Raster Data Analysis. GIS

Raster data analysis is a fundamental aspect of GIS that involves working with data represented in a grid-based format known as raster data. Raster data consists of a series of cells or pixels, where each cell represents a value or attribute associated with a specific location on the Earth's surface.

In GIS, raster data analysis refers to the process of manipulating, extracting information, and deriving new insights from raster datasets. This type of analysis enables us to understand spatial patterns, perform calculations, and make informed decisions based on the values within the raster cells.

There are several tools and techniques available for raster data analysis in GIS software. Here are some commonly used ones:

1. Raster Calculator: This tool allows you to perform mathematical operations on raster datasets, such as addition, subtraction, multiplication, and division. It is useful for creating new raster layers by combining or transforming existing ones.

2. Zonal Statistics: Zonal statistics calculates statistics, such as mean, maximum, minimum, or standard deviation, for a specific zone or region defined in a raster dataset. It helps in analyzing and summarizing values within predefined areas of interest.

3. Slope and Aspect Analysis: These tools calculate the slope and aspect of the terrain from elevation raster data. Slope analysis measures the steepness of the land, while aspect analysis determines the orientation or direction of the slope.

4. Reclassification: Reclassification allows you to assign new values or categories to raster cells based on specified criteria. It is helpful in reclassifying continuous data into discrete classes or grouping data for thematic mapping.

5. Density Analysis: Density analysis helps to analyze the concentration or distribution of certain phenomena in a raster dataset. It calculates the density of occurrences within a given area, such as population density or density of crime incidents.

6. Cost Distance Analysis: This tool calculates the least-cost path or distance between locations, considering the cost or resistance values assigned to raster cells. It is commonly used for modeling movement or finding the optimal route based on factors like terrain, land cover, or infrastructure.

7. Suitability Analysis: Suitability analysis assesses the suitability of areas for specific activities or criteria. It involves overlaying multiple raster datasets, assigning weights to each layer, and generating a suitability map to identify areas that meet certain criteria.

These are just a few examples of the numerous raster analysis tools available in GIS software. Each tool serves specific purposes and can be combined to perform complex analyses and generate valuable insights from raster data.

Comments

Types of Remote Sensing

Remote Sensing means collecting information about the Earth's surface without touching it , usually using satellites, aircraft, or drones . There are different types of remote sensing based on the energy source and the wavelength region used. 🛰️ 1. Active Remote Sensing 📘 Concept: In active remote sensing , the sensor sends out its own energy (like a signal or pulse) to the Earth's surface. The sensor then records the reflected or backscattered energy that comes back from the surface. ⚙️ Key Terminology: Transmitter: sends energy (like a radar pulse or laser beam). Receiver: detects the energy that bounces back. Backscatter: energy that is reflected back to the sensor. 📊 Examples of Active Sensors: RADAR (Radio Detection and Ranging): Uses microwave signals to detect surface roughness, soil moisture, or ocean waves. LiDAR (Light Detection and Ranging): Uses laser light (near-infrared) to measure elevation, vegetation...

geostationary and sun-synchronous

Orbital characteristics of Remote sensing satellite geostationary and sun-synchronous Orbits in Remote Sensing Orbit = the path a satellite follows around the Earth. The orbit determines what part of Earth the satellite can see , how often it revisits , and what applications it is good for . Remote sensing satellites mainly use two standard orbits : Geostationary Orbit (GEO) Sun-Synchronous Orbit (SSO) Geostationary Satellites (GEO) Characteristics Altitude : ~35,786 km above the equator. Period : 24 hours → same as Earth's rotation. Orbit type : Circular, directly above the equator . Appears "stationary" over one fixed point on Earth. Concepts & Terminologies Geosynchronous = orbit period matches Earth's rotation (24h). Geostationary = special type of geosynchronous orbit directly above equator → looks fixed. Continuous coverage : Can monitor the same area all the time. Applications Weather...

India remote sensing

1. Foundational Phase (Early 1970s – Early 1980s) Objective: To explore the potential of space-based observation for national development. 1972: The Space Applications Programme (SAP) was initiated by the Indian Space Research Organisation (ISRO), focusing on applying space technology for societal benefits. 1975: The Department of Space (DoS) was established, providing an institutional base for space applications, including remote sensing. 1977: India began aerial and balloon-borne experiments to study Earth resources and assess how remote sensing data could aid in agriculture, forestry, and hydrology. 1978 (June 7): Bhaskara-I launched by the Soviet Union — India's first experimental Earth Observation satellite . Payloads: TV cameras (for land and ocean surface observation) and a Microwave Radiometer. Significance: Proved that satellite-based Earth observation was feasible for India's needs. 1981 (November 20): Bhaskara-II launche...

Natural Disasters

A natural disaster is a catastrophic event caused by natural processes of the Earth that results in significant loss of life, property, and environmental resources. It occurs when a hazard (potentially damaging physical event) interacts with a vulnerable population and leads to disruption of normal life . Key terms: Hazard → A potential natural event (e.g., cyclone, earthquake). Disaster → When the hazard causes widespread damage due to vulnerability. Risk → Probability of harmful consequences from interaction of hazard and vulnerability. Vulnerability → Degree to which a community or system is exposed and unable to cope with the hazard. Resilience → Ability of a system or society to recover from the disaster impact. 👉 Example: An earthquake in an uninhabited desert is a hazard , but not a disaster unless people or infrastructure are affected. Types Natural disasters can be classified into geophysical, hydrological, meteorological, clim...

Linear Arrays Along-Track Scanners or Pushbroom Scanners

Multispectral Imaging Using Linear Arrays (Along-Track Scanners or Pushbroom Scanners) Multispectral Imaging: As previously defined, this involves capturing images using multiple sensors that are sensitive to different wavelengths of electromagnetic radiation. Linear Array of Detectors (A): This refers to a row of discrete detectors arranged in a straight line. Each detector is responsible for measuring the radiation within a specific wavelength band. Focal Plane (B): This is the plane where the image is formed by the lens system. It is the location where the detectors are placed to capture the focused image. Formed by Lens Systems (C): The lens system is responsible for collecting and focusing the incoming radiation onto the focal plane. It acts like a camera lens, creating a sharp image of the scene. Ground Resolution Cell (D): As previously defined, this is the smallest area on the ground that can be resolved by a remote sensing sensor. In the case of linear array scanne...

Vineesh V, Geography

Search This Blog