Maths of How India’s Coastline Lengthened without Gaining Land

Syllabus: GS1/ Geography

In Context

• The Ministry of Home Affairs, in its 2023–24 report, updated India’s coastline length to 11,098.8 km, a significant increase from the previously recorded 7,516.6 km.
  • This change stems not from any territorial acquisition or natural geological expansion, but from enhanced mapping precision, underscoring the “coastline paradox.”

Coastline Paradox

• Definition: The coastline paradox states that the length of a coastline depends on the scale at which it is measured. The more detailed the measurement (smaller ruler), the longer the coastline appears.
• Euclidean Geometry: Deals with ideal shapes and straight lines/smooth curves, where length is straightforward.
• Fractal Geometry: Coastlines exhibit fractal-like properties, meaning they display self-similar patterns at different scales. This concept was popularized by Benoît Mandelbrot.
• Hypothetical Infinity: Theoretically, measuring a coastline down to the size of a water molecule would result in its length approaching infinity.

New Measurement Methodology and Technology

• Agencies Involved: National Hydrographic Office (NHO) and the Survey of India.
• Finer Scale: Electronic navigation charts at a much finer resolution of 1:250,000.
• Technologies Used: Geographic Information Systems (GIS), Satellite Altimetry, LIDAR-GPS & Drone-based imaging.
• Measurement Reference: Highwater lines prepared by the NHO based on 2011 data on electronic navigation charts. River mouths and creeks were closed off at a fixed inland threshold.
• Inclusion of Islands: Islands exposed at low tide were also included in the review.
• Future Revisions: The coastline length will be revised every 10 years from 2024-2025, ensuring continuous accuracy.

Implications of the Revised Coastline Length

• Disaster Management and Climate Adaptation: India’s east coast is prone to cyclones (e.g., Fani, Yaas) and tsunamis.
  • Accurate coastline data improves early warning systems, evacuation route planning, CRZ (Coastal Regulation Zone) zoning.
  • Supports climate vulnerability assessments and resilient coastal infrastructure development.
• Economic Zoning and Blue Economy Expansion:
  • Influences the computation of India’s Exclusive Economic Zone (EEZ).
  • Extends reach over marine fisheries, deep-sea mining, bioprospecting, and offshore energy.
  • Enhances viability of Sagarmala, coastal industrial corridors, and port-led growth models.
  • Coastal Governance and Urban Planning
• Better data supports:
  • Shoreline management plans
  • Urban zoning laws
  • Port placement and dredging
  • Helps states like Tamil Nadu, Kerala, Gujarat, and Odisha optimize coastal investments.

Challenges and Way Forward

• Dynamic Nature of Coastlines: Coastlines are constantly changing due to tidal fluctuations, sedimentation, erosion, and sea-level rise. Regular revisions are crucial.
• Inter-agency Coordination: Continued collaboration between agencies like the NHO, Survey of India, and other relevant ministries (e.g., Ministry of Earth Sciences, Ministry of Environment, Forest and Climate Change) is vital.
• Technological Upgradation: Continued investment in advanced technologies for mapping and monitoring is necessary.
• Capacity Building: Training and capacity building for personnel involved in coastal management and security.

Source: TH