1,785 research outputs found

    Urban sprawl in the state of Missouri : current trends, driving forces, and predicted growth on Missouri's natural landscape

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    Title from PDF of title page (University of Missouri--Columbia, viewed on March 5, 2013).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Hong S. HeIncludes bibliographical references.Vita.Ph.D. University of Missouri--Columbia 2012."December 2012"Missouri reflects a full range of sprawl characteristics that include large metropolitan centers, which led growth in 1980s, and smaller metropolitan and rural areas, which led growth in 1990s. In order to study the historical patterns of sprawl, there is a need to quantitatively and geographically depict the extent and density of impervious surface for three time periods of 1980, 1990, and 2000 for the entire state of Missouri. Mapped impervious surface is the best candidate of ancillary data for dasymetric mapping of population in several comparison studies. The current research examines the performances of dasymetric mapping of population with imperviousness as ancillary data and regression analysis of population using imperviousness as a predictor Results from this work can be aggregated to any geographical unit (hydrologic boundaries, administrative boundaries, etc.). A pilot future urban growth study for the two decades of 1980s and 1990s was done in Missouri. The historical urban growth of the two decades were analyzed then coupled with various predictor variables to investigate the influence of each predictor variables towards the process of urban growth. The knowledge learned from the process is then used to build an urban growth simulation model that is GIS-based with open framework for ease of management and improvement. Pixel level urban growth was simulated for year 2010, 2020 and 2030. This model framework is developed with the ultimate goal of simulating urban growth for the entire state of Missouri.Includes bibliographical reference

    Metropolitan Spatial Structure: Measuring the Change

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    Since 1990s the metropolitan spatial structure has been alleged to be growing smarter. Excessive suburbanization trends characterizing urban form since the Second World War are now believed to be reversing in favor of urban environment. The reversal is driven by changing household preferences as well as a series of changes that urban areas have gone through which make them more attractive living environments for some demographic groups. This is a dissertation consisting of three related essays which examine change in the metropolitan spatial structure over the past two decades to determine if suggested changes are in fact observable in urban form. In measuring change, I consider a number of measures that characterize urban form, particularly density, concentration, clustering, infill and growth allocation of urban growth. Given the prevalence of foreclosure crisis in the later part of the first millennium decade, I also explore the impact of urban form on accumulation of foreclosures as an indicator of future spatial structure change. The study finds two different trends at force facing the American metropolitan spatial structure. For the metropolitan areas with weak growth pressures or those loosing population since 1990, suburbanization trends continue to define spatial structure. However, in the metropolitan areas that are facing moderate and strong population growth pressures and constituting the majority of the largest urban areas in the U.S., the importance of urban center is ever more significant and their spatial structure is greatly dependent on denser urban form. Desirability for urban environment also manifested itself in the spatial distribution of foreclosures in Maryland

    Forecasting Vacancy Dynamics in Growing Versus Shrinking Cities: A Smart City Initiative

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    Every city seeks to spur economic development, and land, especially vacant land, plays an important role in these endeavors. Although vacant land exists in every city regardless of whether they are growing or shrinking, the causes and effects of changes in vacant land differ. While large scale annexation can increase vacant land in growing cities, depopulation and economic downturn may increase vacant properties in shrinking cities. However, despite these different characteristics, most cities pursue growth-oriented development strategies due, partially, to their inability to accurately predict future urban growth/decline patterns. Therefore, understanding land use alternation patterns and predicting future possible scenarios is critical when developing more proactive land use policies on urban decline and regeneration. In this study, the city of Chicago, Illinois, was used as a case site to test an urban land use change model predicting future vacant lands in shrinking cities, and the city of Fort Worth, Texas, was selected to forecast vacant land transformation in growing cities. By understanding not only simple decrease or increase of vacant properties but also analyzing historical patterns of vacancy changes and predicting the probability of future transitions with accuracy outputs, this research can be used to improve policies on vacancy. This project employed the Land Transformation Model (LTM) which combines GIS and artificial neural networks to forecast land use change. While this research used causal drivers to predict future vacant land changes in growing and shrinking cities, findings can also be used to simulate land use changes to suggest suitable alternatives for shrinking and growing cities with high risk of vacancy and future infill development plans. Study results indicate that housing market conditions and economic factors are the primary variables contributing to land vacancy decline with mobility and physical conditions being stronger predictors of vacant land specifically in growing cities. In terms of plan quality associated with vacancy-related policies, this study found that Fort Worth is more attentive to socially and physically vulnerable areas, working to revitalize the economy and reduce vacant properties, than healthier communities while Chicago may need to improve their policies regarding the transportation accessibility and physical conditions of their structures

