Vineesh V, Geography

Topology? Topology can be understood as the "rules of spatial behavior" that govern how geographic features relate to one another in a GIS environment. It defines the logical relationships between points, lines, and polygons, transforming a simple digital drawing into an intelligent and analyzable spatial network . Without topology, GIS data remain visually correct but analytically unreliable. 1️⃣ Adjacency (The "Jigsaw Puzzle" Rule) Concept: Adjacent polygons must fit together seamlessly. Rule: There should be no gaps (slivers) and no overlaps between neighboring polygons. Example: Two adjacent land parcels must share a single, common boundary. A parcel cannot overlap another parcel, nor can empty spaces exist between them—just like pieces of a jigsaw puzzle fitting perfectly. Connectivity (The "Plumbing" Rule) Concept: Line features must connect properly at nodes to form a continuous network. Rule: Lines must connect end-to-end , with no undersh...

Shapefile Components 🔹 .shp — Geometry file What it contains: • The actual geographic shapes (points, lines, polygons) Examples: • City locations (points) • Roads (lines) • Administrative boundaries (polygons) 📌 This is the core file — without it, there is no map. ⸻ 🔹 .shx — Shape index file What it contains: • An index of the geometry file • Allows fast access to shapes 📌 Improves performance when loading and navigating data. ⸻ 🔹 .dbf — Attribute table What it contains: • Attribute data linked to each shape • Stored in dBASE format Examples: • Name, population, area, ID • Road type, length, category 📌 Each row corresponds to one geometry in the .shp file. ⸻ 🔹 .prj — Projection file What it contains: • Coordinate Reference System (CRS) information • Projection, datum, units 📌 Without this file, GIS software does not know where the data is on Earth. ⸻ 🧩 Optional (But Common) Shapefile Files 🔹 ...