Essay: Land use and land cover

The knowledge of land use and land cover is important for any socio-economic planning of a region. The term land use means the use of land for human activities like residential, commercial, recreational etc. while the land cover term relates to the various types of features like urban buildings, lakes, forests, meadows, snow cover etc present on the surface of the earth (Lillesand and Keifer, 1996). According to Gupta, (1991) spatial distribution of land-use/land-cover information and its change is desirable for any planning, management and monitoring programs at local, regional and national levels. This information not only provides a better understanding of land utilization aspects but also plays a vital role in the formulation of policies and program required for developmental planning. Land management strategies involving the conversion of natural forests for agricultural and industrial activities (Hammett, 1992) are the causal factor for the changes in the land use. LU/LC changes are local and place specific, collectively they are features of global environmental change. Land use modification alter the structure of the landscape and hence the functional ability of the landscape. The changes in LU/LC include loss of agricultural lands, loss of forest lands, increase of built-up urban area, increase of impermeable surface of the area etc. The study of development of LU/LC is very much useful for the city planners and policy makers (Abd El-Kawyet al., 2011).
Environmental and ecological consequences of landscape transformation are more evident in natural ecosystems where their sustainability, multi-functional role and values are threatened (Narumalani et al., 2004; Schulz et al., 2010). Human-induced land use changes and consequent enhanced greenhouse gas emissions have been considered to be the prime driving force in the global warming and changes in the climate. LU/LC dynamics and its effects on ecological and hydrological process and on human livelihood have constituted major concerns today, evident from the consideration of LU/LC change as an important climate forcing driver. In this context, understanding the process of land use changes has been vital towards mitigating the impacts of climate changes (NRC, 2005).
Urbanization is a form of metropolitan growth that is a response to economic, social, and political forces and to the physical geography of an area (Adegoke et al., 2007). Urbanization is one of the most evident global changes. The study of urbanisation has invoked interest from a wide range of experts like ecologists, urban planners, civil engineers, administrators and policy makers. Urban ecosystems arise mainly due to the intrinsic nature of humans as social beings to live together and settlements in to cities from villages. Presently the humans live in complex ecosystems called urban ecosystems. In the last 200 years, while the world population has increased six times, the urban population has multiplied hundred times. In India, unprecedented population growth coupled with unplanned developmental activities has resulted in urbanization. This has exerted heavy pressure on land and the resources surrounding them, and has resulted in serious environmental and social problems. Rapid urbanization has significant influence on different aspects of the quality of life and research in determining the patterns of urbanization and quantifying their impacts is the need of the hour. The spreading of urban areas has also resulted in loss of natural vegetation and loss of open spaces. Moreover greater infrastructure demand has arisen due to the ever increasing population. As a consequence, the planning and management process in growing urban areas has become more and more complex and difficult. A better understanding of the process of urban growth is very much required for an efficient planning and management of resources. Urbanisation is a form of metropolitan growth which includes – population growth, commercial activities, patterns of infrastructure like the construction of industrial hubs, buildings, roads, parking slots, dump yards etc. This phenomena of rapid growth and urbanization lead to uncontrolled, uncoordinated and unplanned developments within the cities which impacts to loss of open space, loss of agriculture land, deficient in basic amenities, lack of waste management, underprovided transportation network etc. Coastal zones are most exploited geographic unit of the earth. It’s easy access and resourcefulness has always attracted human activities (Anji Reddy, 2005). For ensuring sustainable development, it is necessary to monitor the continuous changes in LU/LC pattern over a period of time (Chaurasia et al., 1996).
 
The population growth and socio-economic development results in a rapid increase of urban built up area results in the change of microclimate in urban areas. The increase of urban surface temperature compared with suburban areas is called heat island. One of the major implications of urbanization is increase of surface temperature and development of Urban Heat Island (UHI). Surface temperature is increased by anthropogenic heat discharges due to energy consumption, increased land surface coverage by artificial materials having high heat capacities and conductivities, and the associated decrease in vegetation and water pervious surfaces which reduce the surface temperature through evapotranspiration.
