Question

Elucidate any two disadvantages of vector data model in GIS.

Hint:

Vectors are like drawing with a pen—great for sharp outlines, but terrible if you need to smoothly blend colors or map a rolling mountain.

Answer 1

Step 1: Concept
The vector data model uses points, lines, and polygons (defined by X,Y coordinates) to represent distinct spatial features on a map.

Step 2: Meaning
While excellent for precise boundaries and topological relationships, the vector format has inherent computational and representational drawbacks.

Step 3: Analysis

• Complex Data Structure: Storing exact mathematical coordinates, nodes, arcs, and the complex topological relationships between them makes the underlying database architecture highly complex and difficult to manage.
• Poor Continuous Data Representation: Vector models are highly inefficient at representing continuously varying surfaces (like elevation, temperature gradients, or rainfall) because they force continuous data into artificial boundary polygons, unlike a smooth raster grid.
• Intensive Spatial Analysis: Performing complex mathematical overlays (like intersecting multiple irregular polygon layers) requires intensive computing power and complex algorithms.

Step 4: Conclusion
The primary disadvantages lie in its database complexity and its inability to easily model continuous geographic surfaces. Final Answer: 1. The underlying database structure is complex to manage and store. 2. It is highly inefficient for representing continuous spatial surfaces like elevation or temperature.