Question

Which of the following is a representation of vector map?
(a) Point, (b) Pixel, (c) Polygon

• (a) only
• (b) only
• (a) and (b) only
• (a) and (c) only

Hint:

To remember GIS data models:
- Vector is "discrete" and uses Points, Lines, and Polygons.
- Raster is "continuous" and uses a grid of Pixels.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Geographic Information Systems (GIS) represent spatial data on the Earth's surface using two primary data models: vector and raster.
The vector data model represents real-world features using explicit coordinates (X, Y) to define points, lines, and polygons.
The raster data model represents spatial features as a grid of cell values, where each grid cell is known as a pixel.

Step 3: Detailed Explanation:
Let us analyze each of the given components:
(a) Point:
A point is represented by a single coordinate pair (X,Y) and is used to depict zero-dimensional spatial features such as a well, a soil sampling site, or a city on a small-scale map.
This is a fundamental vector representation.
(b) Pixel:
A pixel (picture element) is the smallest unit of a raster image.
It represents a continuous grid cell containing a specific value (such as elevation or reflectance).
This is a raster representation, not vector.
(c) Polygon:
A polygon is a closed, multi-sided vector feature defined by a series of connected line segments (arcs) where the starting and ending points are the same.
It represents two-dimensional areas such as soil map units, land-use zones, or lakes.
This is a fundamental vector representation.

Step 4: Final Answer:
Point (a) and Polygon (c) are the representations of a vector map.
Therefore, the correct option is (a) and (c) only.