![Comparison of relative ([2010-200]/2000) built and population change at the district level. The relative population change results are adopted from Stow et al. (2016).](https://www.researchgate.net/profile/John-Weeks-6/publication/327271778/figure/tbl2/AS:938709117587458@1600817102896/Comparison-of-relative-2010-200-2000-built-and-population-change-at-the-district_Q320.jpg)
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Patterns of land cover and land use change within the two major metropolitan areas of Ghana
Geocarto International
Abstract and Figures
Sub-Saharan Africa is among the world’s fastest urbanizing regions. However, there is a lack of reliable data to estimate the amount and rates of urban expansion on the African continent. The objective of this study is to improve our understanding of urbanization in sub-Saharan Africa. Remote sensing methods and spatial metrics are combined to compare the growth, built density, land use composition, and fragmentation of Accra and Kumasi, the two major cities of Ghana between 2000 and 2010. Results show that Accra and Kumasi grew at an annual rate of 4.5% and 6% respectively. Accra added the most non-residential built land, and growth in both cities was compact. Finally, the urban-rural interface located within a 2 km buffer beyond the urban core experienced the greatest amount of fragmentation between 2000 and 2010 for both cities.
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... Ecosystems in Ghana are also not unaffected by the effects of degradation, which is increasingly drawing the attention of researchers and policymakers. Under pressure from population growth from 5 million during independence in 1957 to 31 million in 2020 (Toure et al., 2020), climate change and other drivers such as wildfires (Dahan et al., 2023), which according to FAO (2022), Davey and Sarre (2020) contribute significantly to LULC degradation, Ghana's forest heritage is shrinking (Ben-Michael et al., 2022;Koranteng et al., 2019;Shoyama et al., 2018). Big changes in LULC have occurred in tandem with population increase, particularly in Accra, Kumasi (Forest-savannah mosaic zone), Tamale (Guinea-savannah zone), and Sekondi-Takoradi (Acheampong et al., 2018;Addae & Oppelt, 2019;Braimoh, 2004). ...
... Although studies have been carried out to assess LULCs and the degradation factors that cause them, few have made a comparative analysis of homologous and vulnerable ecological zones with analyses of the rate of degradation of LULCs. Of note are the LULC studies conducted at the city/municipal level in Ghana mostly capture LULC change patterns, the drivers and impacts and implications in different locations across the country including Accra and Kumasi metropolitan areas (Addae & Oppelt, 2019;Toure et al., 2020), Sekondi-Takoradi metro area (Acheampong et al., 2018;Aduah & Baffoe, 2013), New Juaben (Attua & Fisher, 2011) and Kintampo North Municipality (Bessah et al., 2019) Some of the city/municipal level studies compared the patterns of urban development between cities in the northern and southern parts of Ghana (Adjei et al., 2014). ...
Ghana is increasingly affected by climate change, increased soil aridity, demographic problems, and unfavourable environmental factors. In the context of conservation, protection and sustainable management, this study assessed the loss, gain and stable areas of vegetation cover in Ghana by considering four districts namely West Gonja and West Mamprusi; Sene and Afram Plains in two major ecological zones respectively (Guinea-savannah and Forest-savannah mosaic) to make a comparative study of their level and intensity of degradation. For this purpose, remote sensing (IMPACT toolbox), GIS and quantitative analysis (PontiusMatrix42) approaches were used and applied on Landsat ETM+, OLI TIRS and Sentinel 2B images (2001, 2011, 2021). The result shows that land uses land covers (LULCs) are changing with a high level of dynamism in both ecological zones, with particular mention over the last decade (2011–2021) in terms of degradation in the Guinean savannah zone. Losses in both zones are more considerable than gains and stability. Each zone is marked more by changes in quantity than exchanges and shifts in LULCs, thus giving us information on the rate of loss of forest resources. It is therefore essential to put in place adequate measures to fight this irreversible loss if no action is taken.