    Exploring zoning scenario impacts upon urban growth simulations using a dynamic spatial model

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    Dynamic spatial models are being increasingly used to explore urban changes and evaluate the social and environmental consequences of urban growth. However, inadequate representation of spatial complexity, regional differentiation, and growth management policies can result in urban models with a high overall prediction accuracy but low pixel-matching precision. Correspondingly, improving urban growth prediction accuracy and reliability has become an important area of research in geographic information science and applied urban studies. This work focuses on exploring the potential impacts of zoning on urban growth simulations. Although the coding of land-use types into distinct zones is an important growth management strategy, it has not been adequately addressed in urban modeling practices. In this study, we developed a number of zoning schemes and examined their impacts on urban growth predictions using a cellular automaton-based dynamic spatial model. Using the city of Jinan, a fast-growing large metropolis in China, as the study site, five zoning scenarios were designed: no zoning (S0), zoning based on land-use type (S1), zoning based on urbanized suitability (S2), zoning based on administrative division (S3), and zoning based on development planning subdivision (S4). Under these scenarios, growth was simulated and the respective prediction accuracies and projected patterns were evaluated against observed urban patterns derived from remote sensing. It was found that zoning can affect prediction accuracy and projected urbanized patterns, with the zoning scenarios taking spatial differentiation of planning policies into account (i.e., S2–4) generating better predictions of newly urbanized pixels, better representing urban clustered development, and boosting the level of spatial matching relative to zoning by land-use type (S1). The novelty of this work lies in its design of specific zoning scenarios based on spatial differentiation and growth management policies and in its insight into the impacts of various zoning scenarios on urban growth simulation. These findings indicate opportunities for the more accurate projection of urban pattern growth through the use of dynamic models with appropriately designed zoning scenarios. Keywords:urban growth simulation; zoning scenarios; cellular automaton models; spatial matching; prediction accurac

