Department of Surveying and Geoinformatics
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- ItemOpen AccessLand 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.
- ItemOpen AccessRemote Sensing, A Vital Tool in Monitoring Climate Change(Proceedings of the 2nd Annual Conference of the Institute of Ecology and Environmental Studies, Ile-Ife, OAU., 2009) Omodanisi, E. O.; Salami, A. T.The impact of anthropogenic activities on the planet we inhibit has affected the climate. Humans are at risk as the earth is warming up. It is through the observation of atmosphere and hydrosphere data; and by using the latest technology such as Remote Sensing (RS) and geographical Information System (GIS) that climate change could be monitored, assessed, analysed and interpreted effectively on real time basis. This paper highlights how RS and GIS can be adopted in combating climate change.
- ItemOpen AccessGPS Derived Orthometric Height for Small Engineering Surveys(Journal of Engineering Research, Faculty of Engineering, University of Lagos., 2009-03) OLALEYE, J.B.; ISIOYE, O.A.; ABIODUN, O.E.Global Positioning System (GPS) measures heights related to the ellipsoid. GPS height differences do not reflect the direction of flow under the influence of gravity and are not physically meaningful. This makes heights from GPS of little or no use in engineering surveys and geophysical explorations, many engineering applications require heights that are related to a physically meaningful surface such as the geoid. Such physically meaningful heights are the orthometric heights. This paper reviews the different error sources affecting GPS determined heights and demonstrates the use of geometric (local) geoid model for determining orthometric heights from GPS levelling as may be required for small engineering projects.
- ItemOpen AccessOn the Optimal Method of Surface Gravity Prediction Using Different Trend Surface Algorithms(Journal of Engineering Research, Faculty of Engineering, University of Lagos., 2009-06) OLALEYE, J.B.; ISIOYE, O.A.; ABIODUN, O.E.Text attached
- ItemOpen AccessEstablishment 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.
- ItemOpen AccessProtecting Oil Pipeline Corridor and Associated Disasters in Nigeria: the Geoinformation Challenge(, Process and Plant Engineering, Special Focus on Environmental Management. Shanvik Publications Ltd., 2010) Omodanisi, E. O.; Eludoyin, A. O.; Salami, A. T.This study is an attempt to exemplify the possible application of Geoinformation technology for identifying vulnerable settlements within crude oil pipeline corridor in Nigeria. Selected communities had been affected by conflagration from bust pipelines earlier in the decade. Data used for the study were derived from Landsat ETM+ (2002) and 1:25,000 topographic map of the Amuwo-Odofin Local Government area in Lagos State. The data were processed and analysed in Erdas Imagine (version 9.2) and ArcGIS (version 9.0) software. The study showed that the oil pipeline in the study area is exposed, hence its vulnerability to vandals, whose activities resulted to the conflagration. It also revealed that a number of settlements exist within the oil pipeline corridor that probably increased the casualties in the previous disaster: The study concluded that remote sensing and Geoinformation techniques are efficient for providing for the management of pipeline corridors.
- ItemOpen AccessSurveyors 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".
- ItemOpen AccessLand 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.
- ItemOpen AccessThe effect of oil pipeline vandalization on the Mangrove Vegetation: A case study(Elsevier (Scopus) International Statistical Institute (ISI, Netherlands) Journal, 2011) Omodanisi, E. O.; Salami, A. T.; Oke, S. O.This study identified the area impacted by oil spill, explosion, and fire; and assessed the effect of the vandalization of oil pipeline on the vegetation in Ilado area of Lagos State of Nigeria. The study reveals that Rhizophora mangle (38.5 %) and Cocos nucifera (22.2 %) were the dominant woody plant species in the area while Rhizophora mangle (23.0 %) and Phoenix spp (26.6 %) were dominant in the control quadrat. The girth size-class distribution of woody plants species did not conform to the inverted J-curve structure characteristic of stable vegetation. Oryza longistaminata was the most abundant species with 38.5 % in the nine affected quadrats and Pennisetum purpureum with 32.8 % in the control. Species diversity index revealed that the control quadrat had a species diversity of 0.68 while that of the nine affected quadrats had the species diversity of 0.37. It was concluded that oil spill from vandalization and the resultant fire resulted in the reduction of mangrove vegetation and changes in its species composition and distribution.