... The phenomenon of land use/land cover (LULC) change is one of the significant indicators of such impacts (Umukiza et al. 2021). Alterations in LULC are a significant topic of global discourse due to being recognized as a primary contributor to worldwide environmental transformations (Toure et al. 2020). LULC changes have been identified as the main driving force of global change (Nyatuame et al. 2023) and have essential impacts on hydrological processes, the economy, and the ecology of watersheds (Marie Mireille et al. 2019). ...
Landuse alteration is a critical factor that exerts influence over hydrological mechanisms and the oversight of water resources across the globe. Northern Ghana is characterized by erratic rainfall, leading to the intense construction of small dams and dugouts. This study investigated historical landuse/cover (LULC) changes and physical factors associated with surface runoff generation within eight (8) sub-catchments namely; Guno, Gbahali, Sambu, Duago, Denugo, Kwisini, Sandu, and Nyeko, with areas of 29.5, 110, 38.5, 106.04, 67.81, 2.59, 10.56 and 120.65 km², respectively, located in four (4) regions of northern Ghana. For LULC change detection, historical satellite imagery and geospatial data were used with the aid of remote sensing and applying supervised maximum likelihood classification to Landsat images of 1995, 2005, 2015, and 2023. Runoff factors and depths were identified based on LULC classes, hydrologic soil groups, and precipitation conditions prevailing in the areas, based on the curve number (CN) method. With regards to LULC, the results from the overall analysis gave an insight into the rampant conversion, where grassland/mix vegetation witnessed significant declines, with decreases ranging from 150 to 395.25% in different catchments. Agricultural and arable lands emerged as the dominant landuse category, indicating a remarkable expansion of 11.61–51.17 km², from 1995 to 2023 respectively, followed by built-up areas. While grassland decreased in all catchments over the same period, in some places, open tree (savannah woodland) increased, which confirmed the implementation of the afforestation policy. The CN values offered essential insights into the hydrological characteristics of each catchment. In addition to the impact of LULC and watershed characteristics on runoff, the observed variations in runoff patterns can be attributed to interannual variability in total annual precipitation which is critical driver of runoff. The findings hold significant importance for developing effective strategies and integrated watershed management policies to contribute to better water resource management and inform sustainable landuse planning in the face of changing environmental conditions.
... The ALC is also described as the use of arable property for non-agricultural uses, such as residential, industrial, and commercial ones during the economic growth process (Azadi et al., 2011(Azadi et al., , 2016Rondhi et al., 2018;Teshome, 2014;Ustaoglu & Williams, 2017). Such LUC process has widely occurred in the current economic development and increase in population (Hu et al., 2019;Peerzado et al., 2018;Toure et al., 2018). Currently, crop production occupies about 11% (about 1.4 thousand million hectares) of the global surface area (about 13 thousand million ha), including arable land and territory under permanent crops. ...
This study aimed at investigating the harm from ecosystem services (ESs) according to agricultural land conversion (ALC) by using meta-analysis. The results of meta-regression showed that spatiotemporal effects had significant influences on some ES losses, and the maximum spatial impacts were relevant to Asia and Europe. Moreover, the results of ALC rate coefficients in meta-regression indicated that three large losses of ES were related to soil erosion (0.314), air pollution (0.202), and climate change (0.161). Therefore, the ALC should be done at a suitable conversion rate to reduce ES losses. Accordingly, administrators are suggested to consider careful research planning for the ALC in the process of economic development. Other strategies highlighted the importance of ALC–ES interactions for human well-being, such as measuring the pricing of goods and services based on land resources, continuously monitoring illegal ALC, and imposing taxes on unplanned ALC.
... The definition of ALC also refers to the conversion of dry or barren land in accordance with the laws of most states (Azadi et al., 2011;Azadi et al., 2015;Rondhi et al., 2018;Teshome, 2014;Ustaoglu and Williams, 2017). Therefore, the process of LUC has widely occurred in the current economic development and population growth (Hu et al., 2019;Peerzado et al., 2018;Toure et al., 2018). The ALC, which is the most common kind of LUC, may result in difficulties like agricultural land loss and food shortages (Loehr, 2012;Zhong et al., 2020). ...
