Remote Sensing in India

Remote Sensing in India refers to the science and technology of acquiring information about the Earth’s surface and atmosphere from space-borne or airborne platforms without direct physical contact. It plays a crucial role in natural resource management, environmental monitoring, disaster management, agriculture, and urban planning. India is recognised as one of the global leaders in operational remote sensing applications, largely due to its indigenous satellite programmes, coordinated under the Indian Space Research Organisation (ISRO).

Historical Background and Development

The development of remote sensing in India dates back to the late 1960s when the country began exploring the potential of space technology for national development. The National Remote Sensing Agency (NRSA), established in 1974 under the Department of Space, was instrumental in coordinating remote sensing activities.
India’s first significant exposure to satellite remote sensing came through collaborations with the United States using NASA’s Landsat satellites during the 1970s. These experimental studies, including the Experimental Satellite Communication Earth Station (ESCES) and SITE (Satellite Instructional Television Experiment), demonstrated the value of space-based observations for resource assessment and communication.
The turning point came with the development of indigenous satellites under the Indian Remote Sensing (IRS) programme, which made India one of the few nations in the world with a fully operational remote sensing satellite system. The launch of IRS-1A in 1988 marked the beginning of this successful indigenous capability.

The Indian Remote Sensing Satellite Programme

The Indian Remote Sensing (IRS) series represents one of the world’s largest constellations of Earth observation satellites, designed to meet both civilian and strategic needs. These satellites are equipped with advanced sensors operating in optical, infrared, microwave, and radar bands to collect data on land, ocean, and atmosphere.
Key satellites under the IRS programme include:

• IRS-1A (1988): India’s first operational remote sensing satellite, providing multispectral imagery for resource mapping and land-use planning.
• IRS-1B (1991): Enhanced imaging capabilities for agricultural and forestry applications.
• IRS-1C and 1D (1995–1997): Introduced high-resolution sensors, greatly improving imaging accuracy and coverage.
• Resourcesat Series (2003 onwards): Designed for agricultural and rural development; Resourcesat-2 and 2A provided multispectral, high-resolution imagery for crop monitoring and soil analysis.
• Cartosat Series (2005 onwards): High-resolution mapping satellites used for cartographic and urban planning purposes. Cartosat-3, launched in 2019, provides sub-metre resolution imagery.
• Oceansat Series (1999 onwards): Focused on ocean colour monitoring, sea surface temperature, and wind vector data for fisheries and coastal studies.
• RISAT Series (2009 onwards): Radar Imaging Satellites using synthetic aperture radar (SAR) technology, enabling all-weather, day-and-night observation.
• GISAT and EOS Series: The latest Earth Observation Satellites offering high temporal resolution for near-real-time environmental and disaster monitoring.

These satellites have collectively provided continuous Earth observation data for over three decades, significantly contributing to various national and regional programmes.

Institutional Framework

Remote sensing activities in India are coordinated by ISRO under the Department of Space (DoS). The National Remote Sensing Centre (NRSC), located in Hyderabad, functions as the primary hub for data reception, processing, and dissemination. It provides satellite imagery and geospatial data to government agencies, research institutions, and private users.
In addition, the Indian Institute of Remote Sensing (IIRS) in Dehradun serves as the country’s premier training and research institution in remote sensing and geographic information systems (GIS). Numerous universities and technical institutes also participate in capacity-building through education and applied research programmes.

Applications of Remote Sensing in India

Remote sensing has become an indispensable tool in a wide range of sectors across India.
1. Agriculture:

• Crop acreage and yield estimation under the FASAL (Forecasting Agricultural output using Space, Agro-meteorology and Land-based observations) programme.
• Monitoring of irrigation projects, soil moisture, and pest/disease detection.
• Drought and flood assessment for agricultural planning.

2. Forestry and Ecology:

• Forest type mapping, biomass estimation, and monitoring of deforestation and forest degradation.
• Identification of forest fires and assessment of biodiversity hotspots.

3. Water Resources:

• Mapping of watersheds, reservoirs, and groundwater potential zones.
• Monitoring of river basin dynamics, glacier retreat, and flood forecasting.

4. Urban and Regional Planning:

• Urban sprawl analysis, infrastructure planning, and land-use/land-cover mapping.
• Support for smart city development through high-resolution mapping.

5. Coastal and Marine Studies:

• Monitoring of coastline changes, coral reefs, and marine pollution.
• Assessment of fisheries potential zones and ocean productivity through Oceansat data.

6. Disaster Management:

• Rapid mapping of disaster-affected areas during floods, cyclones, landslides, and earthquakes.
• Providing data for early warning and post-disaster rehabilitation under the National Disaster Management Authority (NDMA) framework.

7. Environmental Monitoring:

• Tracking air quality, vegetation health, and desertification.
• Contribution to climate change studies through long-term land and ocean monitoring.

Technological Developments

India has continuously advanced its remote sensing technology, both in terms of sensor capability and data processing. Notable technological features include:

• Multispectral and Hyperspectral Imaging: Enables detailed analysis of surface materials and vegetation types.
• Synthetic Aperture Radar (SAR): Provides all-weather imaging capability, especially useful for flood and soil moisture mapping.
• High-Resolution Panchromatic Sensors: Allow fine-scale mapping of urban and infrastructural features.
• Geospatial Data Infrastructure: Development of platforms like Bhuvan, India’s geo-portal, which provides free access to satellite imagery, thematic maps, and location-based services.

Policy and Data Accessibility

India’s remote sensing policy emphasises open and responsible access to satellite data while maintaining national security. The National Remote Sensing Policy (NRSP) ensures that government departments, research institutions, and private industries can access high-quality satellite imagery for developmental purposes.
The Bhuvan platform, developed by ISRO, provides web-based visualisation and analysis tools similar to international platforms like Google Earth but with Indian datasets. It has become an essential component of e-governance and national mapping initiatives.

International Collaborations

India actively collaborates with various international space agencies for remote sensing research and data exchange. Partnerships with NASA (United States), CNES (France), and JAXA (Japan) have facilitated joint missions, such as the SARAL-AltiKa satellite for oceanographic studies. India also contributes to global climate and environmental monitoring programmes through the Group on Earth Observations (GEO) and the Committee on Earth Observation Satellites (CEOS).

Future Prospects

The future of remote sensing in India lies in enhancing spatial, temporal, and spectral resolution while promoting real-time data delivery. Upcoming missions focus on:

• Advanced Radar and Hyperspectral Satellites for improved environmental monitoring.
• Miniaturised and Small Satellites to ensure frequent and cost-effective observations.
• Integration with Artificial Intelligence (AI) and machine learning for automated data interpretation.
• Commercialisation and Public–Private Partnerships (PPP) to boost the geospatial economy.

Remote sensing will continue to play a pivotal role in achieving India’s goals for sustainable development, climate resilience, and digital governance.