- ItemOpen AccessSurveyors and the Challenges of Digital Surveying and Mapping Technology(Surveying and Land Information Science, American Society of Geodetic Surveying, the National Society of Professional Surveyors and Geographic and Land Information Society., 2011-03) OLALEYE, J.B.; ABIODUN, O.E.; OLUSINA, J.O.; ALADEMOMI, A.S.
- ItemOpen AccessCreation of a Cell-Based Digital Cadastral Mapping System (Digital Cadastre): A Case Study of Goshen Beach Estate, Lekki Peninsula, Victoria Island.(2011-12) Olusina, J.O.; Olaleye, J.B.; Alademomi, A.S.; Ojie, T.I.The analogue ways of land administration over the years in developing countries have brought retrogression to land development and its sustainability as a limited natural resource. The use of pencil and papers in land management is outdated and has reduced efficiency. Fast delivery of land related products from government authorities and the private sector takes weeks or months. The need for transformation from analogue approach (traditional cadastre) into the digital technology era (digital cadastre) in order to derive the seemingly unlimited benefits is pertinent. Digital cadastre enhances land transaction activities to be conducted in a business manner. Similarly, land subdivision or boundary redefinition, land registration and land marketing are achieved with better accuracy. This paper discusses the need to introduce a national Cell-Based Digital Cadastral Mapping System model (DCMS) that spans from the federal level down to the states, local governments and the private enterprises such as estate surveying firms. That is, from geodetic accuracy to tertiary (micro) accuracy in order to achieve a seamless nationwide digital cadastre coverage. At the micro level of creating DCMS, Goshen Beach Estate in Lekki Peninsula was used as a case study. The use of Unique Parcel Identifier (UPI) and Spatial Indexing were discussed. Quasi-Land analysis was carried out. From this study, it was discovered that productivity and delivery of land information are enhanced; opportunity of multiple users guides against data and resources duplication; and legal, technical (organizational and technological) and financial issues are better tracked and tackled using DCMS.
- ItemOpen AccessAn Algorithm for Least Squares Computation Using the Manifold and Hilbert Space Dialectics(Theoretical Mathematics & Applications, International Scientific Press, 2012-03-12) OLALEYE, J.B.; ABIODUN, O.E.; OLUSINA, J.O.The method of least squares is widely used in numerical analysis of data in all applied quantitative fields. Although there is only one least squares criterion, several schemes have been used for its implementation. The manifold approach treats the entire least squares process, including the representation of the variables, the model formation and the computations, in terms of manifolds. A manifold is a group of variables or functions taken together and treated as an entity in the computation process. This paper presents the least squares optimization on the manifolds and shows that the express formation and solution of the usually formidable normal equations can be avoided by employing the Hilbert space axioms and methods in the Euclidean space generated by the axial manifolds. The sequential and systematic approach of the new scheme, the preservation of the group structure and the analytical insights it provides for understanding the fundamental geometry of the least squares problem, all of which are demonstrated in the sample applications presented, support the conclusions that the manifold approach is less daunting, requires less core storage space and facilitate better understanding of the problem and the solution.