Land use change (LUC) is one of the main factors of economic development, and humans have been changing land use for many years. Agricultural land conversion (ALC) is determined as a major process in many developing countries. The aim of this study was to investigate the widespread ALC and its main socio-economic impacts in developing countries during the last 50 years. This study was conducted through a meta-analysis of 56 original articles that identified the main impacts of the ALC from the 19th century onwards in four continents, including Africa, Asia, Europe, and America. The findings of meta-regression showed that spatiotemporal impacts had significant influences on socio-economic impacts, and the most important spatial impacts were related to the continents of America and Asia. In addition, the results of ALC’s rate coefficients in meta-regression indicated that the greatest social impacts were related to crime (2.17%) and the greatest economic impacts were related to endangering households’ revenue (2.98%). Therefore, it is concluded that the rapid conversion of agricultural land to achieve economic development leads to socio-economic impacts, and such economic development cannot be sustainable. Accordingly, it is suggested that the ALC consider such things as planning detailed investigations for the ALC, assessing the value of goods and services provided by agricultural land, monitoring unauthorized ALCs, and imposing fines and taxes on the unplanned ALC. Agricultural land provides important non-market goods and services with good management. Improper conversion of agricultural land to non-agricultural land makes it unproductive and endangered, leading to global warming and climate change.
... Early studies conducted in Kumasi Metropolitan Assembly (KMA) attempted to quantify and spatially (Nero et al., 2017;Abass et al., 2018;Engelhardt, 2012) present the distribution of UGS above and beneath the ground carbon pools, determine the extent of urban heat, effects of green roofs on thermal discomfort in indoor spaces, and the perception of the populace in relation to their immediate settings and prevailing microclimatic conditions (Koranteng et al., 2021). Studies conducted by Campion (2012) and Mensah et al. (2020) primarily delved into issues related to the sustenance of UGS, land use systems (Toure et al., 2020), urbanisation, extreme events and wetlands. Twumasi et al. (2021) compared land surface temperature and lushness density of two major cities in Ghana. ...
This study investigates the spatial variability of some remote sensing indices representing built-up areas, vegetation , bareness, and urban heat island (UHI), based on time-series Landsat TM/ETM+ and OLI/TIRS datasets archived for 1980-2020 period from the US Geological Survey's website for Kumasi Metropolitan Area in Ghana. Modules for Land Use Change Evaluation (MOLUSCE) and Cellular Automata Artificial Neural Network (CA-ANN) algorithms and simulations in QGIS were used to predict future changes (2020-2050) for land-use systems in Kumasi. Findings revealed urbanization/built-up areas (+108.02%) contributed massively to the decline of forest areas (− 93.34%) and farmlands/shrubs (− 31.53%), thereby making Kumasi lose its once critical green position as the "Garden City of West Africa." UHI moderately and strongly correlated positively against built-up (R 2 =0.78, p < 0.0001) and bareness (R 2 =0.96, p < 0.0001) indices, respectively. By contrast, UHI showed a statistically significant inverse relationship with the vegetative index (R 2 =0.97, p < 0.0001). Future land-use scenarios revealed more forests, waterbodies, and farmlands/shrubs will be lost, influencing urban temperature and water supply. The multipurpose advantages of urban green space are ingrained in the grand urban model. Contextually, the Metropolis's resilience has been hampered by inconsistency in the performance of institutional roles, competition for land ownership rights over green areas, and little investments or prioritization of green spaces. An integrated collaborative governance framework is proposed to unify actions, address power crisis and factors that influence governance of green infrastructure, UHI and land cover change.
... Two approaches were used to assess population growth in this study. First urban density (Equation (6)) also referred to urban land density in other literatures (Toure et al. 2020); and second, the annual change rate (Equation (7)) which is more reliable for comparison studies of more than one area with different area sizes . ...
