CAPF AC 2025 Q80: Geography – Cartography & Map Skills
Which of the following statements with reference to raster data format is/are correct?
1. It has a simple data structure which is compatible with remote sensing imagery.
2. The relationship between cell size and number of cells is expressed as the resolution of the raster.
Select the answer using the code given below.
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (c) Both 1 and 2
Explanation
Raster data format in GIS
How to think: a raster stores the world as a grid of cells (pixels), each with one value.
Satellite images are also grids of pixels, so the two fit together.
| Statement | Fact | Verdict |
|---|---|---|
| 1. Simple data structure, compatible with remote sensing imagery | A grid is the simplest structure and matches satellite images | Correct |
| 2. Cell size and number of cells give the resolution | Smaller cells and more of them give a finer resolution | Correct |
Answer: (c) Both 1 and 2.
Why each option is right or wrong
- (a) Incorrect. Statement 2 is also true: resolution depends on cell size.
- (b) Incorrect. Statement 1 is also true: raster data match satellite imagery.
- (c) CORRECT. Both statements describe the raster format.
- (d) Incorrect. Both statements are true.
Key point
Raster: grid of cells, simple structure, suits remote sensing, resolution = cell size. Vector: points, lines, polygons; precise boundaries, smaller files for maps.
Remember
Raster = grid of cells; smaller cells give finer resolution.
Common mistakes
- Mixing raster with vector data, which uses points, lines and polygons.
- Thinking resolution is the number of colours, not the cell size.
- Doubting statement 1 because grids look simple.
Exam tip
Educated guess: both statements are neutral facts of the format. When both read like definitions, 'both' is the likely answer.
Sources
- NCERT Class XII Practical Work in Geography, Part II, Chapter 4 (Spatial Information Technology: raster and vector data)
- Peter A. Burrough and Rachael A. McDonnell, Principles of Geographical Information Systems (Oxford University Press), chapter on data structures