Major Terms and Regions Explained 1. Indian Shield The Indian Shield refers to the ancient, stable core of the Indian Plate made of hard crystalline rocks. It comprises Archean to Proterozoic rocks that have remained tectonically stable over billions of years. Important Geological Features and Regions ▪️ Ch – Chhattisgarh Basin A sedimentary basin part of the Bastar Craton . Contains rocks of Proterozoic age , mainly sedimentary. Important for understanding the evolution of central India. ▪️ CIS – Central Indian Shear Zone A major tectonic shear zone , separating the Bundelkhand and Bastar cratons . It records intense deformation and metamorphism . Acts as a suture zone , marking ancient tectonic collisions. ▪️ GR – Godavari Rift A rift valley formed due to stretching and thinning of the Earth's crust. Associated with sedimentary basins and hydrocarbon resources . ▪️ M – Madras Block An Archean crustal block in...
What is Overlay Analysis ? Overlay means placing one layer on top of another in GIS to see how they are related. Imagine putting a transparent sheet of roads on top of a map of forests — that's overlay! 1. Point in Line Points are single locations (like bus stops). Lines are long features (like roads or rivers). "Point in Line" means checking which points lie on or near a line . ✅ Example: You have a map of bus stops (points) and roads (lines). You check which bus stops are on which roads . 2. Point in Polygon Polygon is an area (like a city, park, or forest). Point in Polygon means checking which points are inside an area . ✅ Example: You have schools (points) and a map of city boundaries (polygons). You want to see which schools are inside which city . 3. Line in Polygon Now you're checking which lines pass through or are inside areas . ✅ Example: You have rivers (lines) and forests (polygons). You w...