missione Applicativa): PRISMA is an Italian satellite dedicated to hyperspectral remote sensing. It offers high spatial and spectral resolution data for applications such as agriculture, forestry, and environmental monitoring.

5. HyspIRI (Hyperspectral Infrared Imager): Although not yet launched, the proposed HyspIRI mission from NASA aims to provide global hyperspectral and thermal infrared data for studying Earth's ecosystems, geology, and natural hazards.

Hyperspectral imaging satellites contribute significantly to our understanding of the Earth's surface composition and properties, enabling scientists and researchers to gather detailed information for a wide range of applications.

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Platforms in Remote Sensing

In remote sensing, a platform is the physical structure or vehicle that carries a sensor (camera, scanner, radar, etc.) to observe and collect information about the Earth's surface. Platforms are classified mainly by their altitude and mobility : Ground-Based Platforms Definition : Sensors mounted on the Earth's surface or very close to it. Examples : Tripods, towers, ground vehicles, handheld instruments. Applications : Calibration and validation of satellite data Detailed local studies (e.g., soil properties, vegetation health, air quality) Strength : High spatial detail but limited coverage. Airborne Platforms Definition : Sensors carried by aircraft, balloons, or drones (UAVs). Altitude : A few hundred meters to ~20 km. Examples : Airplanes with multispectral scanners UAVs with high-resolution cameras or LiDAR High-altitude balloons (stratospheric platforms) Applications : Local-to-regional mapping ...

Types of Remote Sensing

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Model GIS object attribute entity

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Resolution of Sensors in Remote Sensing

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Energy Interaction with Atmosphere and Earth Surface

In Remote Sensing , satellites record electromagnetic radiation (EMR) that is reflected or emitted from the Earth. Before reaching the sensor, radiation interacts with: The Atmosphere The Earth's Surface These interactions control how satellite images look and how we interpret them. I. Interaction of EMR with the Atmosphere When solar radiation travels from the Sun to the Earth, four main processes occur: 1. Absorption Definition: Absorption occurs when atmospheric gases absorb radiation at specific wavelengths and convert it into heat. Main absorbing gases: Ozone (O₃) → absorbs Ultraviolet (UV) Carbon dioxide (CO₂) → absorbs Thermal Infrared Water vapour (H₂O) → absorbs Infrared Concept: Atmospheric Windows These are wavelength regions where absorption is very low, allowing radiation to pass through the atmosphere. Remote sensing depends on these windows. For example, satellites like Landsat 8 use visible, near-infrared, and thermal bands located in atmospheric windows. 2. Trans...

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