    Cityscape, poverty and crime: a quantitative assessment using VHR imagery

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    [EN] The first part of this work reviews the potential applications of satellite remote sensing to regional science research in urban settings. The availability of satellite remote sensing data has increased significantly in the last two decades. The increasing spatial resolution of commercial satellite imagery has influenced the emergence of new research and applications of regional science in urban settlements because it is now possible to identify individual objects of the urban fabric. The most common applications found in the literature are the detection of urban deprivation hot spots, quality of life index assessment, urban growth analysis, house value estimation, urban population estimation, urban social vulnerability assessment, and the variability of intra-urban crime rates. The satellite remote sensing imagery used in these applications has medium, high or very high spatial resolution (Landsat MSS, Landsat TM and ETM+, SPOT, ASTER, IRS, Ikonos and QuickBird). Consistent relationships between socio-economic variables derived from censuses and field surveys and proxy variables of vegetation coverage measured from satellite remote sensing data have been found in several cities in the US. Different approaches and techniques have been applied successfully around the world, but local research is always needed to account for the unique elements of each place. Spectral mixture analysis, object-oriented classifications and image texture measures are some of the techniques of image processing that have been implemented with good results. This work contributes empirical evidence about the usefulness of remote sensing imagery to quantify the degree of poverty at the intra-urban scale. This concept is based on two premises: first, that the physical appearance of an urban settlement is a reflection of the society; and second, that the people who reside in urban areas with similar physical housing conditions have similar social and demo- graphic characteristics. We evaluate the potential of the image-derived urban fabric descriptors to explain a measure of poverty known as the Slum Index. We found that these variables explain up to 59% of the variability in the Slum Index. Similar approaches could be used to lower the cost of socioeconomic surveys by developing an econometric model from a sample and applying that model to the rest of the city and to perform intercensal or intersurvey estimates of intra-urban Slum Index maps. The last part of this work analyzes the relation between the urban layout and crime. The link between place and crime is at the base of social ecology theories of crime that focus in the relationship of the characteristics of geographical areas and crime rates. The broken windows theory states that visible cues of physical and social disorder in a neighborhood can lead to an increase in more serious crime. Based on the premise that a settlement's appearance is a reflection of the society, we ask whether a neighbor- hood's design has a quantifiable imprint when seen from space using urban fabric descriptors computed from VHR imagery. The percentage of impervious surfaces other than clay roofs, the fraction of clay roofs to impervious surfaces, two structure descriptors related to the homogeneity of the urban layout, and the uniformity texture descriptor were all statistically significant. Areas with higher homicide rates tended to have higher local variation and less general homogeneity; that is, the urban layouts were more crowded and cluttered, with small dwellings with different roofing materials located in close proximity to one another, and these regions often lacked other homogeneous surfaces such as open green spaces, wide roads, or large facilities. These results seem to be in agreement with the broken windows theory and CPTED in the sense that more heterogeneous and disordered urban layouts are associated with higher homicide rates.[ES] La primera parte aporta una revisión de las aplicaciones de la teledetección satelital en la investigación de ciencia regional en entornos urbanos. La disponibilidad de imágenes satelitales se ha incrementado significativamente en las dos últimas décadas, al tiempo que la resolución espacial ha venido aumentando, lo que ha influenciado el surgimiento de investigaciones y aplicaciones de ciencia regional en zonas urbanas. Las aplicaciones más comunes son la detección de hot spots de pobreza urbana, la evaluación de índices de calidad de vida, el análisis del crecimiento urbano, la estimación de valores de vivienda, la estimación de población urbana, la evaluación de la vulnerabilidad social y las variaciones intra-urbanas en tasas de crimen. Las imágenes satelitales usadas tienen resolución espacial media, alta o muy alta (Landsat MSS, Landsat TM y ETM+, SPOT, ASTER, IRS, Ikonos y Quickbird). Se han encontrado relaciones consistentes entre variables socio-económicas obtenidas de censos y encuestas y variables de la cobertura de vegetación en varias ciudades de Estados Unidos. Algunas de las técnicas que se han implementado y obtenido buenos resultados son el análisis de mezcla espectral, las clasificaciones orientadas a objetos y las medidas de textura de la imagen. Se aporta evidencia empírica acerca de la utilidad de las imágenes satelitales para cuantificar el grado de pobreza a escala intra-urbana. Se basa en dos premisas: primero, que la apariencia física de un asentamiento urbano es un reflejo de la sociedad que lo habita; y segundo, que la población de áreas urbanas con condiciones físicas de vivienda parecidas tiene características sociales y demográficas similares. Evaluamos el potencial de los descriptores del tejido urbano extraídos de la imagen para explicar una medida de pobreza conocida como el índice Slum. Encontramos que esas variables explican hasta un 59% de la variabilidad en el índice Slum. Aproximaciones similares a