Research in this area of environment is needed foreffective plan and neighborhood-basedheatislandmitigationstrategies, effortstoaddresssummer timeheatasa publichealth issue and thecity planners must develop phase-in additional mechanisms and implement policies to support climate adaptive strategies in the built environment. Rapid urbanization has significant influence on different aspects of the quality of life and research in determining the patterns of urbanization and quantifying their impacts is the need of the hour. Unplanned urbanization will directly affect the LU/LC of the area. Understanding the distribution of Land Surface Temperature (LST) along with spatial extent will be helpful to study the UHI and also to find out the solution for reduction of UHI. Cities located in forested regions have stronger heat islands (http://www.nasa.gov) than cities situated in other environments. It is the lack of cooling at night time rather than high day time temperature poses risk of health hazards. Thus there is an urgent need to study temperature variation of developing cities, so that a proper developmental planning in the formulation of policies could be implemented in future.
1.2 Geo-informatics
Geo-informatics is defined as the science and technology dealing with the spatial data, its capture, its classification, its storage, processing, analysis and dissemination, including the infrastructure necessary to secure optimal use of this information. These data are obtained from many sources including earth orbiting satellites, air and space borne sensors and ground-based instruments. It is processed and manipulated with state-of-the-art information technology using computer software and hardware. It has applications in all disciplines, which depend on spatial data, including geology, engineering, agriculture, forestry, navigation, environmental studies, oceanography, land development and planning of natural resources. Thus, Geo-informatics has been an important tool in man’s quest for knowledge, a motivating force for explorative spirit and an essential means for his commercial adventure. The growing demand for economic well-being and for better quality of life has put stress on the management of resources. Therefore, the resource management has to be supported by an effective decision support system, which in turn requires timely and high quality spatial information.
Geo-informatics encompasses a broad range of disciplines including Surveying, Remote Sensing (RS), Geographic Information System (GIS), Photogrammetry and the Global Positioning System (GPS). RS and GIS are considered extremely important technologies for addressing various issues related to the earth’s environment. Remote sensing is mainly concerned with the measurement or acquisition of information about an object without being in physical contact with the object under study. Remotely sensed satellite data has advantages of providing synoptic view, repetivity and capability to study large and inaccessible areas on a regional scale. Thus it forms a vital tool in natural resources mapping and monitoring and helps to hasten the decision making process at several stages of study. GIS involves the collection, integration and storage of diversified and complete information of a region in a computer system. GPS on the other hand allows us to locate our self on the ground by means of earth’s longitude-latitude system. The altitude at any point with respect to mean sea level (MSL) is measured accurately with the help of GPS. It is universally accepted fact that RS and GIS tools play a major role in different types of infrastructure development. Most of the decision taken at various levels by different development agencies is dependent on the spatial analysis of different parameters obtainable through these systems. The maps are the most important aspects of spatial analysis. Remote sensing data provides accurate maps when used in GIS environment provides excellent tool for the planner.
 
1.3 Importance of the study
Satellite remote sensing techniques proved its capability in preparing accurate LU/LC maps and monitoring changes at regular intervals otherwise it is quite difficult with traditional method of surveying. Remote sensing techniques have proved their capability to study the change detection at global and regional scales with the availability of multi-sensor satellite data of high spatial, spectral and temporal resolutions. Thus it is now possible to prepare updated and accurate land-use/land-cover map at lower cost with better accuracy and in a short span of time (Jensen and Patterson, 2001). Multi-resolution (temporal, spatial and spectral) remote sensing data available since 1970’s aid in the analysis of long term environmental changes and impacts of human induced changes in the landscape (Xu et al., 2005; Berberoglu and Akin, 2009; Yu et al., 2011). IRS-IC images are widely used to observe and model the LU/LC characteristics of the land surface (Eastman and Fulk, 1993; Ehlers et al., 1990; Harris and Ventura, 1995; Dewan and Yamaguchi, 2009). Spatially explicit temporal data helps in the inventorying, mapping and monitoring spatio-temporal processes and changes. Understanding the causal factors with these changes is essential to develop mitigation and adaptation policies to minimize future disturbances while arresting further degradation (Marcucci, 2000).
