Remote sensing and GIS are promising tools for handling spatial and temporal data and help in integrating them for successful planning of natural resources. Remote sensing is the science of measuring the Earth using sensors mounted on high-flying aircrafts or satellites. These sensors collect data in the form of images and provide insights for manipulating analyzing, and visualizing those images.
In a natural resource-rich country like India, management, especially of land and water, is crucial for sustainable development. Management of natural resources calls for scientific tools for timely and accurate dissemination of information. Since natural resources are not uniformly distributed and are spatially varied, it is challenging to capture the correct picture. Any kind of improvement thus requires spatial information. In natural resource management, remote sensing and GIS are mainly used in the mapping process. These technologies can be used to develop a variety of maps for vegetation, soil, street and more. However, before such maps are developed, there is a variety of data that needs to be collected and analyzed. A wide range of remote sensing applications is presented in Table 1 and it gives details of the required spectral range.
Land management: In India, the agriculture sector alone sustains the livelihood of around 50 per cent of the population (Ministry of Agriculture and Farmer’s Welfare, 2016), therefore, increase in crop productivity has been the main concern. Since, the scope for increasing area under agriculture is rather limited, advanced crop production forecasting is required for better policy making. Even though globally there have been large experiments related to agriculture assessment, in India it was first attempted by the Indian Space Research Organization (ISRO) and the Indian Council of Agricultural Research (ICAR). The experiment–Agricultural Resource Inventory and Survey Experiment (ARISE) used aerial colour photographs to estimate crop acreage in Anantapur district of Andhra Pradesh and in Patiala district of Punjab. The other major uses of remote sensing and GIS in agriculture include crop identification, stress detection, identification of planting and harvest dates, crop yield modeling, estimation of pest and disease infestation, soil moisture estimation, irrigation monitoring, soil mapping, drought monitoring, land covering, land degradation mapping and more.
Soil management: GIS is a powerful tool that is especially relevant for soil management–information which could help prioritise development actions. GIS, RS and GPS have much to offer for preparing soil fertility maps. It is widely recognized that satellite remote sensing can provide an inexpensive, rapid and effective method of data collection and production of various kinds of thematic maps. Once the soil fertility maps are created, it is possible to transform the information from Soil Test Crop Response (STCR) models into spatial fertilizer recommendation maps. Such maps provide site-specific recommendation without testing the soil. The recommendations can be obtained by an extension agent/farmer simply by locating his farm on the map. Remote sensing has evolved into an important (supplement to ground observations in the study; of terrestrial vegetation and soil.
Watershed management: A watershed is a natural hydrological unit and its management v involves the holistic linking of upstream and downstream areas. Scientists now recognize that the best way to protect natural resources is to understand and manage them on a watershed basis. Everything that is done in a watershed affects the watershed’s system (Yongsheng, 2004). Watershed management provides a way for sustainability, integrating natural resource management with communities and their livelihood. They are important as ecological units from the perspective of conservation of rainfed marginal areas enabling a sustainable living. Availability of clean water is currently being regarded as a great challenge, especially in India. With the help of satellite data and GIS: water bodies such as rivers, lakes, dams and reservoirs can be mapped in 3D formats and the data can be used in the planning of sustainable management of water bodies. Watersheds are hydrologic units that are often used as biophysical and socio-economic or political units for the planning and management of natural resources.
Urban land management: Urbanisation is important and inevitable for development, but its proper planning and management is crucial to sustenance. One of the features of GIS is multilayered mapping, which is significant for urban planning. Urban management requires layered data on a single map wherein use of remote sensing and GIS applications comes handy. This data helps municipal corporations/ town planning boards to build cities that are better organised (Patkar, 2010; Rai and Kumra, 2011).
Geographical information of a location can be managed, correlated, foreseen and disseminated through GIS. In recent times, agencies, both central and state, have recognised the utility of GIS in problem solving through reducing cost and time. It is being actively used by municipal corporations, real estate firms, community developers and public works departments to deal with aspects like health infrastructure, disaster management, security, education, culture, transport, telecommunications and electricity etc. The information systems with socio-economic data overlaid upon satellite data makes urban planning cost effective and accurate. India used to be dependent on photogrammetry for obtaining information regarding urban planning. But since March 17, 1988 with the launch of its first satellite (IRS-1A) equipped with LISS-I sensor, which could acquire data at a spatial resolution of 72.5 megapixels, the application of remotely sensed data (from various sensors) in urban and regional planning processes has gained a momentum. First-time national level, high-resolution satellite data utilisation for preparation of large scale (1:10,000) urban geospatial database under the National Urban Infrastructure (NUIS) programme is being done by ISRO for 152 towns (covering ~50,000 sq km) using high-resolution satellite data (Cartosat-IPAN and Resourcesat LISS-IV).
Forest and ecosystem: Forest cover of the world is declining at an alarming rate, but since it is a renewable resource, it can be regenerated through sustainable management. Remote sensing and GIS data can generate information with regard to forest cover and types of forest present within an area. This information is critical in the development of forest management plans and in the process of decision making to ensure that effective polices have been put in place to control and govern the manner in which forest resources are to be utilized. One of the important missions in this regard was the first national level remote sensing based mapping of the forest cover undertaken in 1983 following which the Forest Survey of India continues to publish bi-annual updates and reports.
Coastal zone management: Coastal ecosystems have high ecological significance. GIS and remote sensing data is used to study coastal ecosystem and marine living resources which include coastal habitats like mangroves, coral reefs and more. Apart from this, suspended shoreline dynamics can be studied and climatic changes leading to cyclone and sea level rise may be of special interest too.
Geology/mineral resource management: Remote sensing in mineral exploration can help miners find and evaluate deposits without having to undertake massive exploration operations. Such images are used in two key operations. Such images are used in two key ways–through mapping the geology, faults and fractures of an ore deposit and by recognizing hydrothermally altered rocks by their spectral signature.
Images are gathered either through optical sensors or through synthetic aperture sensors. Optical sensors measure the spectral data of sunlight reflected from the Earth’s surface. Synthetic aperture sensors are able to sense electromagnetic data by transmitting microwaves and receiving the back scatter waves from the Earth’s surface. Remote sensing is a valuable tool in the discovery of high-value commodities such as diamonds and gold, which are becoming more difficult to locate. While it may not show exactly where major deposits are, data gathered through sensors can be used to narrow down field surveys to smaller areas.
Expensive operations like drilling and fieldwork can be undertaken after relevant satellite based information is gathered (Kay, 2018). The greatest advancement in mineral exploration has been the ability to synthesize various forms of data. Known drill results can be integrated with topographic maps, air photos, structural maps and ore grade data. Data synthesis can greatly increase the accuracy and effectiveness of an exploration programme.
Remote sensing and GIS be used to manage the limited natural resources in an effective and efficient manner. Geospatial data is effective in the analysis and determination of factors that affect the utilisation of these resources. The technologies provide a platform through which we can generate information that can be used to make sound decisions for sustainable development of the natural resources of India.