esta podrían usarse para disminuir el costo de encuestas socioeconómicas por medio del desarrollo de un modelo econométrico usando una muestra y luego aplicando el modelo al resto de la ciudad, y para elaborar estimaciones inter-censales o inter-encuestas de mapas intra-urbanos del índice Slum. La última parte analiza la relación entre el trazado urbano y crimen. El enlace entre el lugar y el crimen está en la base de las teorías socio-ecológicas de crimen que se enfocan en la relación de las características de las áreas geográficas y las tasas de crimen. La teoría de las ventanas rotas afirma que las evidencias visibles de desorden físico y social en un barrio pueden llevar al incremento de crímenes más serios. Con base en la premisa de que la apariencia de un asentamiento es un reflejo de la sociedad, nos preguntamos si el diseño del barrio tiene un impacto cuantificable cuando se observa desde el espacio usando descriptores del tejido urbano obtenidos de imágenes de muy alta resolución. El porcentaje de superficies impermeables diferentes a los techos de arcilla, la fracción de techos de arcilla sobre las superficies impermeables, dos variables de estructura relacionadas con la homogeneidad del trazado urbano y la variable de textura uniformidad resultaron estadísticamente significativas. Las áreas con tasas de homicidio más altas tienden a tener mayor variación local y menor homogeneidad general; esto es, los trazados urbanos son más desordenados y hacinados, con pequeñas viviendas que tienen materiales diferentes en sus techos localizadas muy cerca unas de otras, y estas áreas carecen a menudo de otras superficies homogéneas tales como espacios verdes abiertos, vías amplias y grandes construcciones industriales o institucionales. Estos resultados parecen estar en acuerdo con la teoría de las ventanas rotas y CPTED en el sentido de que los trazados urbanos más desordenados y heterogéneos están asociados con tasas de homicid[CA] La primera part aporta una revisió de les potencials aplicacions de la teledetecció espacial a la investigació en ciència regional en entorns urbans. La disponibilitat de dades de percepció remota des de satèl·lits s'ha incrementat significativament a les dues últimes dècades. La resolució espacial de les imatges de satèl·lit comercials també han anat augmentant i això, ha influït en l'aparició de investigacions i aplicacions a la ciència regional en assentaments urbans. Les aplicacions més comunes trobades a la literatura són la detecció de punts calents de pobresa urbana, l'avaluació dels índex de qualitat de vida, les anàlisis de creixement urbà, l'avaluació de la vulnerabilitat social i les variacions intraurbanes de les taxes de crims. Les imatges de satèl·lit emprades tenen resolució espacial mitjana, alta o molt alta (Landsat MSS, Landsat TM i ETM+, SPOT, ASTER, IRS, Ikonos y Quickbird). S'han torbat relacions consistents entre variables socioeconòmiques obtingudes de censos i enquestes i variables de la cobertura de vegetació en varies ciutats del Estats Units. Algunes de les tècniques que s'han implementat i han donat bons resultats són l'anàlisi de mescla espectral, les classificacions orientades a objecte i les mesures de textura de les imatges. Es aporta evidència empírica sobre la utilitat de les imatges de satèl·lit per quantificar el grau de pobresa a escala intraurbana. Es bassa en dues premisses: primer, que l'aparença física d'un assentament urbà n'és un reflex de la societat que l'habita; i segon, que les persones que resideixen en àrees urbanes amb condicions físiques de vivenda paregudes tenen també característiques socials i demogràfiques similars. Avaluem el potencial dels descriptors del teixit urbà extrets de la imatge per explicar una mesura de pobresa coneguda com index Slum. Trobem que aquestes variables expliquen fins un 59% de la variabilitat de l'índex Slum. Aproximacions semblants a aquesta es podrien emprar per a disminuir el cost de les enquestes socioeconòmiques mitjançant el desenvolupament d'un model economètric utilitzant una mostra i després aplicant el model a la resta de la ciutat, i per elaborar estimacions inter-censals o inter-enquestes de mapes intraurbans de l'índex Slum. La darrera part analitza la relació entre el traçat urbà i el crim. L'enllaç entre el lloc i el crim està a la base de les teories socio-ecològiques del crim que es centren en la relació de les característiques de les àrees geogràfiques i les taxes de crims. La teoria de les finestres trencades afirma que les evidències visibles de desordre físic i social d'un barri pot portar a l'augment de crims més greus. Basant-se en la premissa de que l'aparença d'un assentament n'és el reflex de la societat, ens hi preguntem si el disseny del barri té un impacte quantificable quan s'observa des de el espai, utilitzant descriptors del teixit urbà obtinguts de imatges de molt alta resolució. Han resultat estadísticament significatius el percentatge de superfícies impermeables diferents a les teulades de argila, la fracció de teulades d'argila sobre les superfícies impermeables, dues variables d'estructura relacionades amb la homogeneïtat del traçat urbà i la variable de textura de uniformitat. Les àrees amb taxes d'homicidi més altes tendeixen a presentar una major variació local i una menor homogeneïtat general; és a dir, el traçats urbans són més desordenats i amuntonats, amb petites vivendes que tenen materials diferents a les seues teulades localitzades molt prop unes d'altres, i aquestes àrees manquen sovint d'altres superfícies homogènies, com ara espais verds oberts, vies amplies i grans construccions industrials o institucionals. Aquests resultats pareixen estar-hi d'acord amb la teoria de les finestres trencades i CPTED en el sentit de que els traçats urbans més desordenats i heterogenis estan associats amb taxes d'homicides mPatiño Quinchía, JE. (2015). Cityscape, poverty and crime: a quantitative assessment using VHR imagery [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59453TESI