Today most of the urbanization in the world has taken place along the coastal zone with the expansion of urban areas resulted in loss of natural land cover patterns (Anji Reddy, 2005). The study of processes of urban growth is very much required for an efficient planning and management of resources. Udupi city and its surroundings are experiencing unprecedented urbanization in recent times due to concentrated developmental activities with impetus on industrialization for the economic development of the region. This concentrated growth has resulted in the increase in population and consequent pressure on infrastructure, natural resources and ultimately giving rise to increase in built up area which causes serious challenges such as local climate change, urban heat island effects, etc. The local temperature is one of the major climatic elements to record the changes in the atmospheric environment brought about by industrialization, increasing population and massive urbanization. In the present work an attempt is made to study the contribution of spatial extent of urbanization for the variation of temperature in and around Udupi Taluk and also for the UHI effect. Keeping the above in view, the present work has been undertaken to prepare the multi-date land use/ land cover maps of Udupi Taluk from multi-sensor satellite data and monitor the changes in various LU/LC classes using digital image processing techniques.
Thermal remote sensing deals with the acquisition, processing and interpretation of data acquired primarily in the thermal infrared (TIR) region of the electromagnetic (EM) spectrum. The thermal remote sensing process mainly measures the radiations ’emitted’ from the surface of the target, while in optical remote sensing we measure the radiations ‘reflected’ by the target under consideration (Sabins, 1997). All natural objects reflect as well as emit radiations in the TIR region. These radiations are far more intense than the solar reflected radiations. Therefore, sensors operating in this wavelength region primarily detect thermal radiative properties of the ground material. The realm of thermal remote sensing encompass not only the TIR but also the short wave infrared (SWIR), near infrared (NIR) and in extreme cases even the visible region also. Thermal remote sensing, in principle, is different from remote sensing in the optical and microwave region. In practice, thermal data prove to be complementary to other remote sensing data. Thus, though still not fully explored, thermal remote sensing reserves potentials for a variety of applications. In the present research work an attempt has been made to study urbanization (LU/LC) using optical remote sensing data and surface temperature variation using thermal remote sensing data of Udupi Taluk, Karnataka State, India.
UHI implication on local climate and on the natural resources necessitates appropriate strategies for the sustainable management. Studies on the phenomenon of UHI with the help of satellites used to derive LST. Currently available satellite thermal infrared sensors provide different spatial resolution and temporal coverage data that can be used to estimate LST. The advent of satellite remote sensing technology has made it possible to study UHI both remotely and on continental or global scales (Streutker, 2002). In this work, LANDSAT data, IRS LISS-III data, hyper spectral data and stereo data of Cartosat1 are used with supervised pattern classifiers based on maximum likelihood (ML) estimation. In the present research work an attempt has been made to compare the urban growth of Udupi city and its surroundings with an effort to analyze urban growth contribution to temperature variation due to UHI effect. In addition, an attempt is made to map land surface temperatures across various LC types to understand heat island effect. This study of process of urban growth is very much required for an efficient planning and management of resources.
This research focuses to analyze the contribution of the built up area growth due to change in land cover types of Udupi Taluk during the years 2000, 2006, 2010 and 2014 to the UHI using GIS technology and also an attempt to locate the spatial extent of urban heat island areas using the temperature distribution maps based on Moderate-resolution Imaging Spectroradiometer (MODIS) data of the dates March 29 (2000), March 30 (2006), March 29 (2012) and March 30 (2014) and LANDSAT 7 of March 14 (2000), LANDSAT 8 of March 13 (2014) processed using IDRISI Software developed by Clarks university lab. This is an attempt to map land surface temperatures across various land cover types to understand heat island effect. This research aims to evaluate the use of various satellite data such as MODIS, LANDSAT for indicating temperature differences in urban areas, to analyze and compare the relationship between urban surface temperature and land cover types using Geoinformation technology.
