Surveying and Geoinformatics- Conference Papers

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Browsing Surveying and Geoinformatics- Conference Papers by Subject "GIS"

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    Open Access
    The application of remote sensing and GIS technology to erosion risk mapping
    (Multidisciplinary Digital Publishing Institute, 2018) Makinde, E. O.; Oyebanji, E. I.
    Erosion is one of the major problems in Nigeria and Lagos State in particular. The objectives of this research are to identify land use/land cover changes in Eti-Osa LGA and estimate actual erosion risk using Revised Universal Soil Loss Equation (RUSLE) model. In addition, this research evaluates the perception of communities within the study area with the view of understanding the risk involved in erosion. The result showed that the sediment yield of the study was estimated to be between 0 to 48 ton/ha/yr. The estimated soil losses were higher at Eti-Osa West, parts of Iru/Victoria Island, and Ikoyi/Obalende areas recorded low losses. Land uses mostly affected by very high and severe erosion are the bare soils and the crop lands having about 3% to 4% respectively compared to the others. It was concluded that combination of rainfall, lack of cover for the surface soil, were the major causes of soil loss in 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.