    Environmental Influences on Past and Future Urban Development in the Arkansas-Red River Basin (USA), 1857-2050

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    Variability in physiography and land management can lead to differences in urban development rates and patterns in space and through time. While traditional studies have focused on contemporary anthropogenic impacts on the environment; relatively few have investigated and quantified the influence of biophysical forces, relative to human historical factors, on long-term and large-scale urban trends and patterns. In this research, I first developed a framework that uses readily available data to build fine-resolution historical land cover timelines over large areas. To build this timeline, I transformed pre-settlement land surveys (c.a. 1850s) and early aerial photographs (c.a. 1940s), and improved the mapping accuracy of the first national land cover dataset (GIRAS, 1975) to make it compatible with the contemporary national land cover database (1994-2006). Second, I used the compiled timeline to empirically analyze the historical development trends and rates around Little Rock city, Arkansas (USA). For this analysis, I developed a robust environmental-historical approach to emphasize the potential influences of environmental forces on shaping development transitions within and among-ecoregions. Finally, I studied the influence of physiography on historical and future (1975-2050) urban growth trends and patterns across an east-west gradient in the Arkansas-Red River basin. The products from this research have broad applications to urban planning, landscape ecology, an

    Urban green spaces enhance carbon sequestration and conserve biodiversity in cities of the Global South : case of Kumasi, Ghana