1.4 Study area
The Udupi Taluk lies in the coastal region of Karnataka state on the west coast of peninsular India. The taluk lies between 1300′ and 1330′ N latitude and 7440′ and 7500′ E longitude and covers an area of 939.40sq.km (Figure 1.1). The area is almost plain towards west and south with an undulating topography towards east and north. The general elevation of the area ranges from 20m to 100m above mean sea level. Synoptic view of the study area, as viewed by the LISS III sensor of IRS 1C satellite, is shown in Figure 1.2.
Figure 1.1: Location map of the study area (Udupi Taluk)
Figure 1.2: Synoptic view of the study area as viewed by
the LISS III sensor of IRS-1C satellite
As per provisional reports of Census India, Udupi Taluk had a population of 529,225 while Udupi metropolitan population is 165,401 in 2011 with population density being 572/sq km. Present research work has been undertaken by observing the rapid growth of population which is in turn linked with built up area via urban growth of Udupi Taluk. Agriculture is the major occupation of the people. Paddy is the dominant agricultural crop. In addition to this, sugarcane, mango, pineapple, jackfruit, pepper, beetle leaves, coconut, areca nut, cashew, etc., are grown in the region. Other occupations of the people include fishing, trade and commerce. Udupi Taluk has made good progress in industrial development especially in small-scale industries, which include automobile, electrical, and electronics, chemical, glass and ceramics, paper and printing, wood and others. (Source: Directorate of Economics & Statistics). The area has an excellent transport communication system. National Highway (N.H)-66 and Konkan railway are passing through the area, almost parallel to the west coast. Villages and habitations are connected with metalled and unmetalled roads with a network of private and public transport systems.
1.4.1 Geology of the study area
Major part of the Udupi Taluk is covered by gneisses and laterites. Enclaves of ancient supracrustals and granulites (mainly Charnockites) also occur in some parts of the taluk. Proterozoic younger dykes are scattered throughout the taluk. Laterite felsic volcanics and alluvium along beaches and river channels are major Phanerozoic formations in the taluk. Charnockites and felsic volcanics such as dacites, rhyodacites, and granophyres are restricted to few places.
The taluk is covered with three types of soils i) sandy soil ii) yellow loamy soil and iii) red lateritic soil. The sandy soils are confined to a narrow strip of the coast having width ranging from less than 100m to as much as a kilometer. The fine to medium textured sands is characterized by their extremely high rate of infiltration and act as a good recharge media for ground water. Yellow loamy soils are transported from the place of their origin and are found mostly along river banks and lower reaches of valleys. They are mostly used for tile industries. The soil type is very well suited for irrigation and shows good response to irrigation practices. Red lateritic soil is the most dominant soil type in the area. The textures of these soils vary from fine to coarse. The soil in the valleys and immediate slopes are rich in loam where as upper slopes and pediplains they are much coarser in nature. The degree of leaching undergone by this soil type is also variable.
 
The Karnataka coastal land can broadly be classified into three regions: lowland, mid-land and highland depending on the terrain features and their altitudes. Marine and estuarine geomorphic forms characterize the lowland or coastal plain region bordering the Arabian Sea. The rivers take a meandering course with wide channels and some landmasses in the centre. Such an island, a holm is locally called as kudru. These holms are fertile lands and are usually covered by coconut palms. The mid-land region is wide and has a large number of lateritic hillocks whose height ranges from 30 to 100m above the mean sea level and scrubs dominate the natural vegetation cover on them. The west-flowing rivers cut across this mid-land region and a number of wide valleys are formed. Shoulders of these valleys are used for coconut and arecanut plantations. Small mangrove formations occur within the backwaters of the rivers.
This coastal agro climatic west flowing river basin is characterized by maritime climate. It covers parts of Swarna, Madisala, Sita, Haladi, Chakra sub basins. These rivers are perennial during normal rainfall years where as tributaries and smaller streams become dry during summer. The prevailing high gradient in the hilly terrain and heavy rainfall brings great volume of water to these rivers during monsoon. These rivers join Arabian Sea and are prone to tidal effects to considerable lengths in the inland area.
