This dissertation explores the symbolic structure of the metropolis, probing how neutral spaces may be imbued with meaning to become places, and tracing the processes through which the image of the city can come to be - and carry real consequences. The centrality of the image of the city to a broad array of urban research is established by injecting the question of image into two different research areas: crime and real estate in Washington, DC and the spatial structure of grassroots visual art production in Boston, Massachusetts. By pursuing such widely diverging areas of research, I seek to show the essential linkage between art and crime as they related to the image of the city and general urban processes of definition, distinction, and change. And yet, the research pursued here offers a mixed appraisal of strategies that pin urban prospects to image and image manipulation, from the great crime decline of the past two decades to the rise of the creative economy and application of urban branding campaigns. Across the analyses, I highlight tension between expectations of change and the essentially conservative forces of image. Far from rebranding the city, culture is shown to play a key role in locking in inequalities, undermining revitalization efforts, and generally explaining the reproduction and persistence of place over time, following the logic of the "looking glass neighborhood." Thus, culture is not nearly the tool to revalorize, relabel, and transform place so well depicted in studies nor do the buzz of cultural events shape markets and communities as effectively in "offcenter" cities. Place is not fixed for good, and can be "re-accomplished," albeit through decades-long demographic, cultural, and political processes. / Sociology

The quantification and prediction of soil properties is fundamental to further understanding the Critical Zone (CZ). In this study we aim to quantify and predict soil properties within a forested catchment, Marshall Gulch, AZ. Input layers of soil depth (modeled), slope, Saga wetness index, remotely sensed normalized difference vegetation index (NDVI) and national agriculture imagery program (NAIP) bands 3/2 were determined to account for 95% of landscape variance and used as model predictors. Target variables including soil depth (cm), carbon (kg/m²), clay (%), Na flux (kg/m²), pH, and strain are predicted using multivariate linear step-wise regression models. Our results show strong correlations of soil properties with the drainage systems in the MG catchment. We observe deeper soils, higher clay content, higher carbon content, and more Na loss within the drainages of the catchment in contrast to the adjacent slopes and ridgelines.

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The Homol'ovi region of northeastern Arizona was home to a dense prehistoric population with strong, archaeologically-visible ties to the Hopi Mesas. As an ancestral Hopi residential area, this region is an important part of the Hopi cultural landscape utilized contemporarily by Hopi people for religious and resource procurement purposes. However, while previous research indicates that the Cottonwood Wash drainage formed an important component of the Homol'ovi landscape, the archaeology of the wash and its adjacent uplands is poorly understood. This research adopts a two-pronged approach to assessing the efficacy of GIS analysis for interpreting the spatial distribution of archaeological sites within the Homol'ovi landscape. The deductive approach draws on principles of cultural landscape theory to construct a descriptive model of dimensions of Hopi land use on the basis of ethnographic documentation and Hopi traditional history. This model is applied to a database composed of survey data collected from the Cottonwood Wash vicinity and data from the Homol'ovi Research Program's survey of Homolovi State Park. The model is then operationalized through GIS analysis of site distributions, and the efficacy of the model for predicting the location of different types of prehistoric land use is evaluated. The second, inductive, approach examines site distribution relative to patterns of visibility and movement in the Homol'ovi region and identifies areas for the refinement of spatial data associated with shrines and petroglyphs in the region. On the basis of this two-pronged approach, a research strategy iteratively incorporating deductive and inductive analyses, coupled with the use of participatory approaches, is recommended for future research.

In recent decades, transmission of Trypanosoma cruzi, the causative agent of Chagas disease, by Triatoma infestans and other vector insects has expanded from historically rural areas to urban centers across Latin America. The urbanization of the T. cruzi transmission cycle necessitates new understanding of Chagas disease ecology and epidemiology, as well as new approaches to the surveillance, control, and prevention of vector infestation and parasite transmission. In rural La Joya, Peru, analyses highlight how the complexities of human migration and intermittent intervention influence the prevalence and incidence of Chagas disease. Substantial prevalence of T. cruzi infection was found in the adult population as a result of relatively higher incidence of infection among long-term inhabitants and relatively lower incidence of infection among short-term in-migrants. While an insecticide intervention in 1995 effectively eliminated incidence of infection among children, T. infestans and T. cruzi were rapidly reemerging in the absence of continuing vector control. In Arequipa, Peru, T. infestans had extensively and intensively infested an urban and peri-urban landscape prior to vector control. Environmental and social factors, which may directly or indirectly influence insect biology and behavior, were associated with infestation. Large clusters of infestation and spatial dependence among infested households at short and long distances suggest that T. infestans can disperse by crawling or flying in an urban environment, which may challenge ongoing vector surveillance and control. Reemergence of vector insects, including T. infestans, complicates continuing control of Chagas disease. While relatively rare, reemergence of T. infestans is a present and possibly persistent problem in urban and peri-urban Arequipa. The probability of a reemergence event varied spatially. Events were both clustered and non-clustered, and were spatially dependent at distances up to 1,600 meters. Event-to-event spatial proximity occurred at shorter distances in higher risk areas and longer distances in lower risk areas. Identifiable predictors and patterns of risk offer opportunities for more effective and efficient strategies for vector surveillance and control.