With rapid urban expansion across Tanzania, there is a need to institute steps to address factors and forms as well as impacts and challenges associated with the observed trend. This study’s aim is to use spatial urban landscape indices to analyze the spatial changes in urban forms, patterns, and rates across 11 urban centers in Tanzania over a 30-year study period (1990–2020). During the past three decades, urban lands of 11 cities and town in Tanzania have grown by a total of 480 km². Leapfrog growth was found as the most dominant form of urban expansion in Tanzania while Dodoma, the capital city of Tanzania, had the highest rate of urban expansion when compared to all other individual cities. The most robust and significant interaction of the AWMLEI and MLEI was found in Kigoma, Arusha, Mtwara, Mafinga, and Tunduma cities. In contrast, Mbeya agricultural city, Arusha the tourist city, Tabora, and Geita Lake zone areas did show their own peculiarities revealing an interesting spatial temporal variation in rate and form of expansion. The outcome of this study reveals that the influence and management of economic and socio-cultural opportunities will be an effective tool for the determination of the rapidly expanding cities and towns of Tanzania.
... Then, the LULC changes near urban areas will increase the potential for carbon emissions. Meanwhile, based on a previous study, forest and agricultural land changes dominate the discussion near urban areas (Mena et al., 2017;Sejati et al., 2018;Toure et al., 2020). Forest cover is LULC class with 14 tons/ ha high carbon storage, while urban areas have no carbon storage (Agus et al., 2013). ...
This study explores the relationship between carbon emission patterns and the land surface temperature (LST) changes due to the rapid urbanization in the Semarang Metropolitan Region (SMR), an Indonesian area that has experienced rapid urban growth compared to other urban areas. This research used the stock-difference and gain–loss methods to calculate carbon stocks and emissions. Then, band 6 on Landsat 5 TM (2008) and band 10 on Landsat 8 OLI (2013 and 2018) were used to calculate the LST changes. These results showed that the peri-urban area had a more significant change. The correlation between carbon emissions and an increased SMR temperature correlates to 0.646. This shows that the carbon emissions pattern promotes temperature dynamics in the SMR. Furthermore, this study proved the release of carbon emissions in line with LST dynamics spatially. In this case, this study proved that rapid urbanization in the SMR promotes both carbon emission and LST. Those changes are also affected by vegetation canopy availability and other activities. As a result, the government must prioritize spatial planning in the SMR to mitigate environmental change risk. In addition, the government must develop novel strategies to deal with a wide range of fast and unpredictable potential changes in the urban area and its surroundings.
... At present, China is engaged in an important period of building a new pattern of urban-rural economic and social integration [1][2][3]. Facing the strategic goals of industrialization [4], urbanization, and new rural construction, in view of the imbalance of urban and rural land use structures [5,6], a large number of rural land waste [7,8], and destruction of cultivated land resources [9] and so on, the country puts forward the rural settlements consolidation [10] and the link between increase and decrease of urban and rural construction land [11,12] strategies, which do not simply reduce expenditures but also free up resources for other projects. ...
Taking the supplement of the quantity and quality of cultivated land in rural settlements as the departure point, this paper discusses the spatial and temporal integration reconstruction method of rural settlements. The disorderly expansion of residential areas in Pinggu District, Beijing, China has led to the erosion of high-quality cultivated land in the region and the advantages of mountain resources have not been fully utilized in this area. Therefore, Pinggu District was selected as the research area. Using the spatial analysis function in GIS, this paper uses the comprehensive correction method of the per capita construction land standard and the neighborhood substitution method to analyze the quantitative potential of rural settlements to supplement cultivated land and the qualitative grade of cultivated land after arrangement. A combination of exclusion matrices are employed to identify the spatial and temporal arrangements of rural settlements. The research shows that the effective cultivated land area of rural settlements in Pinggu District is 514.24 ha, and the coefficient of increasing cultivated land is 9.25%. Rural residential areas in the district are divided into priority sorting area, key sorting area, moderate sorting area, and restricted sorting area; they account for 18.13%, 21.10%, 20.85%, and 39.93% of the total area, respectively. According to the regional characteristics and dominant factor of the different consolidation areas, corresponding consolidation goals, models, and engineering measures are proposed to enrich the theory and approach to village planning and to provide a reference for practitioners engaged in regional rural land consolidation. The innovation of this study is putting forward the consolidation objectives, models and engineering measures based on the regional characteristics and leading factors of different land consolidation areas. This study has reference significance for the formulation and implementation of regional rural settlements consolidation planning and the policy of increasing and decreasing urban and rural construction land.
