Chukwuma John Okolie

University of Cape Town | UCT · School of Architecture, Planning and Geomatics

Introduction: Vaccines alone do not control pandemics, but vaccinations. The hope of COVID-19 pandemic control is hinged on vaccinations and other public health measures. This systematic review/meta-analysis (SR/MA) investigated the factors that inform coronavirus vaccine uptake globally in an attempt to improve COVID-19 immunization. Method: The P...

Flooding is one of the most prevalent natural disasters affecting people worldwide. Flooding is a devastating natural disaster in Malaysia regarding the number of people affected, socioeconomic damage, severity, and scale of the impact. Urban flooding is currently a major concern due to the possible consequences and frequency with which it occurs i...

Besides its paramount role to life and human survival on the earth, water also plays a crucial role in understanding certain earth processes. Water can be quite hazardous, whether in a surplus state or in a deficit state. The former presents as flood, while the latter presents as drought. Nigeria, unfortunately, over the years has been shown not to...

The interrelationships between air quality, land cover change, and road networks in the Lagos megacity have not been explored. Globally, there are knowledge gaps in understanding these dynamics, especially using remote sensing data. This study used multi-temporal and multi-spectral Landsat imageries at four epochs (2002, 2013, 2015, and 2020) to ev...

Urban development will likely continue to increase in suburban areas to cater for the growing human population. In Nigeria, the relevant analysis of these urban developments is not well documented. This article presents spatiotemporal datasets for analysing urban developments in a suburb of Kuje, an Area Council within the Federal Capital Territory...

Google Earth (GE) is the most popular virtual globe in use today. Given its popularity and usefulness, most users do not pay close attention to the positional accuracy of the imagery, and there is limited information on the subject. This study therefore evaluates the horizontal accuracy of historical GE imagery at four epochs between year 2000 and...

To assess the quality and performance of ALOS World3D-30m (AW3D30-30m) Digital Elevation Model (DEM) on the Nigerian terrain , this study evaluates the accuracy of three versions of AW3D30-the average (v1.1AVE) and median (v1.1MED) products of version 1.1, and version 2.1 (v2.1). Tested against highly accurate Ground Control Points in Lagos and the...

Despite the increasing availability of remote sensing imagery, spatial data of adequate spatio-temporal resolution for urban development analysis and urban planning remains inadequate in some places. Structure-from-Motion (SfM) photogrammetry provides a low-cost option to generate such data at the desired spatial resolution. This study thus present...

In flood mapping, it is often required to combine a variety of information sources and techniques. This integration can yield an optimal, multi-perspective and comprehensive assessment of the flood susceptibility in a target area such as the city of Douala in Cameroon. Available facts indicate that Douala is highly susceptible to flood especially i...

Digital elevation models (DEMs) have wide applications in cartography and are the most common basis for digital relief maps. The 30m resolution Copernicus GLO-30 and ALOS World 3D (AW3D) DEMs have been released to users worldwide for applications that include cartographic modelling, topographic mapping and hydrological analysis. The terrain represe...

In recent years several volcanic eruptions have made headlines for their significant economic and humanitarian costs. Notably these include the eruptions of Cumbre Vieja (La Palma, Spain) and Hunga Tonga-Hunga Ha'apai (Fonuafo’ou, Tonga). Both eruptions disturbed not only the human population living around them but also the natural ecosystem, leadi...

Digital elevation models (DEMs) have wide applications in cartography and are the most common basis for digital relief maps. The 30m resolution Copernicus GLO-30 and ALOS World 3D (AW3D) DEMs have been released to users worldwide for applications that include cartographic modelling, topographic mapping and hydrological analysis. The terrain repres...

The extraction of mangrove forests from satellite imagery is usually accomplished using image classification algorithms. Recently, the mangrove vegetation index (MVI) was developed for rapid and accurate mapping of mangrove extent from remotely sensed imageries. In this study, we combine two techniques (random forest classification and the MVI) to...

The horizontal accuracy of historical Google Earth (GE) images at four epochs between the years 2000 and 2018, and the vertical accuracy of its elevation data within Lagos State, in Nigeria, are respectively evaluated by comparison with a very high–resolution digital orthomosaic and comparison with 558 ground control points. Two readily available 3...

The need for water security in different regions of the world has led to the deployment of remote sensing (RS) and geographic information systems (GIS) as decision support tools with geophysical methods. In this study, the remote sensing, geospatial and aeromagnetic data were integrated for mapping the groundwater potential at the University of Ilo...

