Vineesh V, Geography

Location – Where the object is found on the map or photo. Knowing the place can give clues about what it is. Size – How big or small it appears, which helps identify objects (e.g., a football field vs. a garden). Shape – The outline or form of the object, such as round, rectangular, or irregular. Shadow – The dark area an object casts; it helps guess height, shape, and type of object. Tone/Color – Lightness, darkness, or color differences that help tell objects apart (e.g., blue water, green vegetation). Texture – How smooth or rough the surface looks in the image (e.g., forest appears rough, grassland appears smooth). Pattern – The arrangement or repetition of objects, like rows of trees or grid-like city blocks. Height/Depth – How tall or deep an object or landform is, often estimated from shadows or stereo images. Site/Situation/Association – The surroundings and relationships between objects (e.g., a swimming pool next to a house, or a f...

Time Period Event / Process Geological Evidence Key Terms & Concepts Late Precambrian – Palaeozoic (>541 Ma – ~250 Ma) India part of Gondwana , north bordered by Cimmerian Superterranes, separated from Eurasia by Paleo-Tethys Ocean . Pan-African granitic intrusions (~500 Ma), unconformity between Ordovician conglomerates & Cambrian sediments. Gondwana, Paleo-Tethys Ocean, Pan-African orogeny, unconformity, granitic intrusions, Cimmerian Superterranes. Early Carboniferous – Early Permian (~359 – 272 Ma) Rifting between India & Cimmerian Superterranes → Neotethys Ocean formation. Rift-related sediments, passive margin sequences. Rifting, Neotethys Ocean, passive continental margin. Norian (210 Ma) – Callovian (160–155 Ma) Gondwana split into East & West; India part of East Gondwana with Australia & Antarctica. Rift basins, oceanic crust formation. Continental breakup, East Gondwana, West Gondwana, oceanic crust. Early Cretaceous (130–125 Ma) India broke fr...

Time Period Event / Process Geological Evidence Key Terms & Concepts Late Precambrian – Palaeozoic (>541 Ma – ~250 Ma) India part of Gondwana , north bordered by Cimmerian Superterranes, separated from Eurasia by Paleo-Tethys Ocean . Pan-African granitic intrusions (~500 Ma), unconformity between Ordovician conglomerates & Cambrian sediments. Gondwana, Paleo-Tethys Ocean, Pan-African orogeny, unconformity, granitic intrusions, Cimmerian Superterranes. Early Carboniferous – Early Permian (~359 – 272 Ma) Rifting between India & Cimmerian Superterranes → Neotethys Ocean formation. Rift-related sediments, passive margin sequences. Rifting, Neotethys Ocean, passive continental margin. Norian (210 Ma) – Callovian (160–155 Ma) Gondwana split into East & West; India part of East Gondwana with Australia & Antarctica. Rift basins, oceanic crust formation. Continental breakup, East Gondwana, West Gondwana, oceanic crust. Early Cretaceous (130–125 Ma) India broke fr...

GIS, a network data model is used to represent and study things that are connected like a web — for example, roads, rivers, railway tracks, water pipes, or electric lines . It focuses on how things are connected and helps us solve problems like finding the best route, the nearest hospital, or where water will flow. Nodes → Points where things meet or end (e.g., road intersections, railway stations, pumping stations). Edges → Lines connecting the nodes (e.g., roads, pipelines, cables). Topology → The "rules" of connection — which node is linked to which edge. Attributes → Extra details about each part (e.g., road speed limit, pipe size, traffic volume). How It Works 🔍 Make the Network Model Start with a map of lines (roads, pipes, rivers) and mark how they connect. Run Analyses Routing → Find the shortest or fastest path. Closest Facility → Find the nearest hospital, petrol station, etc. Service Area → Find how far y...