... Changes in LULC is significant to meet the current demand of human needs like land, water and vegetation (Powers et al., 2019;Nath et al., 2018;Toure et al., 2020). Anthropogenic activities, i.e., deforestation, urbanization, agriculture build-up, and further land degradation, are responsible for these changes (Noszczyk, 2019). ...
In the sustainable management of natural resources, land use and land cover (LULC) changes play an essential role. Pakistan is rich in biodiversity and provides ecosystem services to the country’s population, especially the mountains of the northern highland. These areas have experienced extensive depletion of ecosystem services and are susceptible to fast LULC changes. Real-time monitoring and assessment based on spatio-temporal are important to know such LULC changes. This study examines LULC in the northern mountains of Pakistan from MODIS (MCD12Q1) time series from 2001 to 2018. LULC was classified into ten significant classes. Findings of the data revealed that shrublands (0.33-0.17%), grasslands (45.83-41.74), and cropland (12.71-10.47) were decreased significantly. At the same time, savannas, permanent wetlands, urban and built-up lands, natural vegetation, permanent snow and ice, and barren lands increased substantially over the entire period. Due to the lack of baseline data, the LULC map will play an essential role in the sustainable management of LULC in the Hindu Kush, Karakoram and Himalayan regions of Pakistan. For the sustainable maintenance of the mountainous ecosystem, comprehensive research is recommended about these LULC vulnerabilities locally and regionally.
... The use of alternative analytical method(s) can also be considered as potential extension as observed in a related study of Jin et al. (2018) where 110 cities within the Yangtze River Economic Belt (YREB) were analyzed with the stochastic frontier analysis (SFA) and the use of the local indicators of spatial association (LISA) statistic. (Toure et al., 2020). ...
A systematic understanding of the dynamics of land consumption is extremely important for human well-being and especially vital for the ecological balance of the sub-Saharan Africa (SSA) region. Remarkable land use/land cover changes due to climate change, urbanization, and food demand have affected the spatio-temporal dynamics of built-up land footprints (BLFs) in SSA. By using spatial econometric techniques, this study investigates the spatio-temporal evolution and key drivers of built-up land footprints in 28 SSA countries from 2000 to 2017. Our results show how an appropriate consideration of the role of spatial effects can shed new insights into the convergence process of built-up land footprints. Foremost, the study reveals significant evidence of both absolute and conditional convergence in BLFs over the experimental period. Additionally, the estimation indicates that bio-capacity plays an important role in cutting built-up land footprints in SSA countries as there was a faster conditional convergence in countries with higher biocapacity. Moreover, the study outlined that the promotion of globalization and urbanization draws more pressure on the built-up environment and makes it challenging to reduce BLFs in SSA. In addition, this study found evidence for an inverted U-shaped nexus between per capita built-up land footprints and per capita gross domestic product (GDP), supporting the prediction of the environmental Kuznets curve (EKC) hypothesis.
Currently, half of the world's population lives in urban areas and the tempo of urbanization is expected to continue unabated during the 21st century, with most of the growth occurring in the developing world. The metropolitanization of African urban centres has brought in its wake several challenges, including uncontrolled physical development, inadequate and deteriorating infrastructure, and traffic congestion. To address the challenges, there is the need to understand the patterns of growth and structure of these urban centres. However, little work has been done in this regard. In this paper, we sought to model the patterns of growth of the Greater Kumasi Metropolitan Area (GKMA) in Ghana. Using GIS and multiple-regression techniques, we have demonstrated that the form and growth of GKMA follow discernible patterns that can be explained by the monocentric city model and the ribbon development pattern of spatial growth. There are non-linear, negative relationships between distance from Central Kumasi and distance from highways (as predictors) and the dependent variables population density and population growth. The findings indicate that Africa's metropolitan areas follow discernible patterns that can be explained by existing models applied in other regions.