1.4.2 Meteorological conditions of Udupi Taluk
The study area falls under tropical humid climatic conditions. Generally, the weather is hot and humid throughout the year. The coastal belt is hotter than the Western Ghats. The area is marked by heavy precipitation. The various climatic parameters like temperature, humidity and evaporation, wind and precipitation are briefly discussed in the forthcoming sections.
1.4.2.1 Temperature
The study area experiences a typical maritime climate with an average temperature of 27.5°C. March, April and May are the hottest months of the year. In general, the temperature gets down with the onset of southwest (SW) monsoon (June) and increases with the retreat of monsoon (September, October). Average temperatures recorded during 2000-2014 are shown in Table 1.1 and its variations graph shown in Figure 1.3.
Table 1.1
Monthly average temperature during 2000-2012 at Udupi
Month Temperature (oC)
(2000-2012)
High Low Average
January 33 21 27
February 33 22 27.5
March 34 24 29
April 34 25 29.5
May 33 25 29
June 30 24 27
July 29 23 26
August 29 23 26
September 30 23 26.5
October 31 23 27
November 33 23 28
December 33 21 27
Figure 1.3: Average temperature variations for Udupi during 2000-2012
(Source: http://www.worldweatheronline.com)
 
1.4.2.2 Humidity and evaporation
Humidity reaches maximum during the SW monsoon (June-September) due to heavy precipitation and limited evaporation. Generally evaporation rate is very low during monsoon (July-August) and it gradually increases from October and reaches the maximum in May.
1.4.2.3 Wind
Wind speed in the study area varies from 10 to 18km/hour. During June and July (first half of SW monsoon) and in October, winds are strong (16km/hour to 17km/hour). Most of the time, wind blows from S, SW and W directions between May and September. From October to January, it blows mainly from N, NE and E directions. While, between February and April, it blows from N, NE and E for about 50% of the time and from SW and W directions for the remaining 50% of the time. The land-sea breeze occasionally attains a speed as high as 20km/hour.
1.4.2.4 Clouds
Sky is densely clouded almost all the days during the southwest monsoon, which sets in the first or second week of June and continues till the end of September. The dense cloud setting usually starts in late April with the maximum cloud formation occurring in May/June. The number of heavily clouded days is only a few in the post-monsoon months of October and November. In the remaining months, sky is generally clear.
1.4.2.5 Precipitation
Precipitation greatly influences the physicochemical conditions and primary production of coastal waters by generating a large volume of water discharge into the sea. It is very crucial as it erodes and washes land and carries sufficient sediments into the sea along with inorganic nutrients and terrestrial organic load thus controlling the water quality. About 80-85% of the annual rainfall is received during the SW monsoon, about 10% during the post-monsoon season and the remainder during the pre-monsoon season (Figure 1.4). Western Ghats plays an important role in the distribution of rainfall and orographic precipitation. Compared to the coastal belt, the hill region of the Western Ghats usually receives more rainfall. Udupi Taluk gets highest annual rainfall in Karnataka state, of about 4000mm. In this coastal taluk, bulk of the rainfall i.e. over 85% occurs during monsoon season. The temporal variation of rainfall is confined to 5 to 6 months in a year.
Figure 1.4: Graph showing monthly precipitation at Udupi during 2000-2012
(Source: http://www.worldweatheronline.com)
1.5 Specific objectives
The main objectives are:
• To generate spatial databases using topographic maps and various sensors of multi date satellite imageries of Terra/Aqua, LANDSAT and IRS.
• To generate the multi-date land use/ land cover maps of the study area from multi-sensor satellite data and to monitor the changes in various land-use/land-cover classes using digital image processing techniques.
• To generate land surface temperature spatialdata base using multi date thermal satellite imageries and retrieval of air temperature of the study area.
• To analyze the spatial pattern of the land surface temperature and surface urban heat island effect in order to correlate with urbanization and various land cover types using normalized difference vegetation index as a parameter.
• To develop mitigation strategies for urban heat island phenomenon based on integrated approach of RS and GIS techniques
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