Vineesh V, Geography

The Model of Geographical Enquiry is a step-by-step method used by geographers to study any spatial problem — like floods, urban growth, crime, climate change, etc. It has five stages : Pattern – What is happening and where? (Observation and Identification) This stage identifies the spatial pattern of a phenomenon. 🔎 What we do: Collect data Map the distribution Identify clusters, trends, or hotspots 📌 Example 1: Floods Suppose we study floods in Kerala. We map flood-affected districts. We notice severe flooding in low-lying river basins. 👉 Pattern: Floods are concentrated near major rivers like Periyar and Pamba. 📌 Example 2: Urban Growth Using satellite images: We observe built-up area increasing around city centers. 👉 Pattern: Urban expansion is concentrated along highways. Process – Why is it happening there? (Explanation and Analysis) Now we explain the reasons behind the pattern. 🔎 What we do: Analyze causes Study physical and human factors Use statistical or GIS analysis...

The environment means everything around us that affects living things, including humans. Biotic components – Living things like plants, animals, and humans. Abiotic components – Non-living things like air, water, soil, climate, and landforms. Built / Cultural Environment – Things created by humans such as cities, roads, dams, and farms. 👉 In simple words: Environment = Nature + Living things + Human-made surroundings. Environmental Thought Environmental thought means ideas about how humans and nature are connected . These ideas changed over time. Major Theories 1. Environmental Determinism Says nature controls humans . Example: People in cold areas wear warm clothes and build strong houses. 2. Possibilism Says nature gives limits, but humans can choose how to live . Example: Desert areas have less water, but humans build canals and irrigation. 3. Neo-determinism (Stop-and-Go Determinism) Says humans can develop using nature but must respect environmental limits. Example: Excess in...

Environmental Geography studies the relationship between humans and nature in a spatial (place-based) way. It combines Physical Geography (natural processes) and Human Geography (human activities). A. Early Stage 🔹 Environmental Determinism Concept: Nature controls human life. Meaning: Climate, landforms, and soil decide how people live. Example: People in deserts (like Sahara Desert) live differently from people in fertile river valleys. 🔹 Possibilism Concept: Humans can modify nature. Meaning: Environment gives options, but humans make choices. Example: In dry areas like Rajasthan, people use irrigation to grow crops. 👉 In this stage, geography was mostly descriptive (explaining what exists). B. Evolution Stage (Mid-20th Century) Environmental problems increased due to: Industrialization Urbanization Deforestation Pollution Geographers started studying: Environmental degradation Resource management Human impact on ecosystems The field became analytical and problem-solving...

dominantly aggradational stacking pattern with subordinate progradational intervals. 

Change detection is the process of finding differences on the Earth's surface over time by comparing satellite images of the same area taken on different dates . After supervised classification , two classified maps (e.g., Year-1 and Year-2) are compared to identify land use / land cover changes .  Goal To detect where , what , and how much change has occurred To monitor urban growth, deforestation, floods, agriculture, etc.  Basic Concept Forest → Forest = No change Forest → Urban = Change detected Key Terminologies Multi-temporal images : Images of the same area at different times Post-classification comparison : Comparing two classified maps Change matrix : Table showing class-to-class change Change / No-change : Whether land cover remains same or different Main Methods Post-classification comparison – Most common and easy Image differencing – Subtract pixel values Image ratioing – Divide pixel values Deep learning methods – Advanced AI-based detection Examples Agricult...

Accuracy assessment is the process of checking how correct your classified satellite image is . 👉 After supervised classification, the satellite image is divided into classes like: Water Forest Agriculture Built-up land Barren land But classification is done using computer algorithms, so some areas may be wrongly classified . 👉 Accuracy assessment helps to answer this question: ✔ "How much of my classified map is correct compared to real ground conditions?"  Goal The main goal is to: Measure reliability of classified maps Identify classification errors Improve classification results Provide scientific validity to research 👉 Without accuracy assessment, a classified map is not considered scientifically reliable . Reference Data (Ground Truth Data) Reference data is real-world information used to check classification accuracy. It can be collected from: ✔ Field survey using GPS ✔ High-resolution satellite images (Google Earth etc.) ✔ Existing maps or survey reports 🧭 Exampl...

A Relational Database Model stores data in the form of tables . Each table contains: Rows → Individual records Columns → Attributes or fields Tables can be connected using common fields called keys . Terminologies 1. Table A collection of related data arranged in rows and columns. Example: ID Name Population 1 Palakkad 130000 2 Thrissur 315000 2. Row (Record) Represents one feature or entry. 👉 Example "Palakkad" is one record. 3. Column (Field / Attribute) Represents one property of data. 👉 Example Population is a field. 4. Primary Key A unique field used to identify each record. 👉 Example ID column. 5. Foreign Key A field used to connect two tables.  Example in GIS (QGIS / ArcGIS) Suppose you have: Table 1: District Boundary Layer District_ID District_Name 1 Palakkad 2 Malappuram Table 2: Rainfall Data District_ID Rainfall 1 2200 mm 2 2800 mm 👉 Both tables share District_ID Using this field, GIS joins rainfall data to district maps. Where Used in GIS Attribute tables of...

In Geographic Information Systems (GIS) , a lot of spatial and attribute data are stored in files. Managing these files properly helps in fast searching, updating, and analyzing geographic data . 1️⃣ Simple List File (Unordered File) ✅ Concept A Simple List File is the most basic way of storing data. Records are stored one after another without any order . 👉 There is no sorting or indexing . ✅ Example in GIS Suppose you are storing details of villages in a district. Village ID Village Name Population 103 Kottayi 5400 101 Chittur 12500 107 Nallepilly 8200 Here, the data is stored randomly. IDs are not arranged in order. ✅ How Searching Works If you want to find Village ID 107 : GIS must check each record one by one This takes more time if data is large. ✅ Advantages ✔ Easy to create ✔ Suitable for small datasets ❌ Disadvantages ✖ Slow searching ✖ Difficult to manage large spatial databases 2️⃣ Ordered Sequential File ✅ Concept In an Ordered Sequential File , records are stored in a so...

Disaster Risk Reduction 

Weighted Overlay is a widely used spatial decision-making technique in Geographic Information Systems (GIS). It functions as an analytical method that balances multiple spatial factors by assigning relative importance to each variable. Essentially, it integrates scientific reasoning with logical evaluation to determine the suitability of locations for specific purposes. In simple terms, Weighted Overlay is a method that combines several spatial raster layers. Each layer represents a different factor influencing the decision-making process. Before integration, the values of each raster layer are standardized to a common evaluation scale, typically ranging from 1 to 5 or 1 to 9. Subsequently, each layer is assigned a weight based on its relative importance. The final suitability value for each cell is calculated by summing the weighted contributions of all layers. The conceptual formula can be expressed as: Final Suitability Value = (Layer 1 × Weight 1) + (Layer 2 × Weight 2) + ... + (La...