This dissertation consists of three papers that explore the intersection between geography and housing markets. The research examines both how geographic context shapes housing prices and how house prices influence geography through household location decisions.The first paper explores the spatial structure of housing prices within Tucson, Arizona. Hedonic house-price studies typically assume that housing attribute prices are constant over space. The research tests this assumption and compares two methods of incorporating spatial-varying parameters into house-price models: geographically weighted regression and the spatial expansion method. The results provide evidence that housing attribute prices do indeed vary with geographic context and suggest that more reliable parameter estimates and better house-price estimation accuracy can be achieved through the use of these techniques.The second paper builds upon the first by examining how more realistic conceptions of housing market spatial structure influence the hedonic price estimates of location-specific externalities. The empirical analysis examines how two key spatial effects, spatial dependence and spatial heterogeneity, impact the marginal price estimates for proximity to the Rillito River, within Tucson, Arizona. Both spatial effects are found to influence the resulting estimates, but spatial heterogeneity is of greater practical importance as the price estimates vary widely with geographic context. This research highlights the importance of considering both spatial effects in hedonic externality valuations.The final paper explores how housing prices influence interregional migration patterns, and more specifically, how their influence varies with both stage in the life course and educational attainment. The research models metropolitan migration within the United States during the period 1995 to 2000. The results indicate that housing prices play an important role in driving regional demographic change, as their influence varies with both demographic characteristics. High housing prices deter individuals in their late twenties and early thirties, but their influence wanes during middle age. House prices become more important as individuals near retirement. The results also provide evidence that college graduates respond more to house price differentials than do persons with lower levels of educational attainment.

Riparian systems are comprised of interacting aquatic and terrestrial elements that contribute distinctively to the natural capital of arid landscapes. Riparian vegetation is a major component of riparian systems, providing the ecosystem services required to support watershed health. The spatial and temporal distributions of riparian vegetation are influenced by hydrologic and disturbance processes operating at scales from local to regional. I believe both these processes are well suited to monitoring using synoptic and multitemporal approaches.The research in this dissertation is presented as 3 related studies. The first study focused on historical riparian dynamics related to natural disturbance and land use. Using current and historical riparian vegetation maps, we examined vegetation change within catchments of varying land use intensity. Results suggest that land use activities and wastewater subsidy affect the rate of development and diversity of riparian community typesThe second study used moderate resolution satellite imagery to monitor changes in riparian structure and pattern within a land cover change framework. We classified Landsat Thematic Mapper satellite imagery of the Upper Santa Cruz River watershed using Classification and Regression Tree (CART) models. We tested the ability of our models to capture change at landscape, floodplain, and catchment scales, centering our change detection efforts on a riparian tree die-off episode and found they can be used to describe both general landscape dynamics and disturbance-related riparian change.The third study examined historical and environmental factors contributing to spatial patterns of vegetation following two riparian tree die-offs. We used high resolution aerial imagery to map locations of individual live and dead trees and collected a suite of environmental variables and historical variables related directly and indirectly to land use and disturbance history. We tested for differences between groups of live and dead trees using Multi-response Permutation Procedures and found strong relationships between historical factors and mortality incidence.The results from these studies demonstrate the importance of examining historical information and spatial linkages across scales when monitoring riparian vegetation. From a land management perspective, the results identify the need for landscape-level, ecosystem-based management programs to maintain functioning and spatially connected riparian systems.

