CARTOGRAPHY (SOI) — Scale from sheet number A topographic map labeled 47A/16/NW corresponds to which Survey of India scale?

Introduction / Context:
Survey of India (SOI) map numbering follows a hierarchical system. Recognizing scales from sheet codes is a standard cartography skill in Indian competitive exams and fieldwork.

Given Data / Assumptions:

• Sheet code: 47A/16/NW.
• SOI divides maps progressively into smaller areas with larger scales.
• “NW” indicates a quadrant of a larger sheet.

Concept / Approach:
In the SOI series, a 1:50,000 sheet is identified like 47A/16 and covers 15′ × 15′. Each such sheet is subdivided into four quadrants (NW, NE, SW, SE), and these quadrant sheets are at 1:25,000 scale, covering 7.5′ × 7.5′.

Step-by-Step Solution:
Recognize 47A/16 → standard 1:50,000 sheet.Addition of “/NW” → one quarter of that sheet.Quarter-sheets are published at 1:25,000.Hence the scale is 1 : 25,000.

Verification / Alternative check:
SOI indexing manuals show subdivision of 1:50,000 into four 1:25,000 quadrants with compass labels.

Why Other Options Are Wrong:
1:250,000 and 1:100,000 — larger-area, smaller-scale series not indicated by this code.1:50,000 — corresponds to 47A/16 without the quadrant suffix.1:10,000 — finer scale than indicated by the standard quadrant code.

Common Pitfalls:
Assuming any “47A/16” code is always 1:50,000; the quadrant suffix changes the scale to 1:25,000.

Final Answer:
1 : 25,000