Shortest path analysis is about finding the best route between two places on a map. "Best" can mean shortest distance , least travel time , or lowest cost . It's used in transportation, logistics, urban planning , and many other fields. Key Ideas Network Dataset → A map of connected lines like roads, footpaths, railways, etc. Origin & Destination → Where you start and where you want to go. Impedance → The "cost" of traveling — could be distance, time, money, fuel, etc. Constraints → Rules or limits, like speed limits, traffic jams, toll roads, or road closures. How It Works Define the Network → GIS creates a model of roads or paths. Calculate Cost → For each road segment, GIS figures out the cost (time, distance, etc.). Run Algorithm → Uses formulas like Dijkstra's Algorithm or A* to find the lowest total cost from start to end. Show Results → The route is displayed on the map with info like total ti...

1. Seismicity and Earthquakes in the Indian Subcontinent Key Concept: Seismicity Definition : The occurrence, frequency, and magnitude of earthquakes in a region. In India, seismicity is high due to active tectonic processes . Plate Tectonics 🌏 Indian Plate : Moves northward at about 5 cm/year. Collision with Eurasian Plate : Causes intense crustal deformation , mountain building (Himalayas), and earthquakes. This is an example of a continental-continental collision zone . Seismic Zones of India Classified into Zone II, III, IV, V (Bureau of Indian Standards, BIS). Zone V = highest hazard (e.g., Himalayas, Northeast India). Zone II = lowest hazard (e.g., parts of peninsular India). Earthquake Hazards ⚠️ Himalayas: prone to large shallow-focus earthquakes due to active thrust faulting. Northeast India: complex subduction and strike-slip faults . Examples: 1897 Shillong Earthquake (Magnitude ~8.1) 1950 Assam–Tib...

India in the Plate Tectonic Framework Geological Journey ~150 million years ago – Part of Gondwanaland with Africa, Antarctica, Australia, and South America. ~120 million years ago – Broke away and drifted north across the Tethys Ocean at exceptional speed (~15–20 cm/year). ~50 million years ago – Collided with the Eurasian Plate, closing the Tethys Ocean. Present – Still converging with Eurasia (~5 cm/year), causing active mountain building and earthquakes. Tectonic Plate of India Indian Plate – Once part of Gondwanaland; now includes the Indian subcontinent and surrounding oceanic crust. Collision with Eurasia – Caused the Himalayan Orogeny and uplift of the Tibetan Plateau. Ongoing Movement – Himalayas rise ~5 mm/year; frequent seismic events occur. Current Tectonic Setting North – Convergent boundary with Eurasian Plate → Himalayan uplift, seismicity (e.g., Nepal 2015 earthquake). West – Interaction with Arabian Plate along Ow...

1. Global Plate Tectonics  The theory of Plate Tectonics explains how the Earth's lithosphere (the rigid outer shell) is broken into large pieces called plates . Plates : These plates float over the softer, semi-molten layer beneath, called the asthenosphere . Movement : Driven by heat from Earth's interior (mantle convection, ridge push, slab pull), plates move a few centimetres per year — about the speed your fingernails grow. Boundaries : Where plates meet, we get different interactions: Divergent boundaries – plates move apart (mid-ocean ridges, new crust formation). Convergent boundaries – plates collide (mountains, subduction zones). Transform boundaries – plates slide past each other (earthquakes). Why it matters: This movement shapes continents, mountains, volcanoes, ocean basins, and earthquakes. 2. India's Place in Global Plate Tectonics India's geologic story is one of the most dramatic and fast-moving continental j...

1. Surface Analysis 🗺️ This is when we try to understand and visualize how a value changes across a surface (like land). The values might be temperature, rainfall, elevation, pollution levels, etc. We often start with only some points where we know the value, but we want to guess the values everywhere in between. 2. Interpolation 📍➡️📍 Interpolation is a way of estimating unknown values between known points. Imagine you know the temperature at a few weather stations, but you want to know the temperature everywhere in between. GIS uses math to "fill in the blanks" between the points. 3. IDW (Inverse Distance Weighted) 🎯 One popular interpolation method. The idea: Points that are closer to you have more influence than points farther away. Example: If you're standing between two rain gauges, the closer one's reading will affect your estimated rainfall more than the farther one. "Inverse Distance" means: The ...