What are raster and vector data models in GIS, and when is each used?

• A. Raster stores data as grids of cells; vector uses points, lines, polygons; Raster is useful for continuous data like elevation; Vector for discrete features like roads and boundaries.
• B. Raster uses points; Vector uses grids.
• C. Raster is for vector data; Vector for raster data.
• D. They are the same.

Answer: (A)

In GIS, the way spatial information is stored shapes how you analyze it: a raster model uses a grid of equally sized cells, with each cell holding a value, while a vector model uses discrete geometries—points, lines, and polygons—to represent features. This makes raster ideal for continuous phenomena where values change gradually across space, such as elevation, temperature, or rainfall, because you can analyze and visualize smooth surfaces across the grid. Vector, on the other hand, excels at representing discrete features with precise boundaries and relationships, like roads as lines, parcels as polygons, and boundaries as polygons, and it supports topology and network analyses. In practice, you’d use raster for continuous surfaces and raster-based analyses, and vector for discrete features and exact boundaries, though you can convert between forms when needed.