Department of Surveying and Geoinformatics

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Browsing Department of Surveying and Geoinformatics by Author "Abiodun, O. E."

Now showing 1 - 5 of 5
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    Open Access
    Establishment of an empirical geoid model for a small geographic area: A case study of Port Harcourt, Nigeria.
    (Surveying and Land Information Science, 2010) Olaleye, J. B.; Aleem, K. F.; Olusina, J. O.; Abiodun, O. E.
    This paper examines changes in land-use and land-cover pattern in Ilorin Emirate in Nigeria between 1986 and 2006. Landsat images of Ilorin Emirates at three epochs (1986, 2000 and 2006) were used. An administrative map of local governments in Kwara State and a land-use map of Ilorin were used as base maps. Global Mapper Software was used for the image enhancement; image classification was done with environment for visualizing images (ENVI) software and was later exported to the ArcGIS for further processing and analysis. The land consumption rate and land absorption coefficient was determined to aid the quantitative assessment of change. Subsequently, an attempt was made at projecting the observed land-use / land-cover for a period of 14 years ending at 2020. The result of the work shows a gradual growth in built-up land between 1986 and 2000 and this tends to grow more rapidly between 2000 and 2006. It was also observed that the change by 2020 may likely follow the trend observed in 2000 and 2006. It is recommended that the information from the results of this work should be use to optimally and effectively plan and manage the study area.
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    Open Access
    Land Use Change Analyses in Lagos State From 1984 to 2005
    (Proceedings FIG Working Week, 2011) Abiodun, O. E.; Olaleye, J. B.; Dokai, A. N.; Odunaiya, A. K.
    The physical development in an urban community and the need to control such development for economic, socio-political and environmental reasons have necessitated the requirement for geographical and statistical information relating to the amount of land that has been used and that which is remaining. Growth and physical expansion of urban settlements has occurred significantly all over the world. This growth in recent time has taken on more dramatic momentum in those areas that have come to be regarded as the “third world”. The most notorious example of urban growth in Nigeria has undoubtedly been Lagos. Lagos has become legendary for its congestion and other urban problems. Determination of this growth and knowledge of the rate of growth is essential for adequate future planning. In this work, we used ETM LandSat imagery (1984, 2001, and 2005), Lagos State administrative map, and Lagos State land use map (2007) to determine different land use uses in Lagos at different times. From this we obtain adequate information for the analysis of the changes in these areas over the years by overlapping series of classified satellite imageries. The changes observed for each year were analysed in a GIS environment. The result shows a change of other land use types to developed (built) land between 1984 and 2001. This pattern of change continued between 2001 and 2005. The result was discussed and recommendations were made on the impact of these observed changes in the local and global environment.
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    Open Access
    Land use change detection and analysis using remotely sensed data in Lekki Peninsula area of Lagos, Nigeria.
    (Proceedings FIG Working Week, 2009) Olaleye, J. B.; Abiodun, O. E.; Igbokwe, Q.
    Land use is generating worldwide interest as changes in land use are at a rapid rate and it is estimated by the United Nation's Population Fund (1999) that by the year 2025, 80% of the world's population will live in cities. Most major metropolitan areas face the growing problems of Land development; residential and commercial development is replacing undeveloped land at an unprecedented rate. Information on land in relation to how it is being used as well as changes in such land use has become a prime pre-requisite for the growth and development of any nation. Change detection involves the use of time series satellite imageries and orthophoto maps of the study area, from which Land use maps can be generated by visual interpretation or image processing. The use of remotely sensed data (satellite and aerial) to detect changes in Land use as well as precise and accurate analysis using GIS is widely preferred over other conventional survey techniques because the method is very efficient for assessing the change or degrading trends of a region. In this work, the changing pattern in Land use in Lekki Peninsula area of Lagos, Nigeria over the period of time spanning 39years is examined using a topographical map of 1964 and a Quick Bird image of 2003. A Land use map of the study area was produced using ArcGIS 9.2, which was used for the digitization and analysis. Evolution in new classes of Land use was observed. Industrial, Commercial and recreational Land use class were among the new classes of Land use present in 2003 as compared to the predominantly educational Land use class obtainable in 1964. The study also revealed a phenomenal rise in the area extent of built up areas from 40.93 hectares in 1964 to 7271.19 hectares in 2003. It is concluded that remote sensing and GIS tools provide an outstanding platform from which accurate information on Land use changes and patterns can be obtained and that Lekki Peninsula area of Lagos has experienced tremendous changes in land use in between 1964 and 2003, so, efforts should be made to regularly update available data in order to control further development.
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    Open Access
    Principal component analysis of urban expansion drivers in greater Lagos, Nigeria
    (Nigerian Journal of Environmental Science and Technology (NIJEST), 2017) Abiodun, O. E.; Olaleye, J. B.; Olusina, J. O.; Omogunloye, O.G.
    Urban expansion has been identified as a major cause of global climatic and environmental changes. Accurate and up-to-date information about urban expansion in terms of the drivers responsible for this expansion are important for long term planning and sustainable urban development. Lagos is one of the cities that have undergone rapid urban enlargement in the last few decades and, many factors have been adduced to contribute to its sprawling. Therefore, this study aims at using the Principal Component Analysis (PCA) for identifying the principal drivers of urban expansion in greater Lagos. In this study, a set of fourteen (14) drivers of expansion are considered in a multinucleic structure. A sequence of Landsat images of the study area for 1984, 2001, 2006 and 2013 was acquired and processed to six land use classes: dense, moderate urban, water, vegetation, wetland and mangrove. The study area was partitioned into 25 regular cells of 20km by 25km each from where proximate driver values were obtained. The effectiveness of each driver was tested using PCA. The results show that Land Availability accounted for 37.836% of total variance. This result of this study may form the basis for a renewed attention on land policy in the study area as a way to enhance sustainable development.
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    Open Access
    Surveyors and the challenges of digital surveying and mapping technology
    (American Association for Geodetic Surveying, 2011) Olaleye, J. B.; Abiodun, O. E.; Olusina, J. O.; Alademomi, A. S.
    The advent of digitalization has brought revolutionary changes to the methods and instrumentation of surveying and it appears that the initial training and special qualities of the surveyor are no longer a precondition for the practice of surveying. Nowadays, many tools and techniques have been developed or improved upon for the acquisition of survey data with a high degree of accuracy, flexibility, simplicity, and cost reduction. This development poses new challenges for the traditional surveyor who needs to cope with the new trend. This paper discusses a very brief history of surveying. The innovations in surveying are discussed under the following headings: land surveying, remote sensing, hydrographic surveying, map-data processing, and data communication. Some important challenges facing the surveyor due to these innovations are highlighted. The paper also attempts to identify the responses surveyors could adopt. It is suggested in this paper that adaptive learning and retraining will help the modern surveyor but the best response will be "reprofessionalization".