The main problem that is addressed in this thesis is how to represent complex three-dimensional objects in GIS in order to render a more realistic representation of the real world. The goal is to present an approach for representing complex 3D objects in GIS. This is achieved by using commercial GIS (ArcGIS), applied to 3D properties. In order to get a clear overview of the state-of-the-art of 3D GIS and the current 3D cadastral situation a literature study was carried out. Based on this overview it can be concluded that 3D GIS still is in its initial phase. Current 3D GIS developments are mainly in the area of visualisation and animation, and almost nothing in the area of spatial analysis and attribute handling. Furthermore, the literature study reveals that no complete solution has been introduced that solves the problems involved in 3D cadastral registration. In several countries (e.g. Sweden, Denmark, Norway, Netherlands, Israel, and Australia) 3D properties exists in a juridical framework, but technical issues such as how to represent, store, and visualize 3D properties has not yet been solved. Some countries (Sweden, Norway, and Australia) visualize the footprints of 3D property units in a base map. This approach partly solves some technical issues, but can only represent 3D objects in a 2.5D environment. Therefore, research in how to represent complex objects in GIS as ‘true’ 3D objects is of great need. This thesis will emphasize MultiPatch as a geographic representation method to represent complex 3D objects in GIS. A case study will demonstrate that complex objects can be visualized and analysed in a commercial GIS, in this case ArcGIS. Most commercial GIS software available on the market applies a 2.5D approach to represent 3D objects. The 2.5D approach has limitations for representing complex objects. There is therefore a need of finding new approaches to represent complex objects within GIS. The result shows that MultiPatch is not an answer to all the problems within 3D GIS but a solution to some of the problems. It still requires a lot of research in the field of 3D GIS, especially in development of spatial analysis capabilities. / Det huvudsakliga problemet i denna uppsats är hur komplexa tre-dimensionella objekt kan representeras i GIS för att återge verkligheten mer realistiskt. Målet är att presentera ett tillvägagångssätt för att representera komplexa 3D-objekt i GIS. Detta har uppnåtts genom att använda ett kommersiellt GIS tillämpat på 3D-fastigheter. En litteraturstudie har genomförts för att erhålla en klar översikt över det senaste inom 3D-GIS och över den aktuella situationen inom 3D-fastigheter. Grundat på översikten kan slutsatsen dras att 3D-GIS bara är i sin begynnelsefas. Den aktuella utvecklingen inom 3D-GIS har huvudsakligen fokuserat på visualisering och animering och nästan ingenting inom rumsliga analysmetoder och hantering av attribut. Litteraturstudien visar också att ingen fullständig lösning för de problem som finns inom 3D-fastighetsregistrering har introducerats. I flera länder, t.ex. Sverige, Danmark, Norge, Nederländerna, Israel och Australien, existerar 3D-fastigheter idag i juridiska termer, men de tekniska problemen som t.ex. hur 3D-fastigheter ska representeras, lagras och visualiseras har inte ännu lösts. Vissa länder (Sverige, Norge och Australien) visualiserar idag en projektion av 3D-fastigheterna på en fastighetskarta. Den här metoden löser endast några av de tekniska problemen och kan endast representera 3D-objekt i en 2,5D-miljö. Därför är forskning inom hur komplexa objekt kan representeras i GIS som s.k. ”sann” 3D av betydelse. Den här uppsatsen framhäver MultiPatch som en datatyp för att representera komplexa 3D-objekt i GIS. En fallstudie visar att komplexa objekt kan visualiseras och analyseras i ett kommersiellt GIS, i det här fallet ArcGIS. De flesta kommersiella GIS som är tillgängliga på marknaden använder 2,5D-metoden för att representera 3D-objekt. 2,5D-metoden har vissa begränsningar för att representera komplexa objekt och därför finns det ett behov att finna nya tillvägagångssätt för att representera komplexa objekt inom GIS. Resultaten kommer att visa att MultiPatch inte är någon fullständig lösning till alla problem inom 3D-GIS men en lösning på några av problemen. Det krävs fortfarande mycket forskning inom 3D-GIS, särskilt inom utveckling av rumsliga analysmetoder.

Soybean aphid, Aphis glycines Matsumura, is an important pest of North American soybean. This dissertation identifies and addresses knowledge gaps, and integrates existing knowledge regarding distribution and abundance of this species. Early summer soybean colonization patterns by A. glycines were examined relative to landscape parameters, including density of overwintering hosts (buckthorn). An information-theoretic model selection approach was used to determine which landscape parameters were most influential in the distribution of colonizing aphids. Though buckthorn abundance best explained aphid colonization and population density, a density-dependent effect was observed. When aphid populations were low, more aphids were found in the vicinity of buckthorn, when aphid populations were higher, more aphids were found farther from buckthorn. Suction trap captures of migrating populations of A. glycines from 2005-2009 from a suction trap network covering much of central North America were examined. A model selection approach was used to determine the environmental triggers of summer and fall aphid flights, and spatial analysis and modeled wind trajectories were used to examine patterns in the abundance of alates. Two alate activity peaks were observed in fall. In summer, formation of alates was a function of field infestation. A tritrophic population model was built using DYMEX, a mechanistic lifecycle based modeling software package. The model incorporated soybean, A. glycines, and three natural enemy species, interacting based on phenological, physiological and functional response data available in the literature. The model was validated using Ontario field data, and several simulations were performed and are discussed. An evaluation of proposed control strategies for efficacy and impact on natural enemies and the environment was conducted. Two novel concepts are presented: the natural enemy unit, a standardization of the impact of predator guild on prey populations by the number of prey an individual predator can eat, and the selectivity index, where the selectivity of a pesticide is a function of the change in ratio of natural enemy units to prey before and after treatment. The selectivity index was inversely correlated with the Environmental Impact Quotient (EIQ), a theoretical measure of impact, validating EIQ's field applicability. / Natural Sciences and Engineering Research Council of Canada; The Keefer family trust; the Mary Edmunds Williams trust, the family of Fred W. Presant, and the University of Guelph provided scholarship and fellowship funds. Research was funded by a grant to Rebecca Hallett and Art Schaafsma from the Agriculture and Agri-Food Canada Pest Management Centre’s Pesticide Risk Reduction Program.

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