Urbanization in Africa (and the wider developing world for that matter) has often been misunderstood by Western observers on the lookout for Western‐style cities and suburbs. In these parts of the world, rapid urbanization has led to continuing changes in the form and shape of cities, as peri‐urban zones shift swiftly from rural to urban. While some descriptions of the peri‐urban zone suggest an amorphous area filled with low‐income residents, others argue that the zone is highly diverse. Using population census data, spatial modeling and regression analysis, we show that urban expansion at the edge of the city of Accra, Ghana, is not amorphous and does indeed show some discernible patterns. These patterns are represented by four hypotheses tested in this study — the spreading pancake, development node, village magnet and ribbon hypotheses. While the assumption that urban growth occurs in concentric rings around a central city (represented by the spreading pancake model) holds for Accra, this pattern of growth combines with other patterns to create a still‐evolving urban form in the city's peri‐urban zone. These include clustering of growth around a port city, a number of old villages and along improved highways radiating from the city.
Résumé
En Afrique (et dans le monde en développement en général), l'urbanisation a souvent été mal comprise par les observateurs occidentaux en quête de villes et banlieues de type occidental. Dans ces parties du monde, l'urbanisation accélérée a entraîné des modifications constantes dans la conformation des grandes villes, les terrains ruraux périphériques devenant rapidement des zones urbaines. Selon certaines descriptions, la périphérie est amorphe, envahie d'habitants à faible revenu; selon d'autres, elle est empreinte d'une grande diversité. À l'aide de données de recensement, d'une modélisation spatiale et d'une régression statistique, on peut montrer que l'expansion urbaine aux limites de la ville d'Accra au Ghana n'est pas amorphe et qu'elle présente des schémas tout à fait identifiables. Ceux‐ci correspondent aux quatre hypothèses évaluées dans cette étude: la crêpe étalée, le pôle de développement, les villages aimantés, le ruban. L'idée que la croissance urbaine se diffuse en cercles concentriques autour d'une ville centrale (modèle de la crêpe étalée) s'applique à Accra, mais ce modèle est associéà d'autres schémas pour créer une forme urbaine en évolution permanente dans sa périphérie. On trouve ainsi une concentration de croissance autour d'une ville portuaire, de plusieurs villages pré‐existants, ainsi que le long de grandes routes rénovées qui rayonnent à partir de la ville.
The increasing availability of high resolution imagery has triggered the need for automated image analysis techniques, with reduced human intervention and reproducible analysis procedures. The knowledge gained in the past might be of use to achieving this goal, if systematically organized into libraries which would guide the image analysis procedure. In this study we aimed at evaluating the variability of digital classifications carried out by three experts who were all assigned the same interpretation task. Besides the three classifications performed by independent operators, we developed an additional rule-based classification that relied on the image classifications best practices found in the literature, and used it as a surrogate for libraries of object characteristics. The results showed statistically significant differences among all operators who classified the same reference imagery. The classifications carried out by the experts achieved satisfactory results when transferred to another area for extracting the same classes of interest, without modification of the developed rules.
There is a widespread concern about urban sprawl. It has negative impacts on natural resources, economic health, and community character. Without a universal definition of urban sprawl, its quantification and modeling is difficult. Traditionally, urban sprawl was described using qualitative terms, and landscape patterns. Quantitative methods are required to help local, regional and state land use planners to better identify, understand and address it. In this study, an integrated approach of remote sensing and GIS was used to identify three urban growth types of infilling growth, outlying growth and edge-expansion growth at the city of Guangzhou, China. Spatial metrics were used to characterize long-term trends and patterns of urban growth. Result shows that the proposed method can identify and visualize different urban growth types. Infilling growth is the dominant expansion type. Edge-expansion is concentrated at suburban areas. Outlying growth mainly occurs relatively far from the urban core. The analysis shows that initially the urban area expands mainly as outlying growth, causing increased fragmentation and dispersion of urban areas. Next, growth filled in vacant non-urban area inwards, resulting into a more compact and aggregated urban pattern. The study shows an improved understanding of urban growth, and helps to provide an effective way for urban planning.
