One of the emerging scenarios in Indian geography in recent years has been the use and application of Remote Sensing and GIS in geographical studies and researches. It has opened a new research frontier in Indian geography.
Weather and Climate Change:
New developments are taking place in estimating sea surface temperature and modeling the methane emission using MODIS, the multipurpose INSAT 3A provides vital information for a detailed monitoring of the weather and an accurate forecasting.
The installation of 100 data collection platforms (DCPs) and the Disaster Warning Systems (DWSs) has been done for transmitting methodological data on the one hand and for tracking the path of cyclone on the Andhra Coast on the other hand.
They also provide information imageries. Significant information has been consistently received at the meteorological headquarters and centres of global climatic change on forest diversity from the satellite signaling and imageries.
Space Application Centre is continuously monitoring glaciers in order to observe climate change impacts. Remote sensing data are being used for mapping potential glacier lake outburst floods (GLOF) in the Himalayas.
The most frequent applied areas of remote sensing in India is the study of Earth’s subsurface and surface features. Aerial photographs are an effective tool for geological, geomorphological, relief and hydrological studies and land-use mapping. Geomorphic units have been identified based on interpretation of the aerial photo
graphs and the Survey of India’s topo-sheets and the LANSAT imageries in the various regions like Pali district, Jodhpur district, Luni basin and Tripura state.
These geomorphic units have different physical potential and provide a sound base for land-use planning. Other application includes remote sensing study in identifying wind erosion areas. Remote sensing techniques have been applied for geomorphic and land-use mapping of larger areas of Assam.
Based on aerial photographs, a study of Hiran catchment (Jabalpur district), highlights the physical and hydrological characteristics of the area, using quantitative analysis for land resource development and management. GIS has been used for soil productivity assessment and mapping. Drought monitoring is an important aspect of satellite monitoring in Maharashtra.
The National Remote Sensing Agency (NRSA) carried out a survey for soil association mapping, land degradation and ground water exploration to aid drought relief in Bundelkhand region of Uttar Pradesh. A GIS has been initiated by the Geological Survey of India for locational and distributional identification of various kinds of rocks and mineral deposits.
Hydrology and Water Resources:
Targeting ground water in hard rock, using remote sensing and GIS, is a recent phenomenon in hydrological science. In India, remote sensing is used for monitoring the aspects such as measurements of evapo-transpiration, measurement of water surface roughness, rainfall distribution and infiltration, ground water discharge and salt content of water and light absorption.
Aerial photographs have been utilised to collect information regarding water storage, season and long-term fluctuations of lake and river surface aerial extent, assessment of underground and soil moisture. Estimation of surface temperature of snow has been assumed through GIS technology.
The weather satellite imagery is usually used to monitor ice and snow cover conditions providing important inputs for water management and flood prediction. In recent years, microwave sensor data is being used for flood monitoring during cloud cover condition.
The sustainable benefits from coastal marine resources require considerable improvement in the application of remote sensing imageries to improve both utilisation and management of these resources. The launching of the OCEANSAT-1 satellite has brought in significant improvement in the ocean monitoring.
Forest and Biodiversity:
Assessment of grassland and their changes with time has been greatly facilitated by using remote sensing and GIS technology. It is through remote sensing that the actual forest covers of India were known through findings of satellite data analysis. The first attempt to categorise forest cover types by computer analysis of Landsat data was done in 1978 for Nagaland.
In a study conducted by NRSA, the satellite digital image covering entire Periyar-Thodupuzha drainage basin was analysed. Apart from forest land classification, stock mapping and volume estimation, remote sensing is also used for damage assessment and fire detection, which is a common feature of Indian forests. GIS is used in biodiversity conservation plan.
The Forest Survey of India prepared forest cover type and land-use maps on 1:50,000 and 1:63,360 scale by interpreting medium to small scale panchromatic aerial photographs for about 4,20,000 sq.km2 in India. The main application of remote sensing in forest management has been for timber harvest planning and monitoring of logging and deforestation – Digital Elevation Model (DEM) has been used to prepare terrain complexity map. Potential fishing zones are being mapped from the data collected through satellites.
Land-Use/Land Cover Mapping:
Land information system has been developed to assess and manage the land resources of any area. Using IRS-LISS-1 data in 274 districts through visual interpretation and 168 selected districts through digital techniques, agro climatic zones are being analysed. For the first time, two season satellite data both for Kharif and Rabi seasons are used to precisely estimate the agricuitural land in Kharif and Rabi seasons. Landsat data have been used intensively for mapping.
Recently, under this programme, one of the projects refers to changes on the land use because of urban spread, while another project emphasises on industrialisation in Ahmedabad—Vapi regions, Gujarat, and Chindwara district, M. P. A detailed land capability classification is being conducted using remote sensing and GIS technology, especially for highlands and Himalayan regions, prone to land degradation to be used for the formation of integrated land use plan.
The arid zone monitoring includes agricultural improvement and desertification study. The land-use land cover change through GIS technique is very significant in analysing the dynamics of land-use change. Various remote sensing and GIS layers are also being used for mapping urban heat islands.
Increasing demands in urban planning and management sectors call for coordinate application of remote sensing and GIS for sustainable development of urban area. Availability of high resolution data form IRS-1C and ID satellite has revolutionised the process of thematic mapping and spatial- data base creation, especially in the context of urban sprawl and regional planning.
Other application includes use of remote sensing in infrastructure development, urban sprawl mapping, regional planning for air and noise monitoring network, development or road monitoring and management systems and silting sanitary landfills, etc.
Monitoring of Natural Hazards and Disasters:
The remote sensing data, particularly from satellites, have unique capability to monitor the condition of atmosphere and on Earth’s surface. The images from an environmental satellite in conjunction with the conventional data help in monitoring severe connective situations, e.g. cyclones and storms, responsible for large-scale destruction. The visible, infra-red and enhanced infra-red images are utilised to estimate rainfall in sensitive areas. The hydrological and meteorological data transmission from the data collection platform (DCP) system is valuable input for planning flood control and protection measure.
Drought monitoring is an important aspect of satellite monitoring in Maharashtra. The study for the period 1986-89 provides a valuable data-base to study annual biomass production, agro climatic zoning and rain-use efficiency in addition to its use in drought monitoring.
In the year 1986, the NSRA completed the survey and mapping of wastelands in India using Landsat satellite data. Flood plain zonation is a key tool in managing the disaster in the various parts of India. Satellite imageries are also being used for assessing the impact of flood on biodiversity, particularly in Kaziranga National Park.
There is no doubt that Indian geography has made steady progress since 1947. Nevertheless, branches developed appeared and disappeared, and then again re-appeared on the horizon. This has been the story of ups and downs that Indian geography has witnessed and experienced during this long period of history.’ B. Thakur once remarked (1994), ‘Indian geography appears to have borrowed much from the western models, and there is a general lack of tendency among the Indian geographers to develop indigenous models’.
There is truth in this statement. Indian geography has progressed very much in the last 20 years, and various branches have developed, and some are on the way of emerging, with remote sensing and GIS techniques being incorporated not only in physical geographical studies, but also in various branches of human geography. But the real problem is that we still stick to western models, theories and laws, and continue with traditions that the geographers of the first generation had established 60-years ago.
Problems have changed, geographical phenomena have changed in the past 60 years, but we have not changed. The tendency to rely upon western traditions notwithstanding, the development and progress of Indian geography, necessarily stands in the way of the development of indigenous Indian geography.