This study aims to assess the overall adequacy of Landsat 8 satellite imagery for the derivation of shallow water bathymetry, with cost and timely benefits.

The interrelationships between air quality, land cover change and road networks in the Lagos megacity have not been explored. On a global level, there are knowledge gaps in understanding these dynamics, especially with regard to the use of remote sensing data. A comprehensive study of aerosol and particulate matter distribution is required for seve...

Structural trends in the earth's crust can be detected in the form of lineaments and may be useful in several environmental applications such as mineral exploration and hydrogeology. In this study, structural lineaments in the Gongola basin of Northern Nigeria were mapped using two approaches-the analysis of gravity data and the processing of Lands...

The remote sensing community has identified data fusion as one of the key challenging topics of the 21st century. The subject of image fusion in two-dimensional (2D) space has been covered in several published reviews. However, the special case of 2.5D/3D Digital Elevation Model (DEM) fusion has not been addressed till date. DEM fusion is a key app...

In recent times, there has been renewed interest in understanding the dynamics of land cover change and its relationship with several environmental parameters. This study assesses the interrelationship between land surface temperature (LST), normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI) and land cover ch...

The terrain representation and hydrological correctness of DEMs can be improved through fusion, but very few researchers have demonstrated this. In this study, we compare watersheds and drainage networks delineated from Copernicus GLO-30 and AW3D DEMs, a fused version of both DEMs, and a 10m aerial LIDAR DEM. The DEMs were co-registered, and the LI...

The 20m SPOT DEM (Digital Elevation Model) was acquired by the Office of the Surveyor-General of the Federation (OSGoF) in Nigeria for use in topographic mapping. A localized assessment of the DEM is needed to validate its stated accuracies as it is well known that the vertical accuracy of global DEMs varies in different landscape contexts. Hence,...

Analysis of the dynamic relationship between traffic accident events and road network topology based on connectivity and graph analytics offers a new approach to identifying, ranking and profiling traffic accident high risk-locations at different levels of space and time granularities. Previous studies on traffic accident hot spots have mostly adop...

Google Earth is the most popular virtual globe in use today. Given its popularity and usefulness, most users do not pay close attention to the positional accuracy of the imagery, and there is limited information on the subject. This study evaluates the horizontal accuracy of historical GE imagery at four epochs between year 2000 and 2018, and the v...

Digital Elevation Model Fusion - Review and Ongoing Work

Several studies on traffic accident hot spots have adopted spatial statistics and Geographic Information Systems where spatial point patterns are modelled solely on spatial dependence without consideration of the temporal dependence of the events. This could lead to under-estimation or over-estimation of results because of the temporal aggregation...

Information on the historical patterns, seasonal variation of river flows, and flood frequency necessary for flood mitigation in the Adamawa catchment are limited. In this study, river flow and water stage time series for stations within River Benue reaches were analysed and peak flows were computed using the Weibull formula. The stage time series...

There is little information on the improvement achieved across all versions of ASTER GDEM in terms of vertical accuracy. This study assessed the vertical accuracies of all three versions in Turkey and Nigeria based on the mean error, root mean square error, mean absolute error, average relative error, residual dispersal patterns and combined error...

In recent times, there has been renewed interest in understanding the dynamics of land cover change and its relationship with several environmental parameters. This study assesses the interrelationship between land surface temperature (LST), normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI), and land cover c...

Remotely acquired gravity data from satellite gravimetry is integrated into the study to investigate crustal deformation in the Niger Delta Basin. The Niger Delta Basin is a well-documented example of a passive margin delta that has gravitationally deformed. The gravity-driven deformation has not been fully understood, and new trends may be emergin...

The remote sensing community has identified data fusion as one of the key challenging topics of the 21st century. The subject of image fusion in two-dimensional (2D) space has been covered in several published reviews. However, the special case of 2.5D/3D Digital Elevation Model (DEM) fusion has not been addressed till date. DEM fusion is a key app...

The 20 m SPOT DEM (Digital Elevation Model) was acquired by the Office of the Surveyor-General of the Federation (OSGoF) in Nigeria for use in topographic mapping. A localized assessment of the DEM is needed to validate its stated accuracies as it is well-known that the vertical accuracies of global DEMs vary in different landscape contexts. Hence,...