In Sub-Saharan Africa rapid urban growth combined with rising poverty is creating diverse urban environments, the nature of which are not adequately captured by a simple urban-rural dichotomy. This paper proposes an alternative classification scheme for urban mapping based on a gradient approach for the southern portion of the West African country of Ghana. Landsat Enhanced Thematic Mapper Plus (ETM +) and European Remote Sensing Satellite-2 (ERS-2) synthetic aperture radar (SAR) imagery are used to generate a pattern based definition of the urban context. Spectral mixture analysis (SMA) is used to classify a Landsat scene into Built, Vegetation and Other land covers. Landscape metrics are estimated for Built and Vegetation land covers for a 450 m uniform grid covering the study area. A measure of texture is extracted from the SAR imagery and classified as Built/Non-built. SMA based measures of Built and Vegetation fragmentation are combined with SAR texture based Built/Non-built maps through a decision tree classifier to generate a nine class urban context map capturing the transition from unsettled land at one end of the gradient to the compact urban core at the other end. Training and testing of the decision tree classifier was done using very high spatial resolution reference imagery from Google Earth. An overall classification agreement of 77% was determined for the nine-class urban context map, with user's accuracy (commission errors) being lower than producer's accuracy (omission errors). Nine urban contexts were classified and then compared with data from the 2000 Census of Ghana. Results suggest that the urban classes appropriately differentiate areas along the urban gradient.
We analyze amounts and spatial patterns of land cover and land use change (LCLUC) and particularly change to Built for four contiguous regions of southern Ghana between 2000 and 2010. Our objective is to understand the degree of urban expansion relative to urban densification during this time frame, to understand the relationship between population growth and LCLUC at the census district level, and to explain the patterns of New Built LCLUC throughout this study area. During the study period 1.5% of the study area transitioned to Built, an increase of 56% Built area since 2000, while population increased by 33%. Most (84% of total study area) of this change to Built involved conversion from Agricultural land use and occurred predominantly in suburban and periurban areas zones of the Accra and Kumasi metropolitan areas. While total population and amount of Built LCLU variables co-vary strongly at the census district level at the beginning and end of the study period, change in population and Built are less strongly correlated. In fact, we observe that new Built development increased at a greater rate than population growth within peri-urban areas of Accra and Kumasi, frequently occurring as spaced residential land use composed of large houses with minimal urban infrastructure.
Rates of population growth and urbanization currently taking place in sub-Saharan Africa are and will be the highest in the world, providing impetus for remote-sensing-based monitoring of land cover and land use change (LCLUC). The objective of this study is to assess the utility of using segmentation and classification information derived from an object-based classification of an image at a later date (t = 2) to aid in the segmentation and classification of an image at an earlier date (t = 1) for the same area, in the context of a post-classification comparison for LCLUC analysis within Kumasi, Ghana. This object-based temporal inversion approach was found to increase the accuracy of the t = 1 classification and land use change classifications by 6.2% and 6.6%, respectively, compared to a traditional, non-constrained object-based image analysis (OBIA) approach.
In many parts of the developing world, it has been observed that growing population pressure and the development of market economies as a cause and consequence of urbanisation are leading to significant changes in land tenure practices and related rights. Increasingly, land rights in urban and peri-urban areas are becoming more individualised and privatised, in contrast to communal or usufruct rights. Using questionnaire surveys and focus group discussions, this article explores migrants' and indigenes' access to peri-urban land in Ghana's largest metropolis, Accra. The study found that an increase in land transactions due to the emergence of land markets in this land-scarce area of Ghana is resulting in usufruct and inheritance rights over land under customary tenure regimes no longer being guaranteed, as many people belonging to land-owing families (indigenes) in peri-urban Accra are left to compete for less land with migrants or strangers. The implications of this situation for urban development in Ghana are explored.
The Normalized Difference Water Index (NDWI) is a new method that has been developed to delineate open water features and enhance their presence in remotely-sensed digital imagery. The NDWI makes use of reflected near-infrared radiation and visible green light to enhance the presence of such features while eliminating the presence of soil and terrestrial vegetation features. It is suggested that the NDWI may also provide researchers with turbidity estimations of water bodies using remotely-sensed digital data.