Surveying and Geoinformatics- Conference Papers

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Browsing Surveying and Geoinformatics- Conference Papers by Subject "Change Detection"

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  • Item
    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.
  • Item
    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.