The interpretation and analysis of remotely sensed data for land cover change detection can be enhanced with the use of vegetation indices. This study used Landsat imageries to assess the relationship between the normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI) the soil adjusted vegetation index(SAVI), and land cov...

Noise Exposure Noise Pollution Perception Health and Wellbeing This study assessed age and gender differences in the perceptions and health impacts of noise exposure within the University of Lagos main campus. An opinion pool of staff and students (male and female) was sampled with an online questionnaire survey that inquired about the likely contr...

Third Mainland Bridge GNSS Survey Deformation Monitoring Geodetic Network Bridge Collapse There have been several cases of bridge collapse all over the world leading to loss of lives and valuable infrastructure. Such incidents can be averted if bridges are properly monitored through deformation surveys. This study aims at establishing a geodetic ne...

Climate change is undoubtedly one of the greatest existential threats to humans. This threat is continuously being aggravated by continuous urbanization which leads to the rapid change of land cover profoundly affecting biodiversity and ecosystem function as well as local and regional climate. This study assesses the variation of land surface tempe...

Land Cover Change Land Cover Prediction Neural Network Cellular Automata Markov Chain This study investigates the spatio-temporal variations in land cover within the Anambra River Basin of southeastern Nigeria at three epochs: 1987, 2000, and 2018. The land cover scenario for 2030 was also predicted. Land cover was extracted using neural network cl...

Structure-from-Motion (SfM) Photogrammetry is a valid alternative to traditional photogrammetric methods. This study presents a simplified approach for mapping and monitoring of urban developments in a section of Kuje Area Council in Abuja, Nigeria, utilizing SfM Photogrammetry alongside Google Earth Historical Imagery. The capture of the UAV image...

Location influences Infrastructural facilities' importance, efficiency, and performance. This study involves locational analysis of infrastructural facilities in twenty purposively selected oil and non-oil producing rural communities of Akwa-Ibom State. Coordinates of infrastructural facilities were acquired using a handheld Global Positioning Syst...

The changes in mangrove areal distribution can result in significant changes in the coastal ecosystem. In order to curb this, conservation efforts have been adopted especially in developing nations due to the ease of implementation of some of those initiatives. Despite their positive impacts, poor monitoring and evaluation of these initiatives have...

In the face of increasing exposure to various environmental pollutants, the peculiarity of noise has made it to pervade even well-structured societies. This study assessed the health impacts of noise exposure within the University of Lagos main campus. An opinion pool of staff and students was taken with an online questionnaire survey that inquired...

This study applies Geographic Information System (GIS) and Analytical Hierarchy Process (AHP) to assess flood vulnerability in the Adamawa Catchment of Nigeria. Seven criteria (drainage, rainfall distribution, geology, land cover, elevation, slope, and soil) were analysed, and a pairwise comparison matrix was constructed. The analysis resulted in a...

Kingdom 3 Nigerian Navy, Nigerian Navy Hydrographic Office (NNHO), Nigeria Keywords ABSTRACT Lagos harbour Bathymetry Commodore Channel Kriging Dredging The Commodore Channel in Lagos State is located at the seaside entrance into the Lagos Harbour thus exposing it to the action of dynamic coastal forces such as high waves, tidal currents, and storm...

Remote sensing Landsat 8 Stumpf's model Shallow water bathymetry Lagos There is high demand for the seabed topography of water bodies. The shallow nature of some waterbodies makes it difficult to deploy the conventional bathymetry method, that is the use of echo-sounders on a vessel. Under these conditions, remote sensing methods thrive with signif...

According to the United Nations Office for Disaster Risk Reduction, 1 the number of global weather-related disasters in the past decades has been estimated at 90% of the total number of disasters. These are likely to increase in severity and frequency with current and forecasted global climate changes. Disaster risk monitoring using space technolog...

Air pollution is one of the environmental problems confronting growing cities and is currently the challenge faced by many developed and developing countries. The aim of this study was to monitor the varying concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), particulate matter (PM1.0, PM2.5 and PM10), polycyclic aromatic hydrocarbons...

The continuous monitoring of the relationship between land surface temperature (LST) and land cover change is imperative for an inquiry into the potential impact of LST on human well-being, including urban outdoor thermal comfort in Lagos State, Nigeria. Using Landsat imagery, this study assessed land cover and LST changes from 1984 to 2019. Land c...