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    Urbanization has the propensity to alter ecosystems, enervate ecosystem function and possibly jeopardise human wellbeing. While adequate integration of nature into the city landscape can pragmatically ameliorate urban environmental challenges, particularly those related to climate change and ecosystem degradation, in the developing regions, especially in Africa, urban green spaces (UGS) are hardly planned for and their ecosystem services unquantified and hence misappropriated. This study analyses 1) the spatio-temporal dynamics and distributional equity, 2) carbon sequestration potential, and 3) biodiversity patterns of UGS in Kumasi metropolis, Ghana. Direct ecosystem assessment (inventory and survey) and remote sensing techniques were adopted in this study. The vegetation cover of Kumasi is about 33 % and is declining fourfold faster in recent years (2009 – 2014) than previously (986 – 2001). Per capita UGS area for 2009 and 2014 are significantly correlated with the socio-economic conditions of submetropolis. The green area stores about 3758.1 Gg C: equivalent to 270±22 t C/ha per UGS cover or 125.7 ± 8 t C/ha for the entire study area in both soil and vegetation. Exactly 176 tree species in 46 families of both native and exotic origins occur in the city. Carbon stocks and species richness differ significantly across UGS types. Natural forest, public parks, cemeteries and institutional compounds stored more carbon in vegetation whereas soil organic carbon storage was highest in the home gardens, farmlands, plantations, and grasslands. The outer fringes of the city support more species and carbon stocks than the core urban area. Species and trait diversity are important drivers of urban ecosystem productivity (carbon storage). UGS species richness correlated strongly with vegetation carbon storage in the city. UGS are carbon sinks and biodiversity reservoirs which can be relevant to climate change mitigation and adaptation as well as the overall wellbeing of urbanites. However, UGS cover is currently plummeting and is threatened by further urbanization processes including rise in population. Maintenance, expansion, and uniform distribution of green spaces in cities should be a priority for planners, national and local governments as well as traditional leaders. It is recommended that urban biodiversity and carbon stocks be integrated into national and regional biodiversity and carbon stock assessments in Africa.Durch Verstädterung besteht die Tendenz, dass Ökosysteme verändert werden, die Funktion von Ökosystemen geschwächt wird und möglicherweise das menschliche Wohlergehen gefährdet wird. Während eine angemessene Integration von Grünflächen in die Stadtlandschaft bei der Bewältigung der städtischen ökologischen Herausforderungen, besonders in Bezug auf Klimawandel und die Beeinträchtigung des Ökosystems, pragmatisch helfen kann, werden in Entwicklungsgebieten, vor allem in Afrika, kaum städtische Grünflächen (urban green spaces - UGS) geplant. Des Weiteren werden die von UGS geleisteten Ökosystemdienstleistungen zumeist nicht beziffert und demnach in globalen Analysen nicht erfasst. Diese Studie analysiert 1) die räumlich-zeitliche Dynamik und das Verteilungsmuster, 2) das Potential von Kohlenstoffbindung und 3) die biologische Vielfalt und Funktion von UGS im städtischen Großraum von Kumasi, Ghana. In dieser Studie wurden Methoden zur direkten Bewertung des Ökosystems und Fernerkundungstechniken verwandt. UGS in Kumasi umfassen z.Z. etwa 33 % des städtischen Großraum von Kumasi und diese Fläche schrumpfte in den letzten Jahren (2009 – 2014) viermal schneller als zuvor (1986 – 2001). Die pro Kopf Verteilung von UGS in Kumasi korreliert signifikant mit den dortigen sozioökonomischen Bedingungen. Die Grünflächen speichern etwa 3758,1 Gg Kohlenstoff; im Durchschnitt entspricht dies 270 ± 22 t Kohlenstoff / ha UGS oder 125,7 t Kohlenstoff / ha im gesamten Untersuchungsgebiet, sowohl in Form von Böden als auch Vegetation. Im Großraum Kumasi kommen 176 verschiedene Baumarten aus 46 heimischen und nicht-heimischen Familien vor. Kohlenstoffbestände und Artenvielfalt unterscheiden sich strak in Abhängigkeit des Typus von UGS. Reste natürlichen Waldbestandes, öffentliche Parks, Friedhöfe und Bäume auf dem Gelände von öffentlichen Institutionen speicherten mehr Kohlenstoff in der Vegetation, wobei der organische Kohlenstoffspeicher in privaten Gärten, auf Feldern, Plantagen und Grasflächen am höchsten war. Stadtrandgebiete haben eine höhere Biodiversität und speichern mehr Biomasse als der innenstädtische Bereich. Arten- und phenotypische Vielfalt haben einen grossen Einfluß auf die Funktion städtischer Ökosysteme. Das Ausmaß der Artenvielfalt in städtischen Grünflächen steht im engen Zusammenhang mit dem Kohlenstoffbestand in der städtischen Vegetation. Städtische Grünflächen sind wichtige Kohlenstoffspeicher und Quellen der biologischen Vielfalt, die für die Vermeidung von und Anpassung an Klimawandelfolgen und das allgemeine Wohlergehen von Städten sehr relevant sind. Allerdings gefährdet das rapide Bevölkerungswachstum und die zunehmende Urbaniserung die existierenden städtischem Grünflächen in Afrika. Instandhaltung, Erweiterung und auch eine verbesserte und gerechtere Verteilung von städtischen Grünflächen sollten für Städteplaner, Landesregierungen, Lokalverwaltungen und traditionelle Führer eine Priorität darstellen
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