- ItemOpen AccessRemote Sensing of Vegetation Stress and Indicators(Proceedings of Global Geospatial Conference 2013. Addis Ababa, ETHIOPIA, 2013) Makinde, E. O.; Salami, A. T.The study used spectra indicators to determine the health status of polluted vegetation. Global Positioning System with an accuracy of ± 5m were used to identified stress areas. The identified impacted areas were mapped out for the field and Multispectral satellite image (RapidEye, 2009 and 2011) study. Control plot was established in relatively unstressed area. Spectra measurements were taken using hyperspectral Analytical Spectral Device (ASD) Handheld2 Spectrometer within a field of view (FOV) of 25°. Spectral indicators were calculated and the relationship between these spectral indices and chlorophyll content of the vegetation were determined. The correlation coefficients of 0.5 and higher were observed in plot B and Plot C of Ogun. Plot C of Ogun of had a range of 0.6 -0.83 rho at p>0.01 for all the indices. The result of the Analysis of Variance identified the best ratio and vegetation indices that significantly differed between less stressed (control) and more stressed (impacted) plots. RedEdge indices had an F-ratio of 4.564 at p<0.01 and 2.731 at p<0.1 for VOG1. The image data analysis showed that there was a direct relationship between different pollution levels and the chlorophyll content of F-ratio 325.8 (p< 0.0001) and 93.36 (p < 0.001) for 2009 and 2011.The study concluded that vegetation impacted by oil spill pollution are unhealthy.
- ItemOpen AccessGeoidal Map and Three Dimension Surface Model(International Journal of Computational Engineering Research (IJCER), Vol. 2. No. 4, pp 52-58., 2013) Olaleye, J. B.; Olusina, J.O; Badejo, O.T; Aleem, K.FGeoidal map depicts the geoid configuration of the area under study. Data acquisition for the production of such maps has been very tedious, time consuming and expensive with the use of classical and conventional geoid determination methods. "Satlevel" Collocation is a new method of geoid determination in which the ellipsoidal height from any satellite based system is combined with orthometric height from geodetic levelling to model the geoid. The method enables the geoid to be determined in patches. Geoid so determined can be applied with ellipsoidal height to get orthometric height which height users always prefer. In this work, "Satlevel" Collocation model along with the user‟s interactive computer program “Orthometric Height on Fly”, were used to generate geoidal values in part of Port Harcourt metropolis. The generated data was used to produce the Geoidal map of the study area using SURFER software. The map was overlaid on the Local government map of Rivers State of Nigeria. The production of Geoidal map from "Satlevel" Collocation is easier than the conventional methods, when the initial geoidal coefficients have been determined. This method can be extended to other parts of Nigeria and the world at large.
- ItemRestrictedResultant land use and land cover change from oil spillage using remote sensing and GIS.(Elsevier (Scopus) Research Journal of Applied Sciences, Engineering and Technology, 2013) Omodanisi, E. O.The spill of oil into the environment threatens the existence of vegetation. This study identified the coastal area of Lagos impacted by oil spill, explosion and fire; using Landsat ETM+2005 and Ikonos 2007 and evaluated the effect. Subsequently, geo-spatial database was created for monitoring of oil pipelines Right of Way (ROW) in the area. The biggest land use land cover changes were the high forest and the light forest classes of mangrove vegetation by 22.2 and 15.5% respectively. The control quadrat sampled had the highest species diversity index of 0.6758 compared to the others. The study concluded that oil spill had affected the land use land cover as well as provided oil spill emergency response centres sites as a Spatial Decision Support System (SDSS) for oil pipeline management.
- ItemOpen AccessA multi-perspective view of the effects of a pipeline explosion in Nigeria.(Elsevier (Scopus) International Journal of Disaster Risk Reduction, 2014) Omodanisi, E. O.; Eludoyin, A. O.; Salami, A. T.Vandalisation of petroleum pipelines is a major cause of pipeline fire disasters. However, except the number of deaths recorded, little information of the effects of such disasters on the environment is often reported in developing countries, and post-disaster remediation process is thus usually unmonitored or ineffective. This study investigated the effect of a major pipeline disaster in a rural environment in Nigeria from multi-date satellite imageries (orthophoto map, Landsat Enhanced Thematic Mapper Plus, ETM+ and IKONOS), social and ecological surveys. Results showed that some of the affected settlements were within the pipeline corridor before the disaster, and pipeline vandalisation was encouraged by one or more cases of faulty and exposed pipeline, deficient pipeline monitoring system, sabotage and readily available markets for siphoned oil. Ecological effects include loss of about 200 ha of vegetation resulting into significantly lower woody and herbaceous plant species in the affected regions than the adjacent plots. Significant proportion of the survivors also reported lower quality of groundwater (well water), air and streams, health problems (mainly abdominal pain) after they drank the well water and destruction of their crops and farmlands. The study concluded on the need for enforcement of the right-of-way laws on pipelines in Nigeria.