Drones can be used to generate information about land and natural resources, in ways that fit with sustainable land management methods.

Lagos State, which is home to Lagos metropolis and the eighteenth largest urban agglomeration in 2018 in the world, has been characterized by rapid urbanization. An earlier study of the eastern segment of the state revealed dramatic urban growth in previously rural local councils where it replaced mostly ecological assets. For a statewide view of t...

Digital elevation models provide 3D visualisations of the earth’s surface for addressing key global challenges such as disaster risk, insecurity and climate change, and are very important for sustainable development. Due to cost limitations, most African countries do not have digital elevation models that cater to their peculiar landscapes. This re...

Gullies and other forms of erosion have been the greatest environmental problem and catastrophe in most high- and low-income countries. The challenge posed by soil erosion has compromised agricultural productivity, environmental biodiversity and food safety for the world's population. It is important to identify vulnerable areas to soil erosion in...

The computation of geodetic coordinates is the basis of geodetic surveying and foundation to modern techniques for geodetic network analyses and design of integrated survey schemes for monitoring and detecting structural deformations. The positional accuracy achievable by Direct and Indirect models of geodetic position determination depends on the...

In most of Nigeria’s rural communities, land holdings are small and uneven; and this impacts significantly on their mechanisation potentials. This fragmented nature of the farmlands also inhibits the creation of an effective land market. This study utilised a digital orthomosaic generated from an Unmanned Aerial Vehicle (UAV) survey in evaluating t...

In this study, we investigated flood-prone areas along the flood plains of River Ogun in southwest Nigeria.

The aim of this study is to monitor the changes in the channel's bathymetry using data on water depth from a time series of bathymetric charts covering the channel at different periods.

The aim of this study is to carry out a desertification risk assessment of Bauchi State, Nigeria using the MEDALUS model

This study employed Remote Sensing ( and Geographical Information System ( techniques in carrying out watershed based surface runoff estimation for Lagos and Ogun States

This research demonstrates the use of watershed morphometry combined with weighted sum analysis ( to estimate the susceptibility of soil erosion of sub watersheds of the Imo River Basin in South Eastern Nigeria using satellite based remote sensing data and geographic information system ( analysis

Using change detection analysis and the Cellular Automata Markov Chain model applied on Landsat imagery of three periods 1987, 2000 and 2018 this study assesses the spatio-temporal changes in land cover and predicts the future scenario for 2030 within the basin

This study involves a locational analysis of infrastructural facilities in oil and non-oil producing areas in twenty rural communities of Akwa-Ibom State.

Nigeria reported its first case of the novel coronavirus (COVID-19) infection in February 2020. The COVID-19 attained World Health Organisation (WHO) pandemic status a month later. As at 13th August, 2020, over 48000 cases have been confirmed in the country with at least 950 deaths. Katsina State recorded its first death on the 7thof April, 2020. S...

This study examined the geographical distribution of Police Stations and facilities in part of Kaduna Senatorial Zone II, Kaduna State. Mobile Topographer Application was employed to obtain geographical coordinates of the police stations and some outposts; while the attribute data related to police personnel in each station were obtained through ad...

This study assessed the knowledge and perceptions of noise levels within the University of Lagos main campus

Lekki Peninsula, which is home to the nouveau riche, is one of the barrier islands of the barrier-lagoon system of the Lagos coastline. The peninsula has been undergoing rapid urbanization since 1980 in total disregard of its physical characteristics. This study assessed landscape dynamics in the peninsula from 1984 - 2014 and evaluated risks to de...

Introduction: the spread and diffusion of COVID-19 undoubtedly shows strong spatial connotations and alignment with the physical indices of civilization and globalization. Several spatial risk factors have possible influence on its dispersal trajectory. Understanding their influence is critical for mobilization, sensitization and managing non-phar...

The continuous monitoring of the relationship between land surface temperature (LST) and land cover change is imperative for an inquiry into the potential impact of LST on human well-being, including urban outdoor thermal comfort in Lagos State, Nigeria. Using Landsat imagery, this study assessed land cover and LST changes from 1984 to 2019. Land c...

Unmanned Aerial Vehicles (UAVs), commonly known as drones are increasingly being used for three‑dimensional (3D) mapping of the environment. This study utilised UAV technology to produce a revised 3D map of the University of Lagos as well as land cover change detection analysis. A DJI Phantom 4 UAV was used to collect digital images at a flying hei...