- ItemOpen AccessThe Perception of Communities Prone to Environmental Degradation(2nd Africa Regional Conference Technical Proceedings. Organization for Women in Science for the Developing World (OWSD) Organized under the Auspices of: University of Energy and Natural Resources (UENR), Sunyani, GHANA., 2014) Makinde, E. O.The activities of man affect the environment which in turn influences the climate. This study assesses these human activities by determining the perceived impact of oil spill and its attendant explosion and fire has on the environment. This study was carried out in Lagos, covering some coastal settlements in Amuwo-Odofin Local Government Area. Landsat 30 m (ETM+) of 2005 and Ikonos 10 m of 2007 were the satellite images used which were subjected to digital image processing and analysed. Also, the study area was divided into 3 strata and convenient sampling technique was used on each stratum to administer 200 copies of questionnaire for data collection which were analysed. The results showed that there was a decline in the high and light forested areas, respectively between 2005 and 2007. Furthermore, the result revealed that educational exposure affected the way the community perceived the impact of oil pipeline vandalization on the vegetation and strategies to prevent pipeline vandalization (F=2.8-5.9; p<0.05). It was concluded that oil pollution resulted in the reduction of vegetation while educational level affected the way in which the impact of the pollution was perceived.
- ItemOpen AccessAn Assessment of the spectra characteristics of vegetation in south western Nigeria.(IERI Procedia, 2014) Omodanisi, E. O.; Salami, A. T.This study assessed the status of oil spill induced stress in the vegetation in Lagos and Ogun States, in the South West of Nigeria. The locations of oil spill impacted areas were identified on the field using information from the locals and a Global Positioning System with an accuracy of ± 5m and subsequently identified on the 5 m resolution RapidEye satellite image of 2009 and 2011. Field spectra were collected using Analytical Spectral Device (ASD) Handheld2 Spectrometer. The results showed varying spectral measurement of the impacted and the control. Indices were then used to distinguish less stressed from stressed vegetation which were statistically higher at F-ratio 4.825 (p < 0.01) and 3.194 (p < 0.01) in Lagos State; and 4.564 (p < 0.01) and 2.731 (p < 0.1) in Ogun State. It was concluded that oil spill had changed the spectra characteristics of impacted vegetation.
- ItemOpen AccessUrban Sprawl Analysis and Transportation Using Cellular Automata and Markov Chain(Physical Science International Journal, Sciencedomain International, 2014-01-10) OLUSINA, J.O.; ABIODUN, O.E.; Oseke, J.I.
- ItemOpen AccessTidal Charateristics and Sounding Datum Variation in Lagos State(2014-07) Badejo, O.T.; Olaleye, J.B.; Alademomi, A.S.The need for water level monitoring has increased over the years. Water level monitoring is among other things useful for oil and gas exploration and exploitation activities, and construction of ports and harbour works. The mean sea level for Lagos, Nigeria is referenced to the Lagos datum situated at the Office of the Surveyor General of the Federation at Lagos Island. This paper examines correlation and variation in the mean water levels and sounding datums for twelve water bodies in Lagos State. Water level observations were taken with the aid of tide gauges for twenty nine days at 12 tidal stations strategically situated within Lagos State. The mean water levels and other tidal characteristics for the various water bodies were calculated from the observed tidal observations from the twelve tide gauge stations. The tide gauge station at the Lagos Harbour has a known chart datum. Sounding datums were therefore determined for the eleven tide gauge locations by sounding datum transfer technique using the Chart datum at the Lagos harbor. The result from our study shows that there are variations in the tidal characteristics of the various water bodies in Lagos State. There is also a need for the harmonization of the various tidal datum in Lagos State.
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