Effects of Spatial Pattern of GreenSpace on Land Surface Temperature: A case study on Oasis City Aksu, northwest China

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.The urban heat island (UHI) refers to the phenomenon of higher atmospheric and surface temperatures occurring in urban areas than in the surrounding rural areas. Numerous studies have shown that increased percent cover of greenspace (PLAND) can significantly decrease land surface temperatures (LST). Fewer studies, however, have investigated the effects of configuration of greenspace on LST. This thesis aims to fill this gap using oasis city Aksu, northwest China as a case study. PLAND along with two configuration metrics were used to measure the composition and configuration of greenspace. The metrics were calculated by moving window method based on a greenspace map derived from Landsat Thematic Mapper (TM) imagery, and LST data were retrieved from Landsat TM thermal band. Normalized mutual information measure was employed to investigate the relationship between LST and the spatial pattern of greenspace. The results showed that PLAND was the most important predictor of LST. Configuration of greenspace also significantly affected LST. In addition, the variance of LST was largely explained by both composition and configuration of greenspace. Results from this study can expand our understanding of the relationship between LST and vegetation, and provide insights for improving urban greenspace planning and management

Temporality in Hillier and Hanson's Theory of Spatial Description: Some Implications Of Historical Research For Space Syntax

This paper proposes that Hillier and Hanson's thought on society and space has wider applications for social theory in general and or applied historical research in particular than has previously been acknowledged. This epistemological isolation can, to an extent, be explained pragmatically by the inevitable difficulties of inter-disciplinary translation of historical research conducted in space syntax mode. However, the principle concern of this paper is to explore a more fundamental, theoretical, reason why researchers in the historical disciplines can struggle to engage with Hillier and Hanson's work: namely the marginalization of temporality in the 'theory of spatial description' that is the conceptual foundation of the space syntax theory. The claim is not that time has been altogether ignored; on the contrary the temporal nature of reality figures largely in the theory. Rather, the argument here is that this aspect of the theory has, in practice, been deliberately subordinated to the overriding task of articulating a formal morphological grammar of social organization. Perhaps inevitably this emphasis has focused attention on the synchronic structure of space, to which notions of temporality remained essentially external. However, it is equally clear that this emphasis has come at the cost of introducing some inconsistencies in the underlying theoretical proposition of spatial description. The consequence, it is claimed, has been to amplify the difficulty in using Hillier and Hanson to articulate temporality in space. This difficulty raises issues not only for those with a particular concern in built environment history but, more generally, with anyone concerned to understand the complex relationship of architectural space to how people live. Through a critical review of space syntax theory and its intellectual antecedents in the light of what could be termed the 'temporal turn' in the physical sciences, this paper makes the case for time-space descriptions as a natural development of Hillier and Hanson's theory of spatial description that is necessary if space syntax research wishes to extend its engagement with the historical disciplines

Analysing the visual dynamics of spatial morphology

Recently there has been a revival of interest in visibility analysis of architectural configurations. The new analyses rely heavily on computing power and statistical analysis, two factors which, according to the postpositivist school of geography, should immediately cause us to be wary. Thedanger, they would suggest, is in the application of a reductionist formal mathematical description in order to `explain' multilayered sociospatial phenomena. The author presents an attempt to rationalise how we can use visibility analysis to explore architecture in this multilayered context by considering the dynamics that lead to the visual experience. In particular, it is recommended that we assess the visualprocess of inhabitation, rather than assess the visibility in vacuo. In order to investigate the possibilities and limitations of the methodology, an urban environment is analysed by means of an agent-based model of visual actors within the configuration. The results obtained from the model are compared with actual pedestrian movement and other analytic measurements of the area: the agents correlate well both with human movement patterns and with configurational relationship as analysed by space-syntax methods. The application of both methods in combination improves on the correlation with observed movement of either, which in turn implies that an understanding of both the process of inhabitation and the principles of configuration may play a crucial role in determining the social usage of space

Effects of green space spatial pattern on land surface temperature: Implications for sustainable urban planning and climate change adaptation

The urban heat island (UHI) refers to the phenomenon of higher atmospheric and surface temperatures occurring in urban areas than in the surrounding rural areas. Mitigation of the UHI effects via the configuration of green spaces and sustainable design of urban environments has become an issue of increasing concern under changing climate. In this paper, the effects of the composition and configuration of green space on land surface temperatures (LST) were explored using landscape metrics including percentage of landscape (PLAND), edge density (ED) and patch density (PD). An oasis city of Aksu in Northwestern China was used as a case study. The metrics were calculated by moving window method based on a green space map derived from Landsat Thematic Mapper (TM) imagery, and LST data were retrieved from Landsat TM thermal band. A normalized mutual information measure was employed to investigate the relationship between LST and the spatial pattern of green space. The results showed that while the PLAND is the most important variable that elicits LST dynamics, spatial configuration of green space also has significant effect on LST. Though, the highest normalized mutual information measure was with the PLAND (0.71), it was found that the ED and PD combination is the most deterministic factors of LST than the unique effects of a single variable or the joint effects of PLAND and PD or PLAND and ED. Normalized mutual information measure estimations between LST and PLAND and ED, PLAND and PD and ED and PD were 0.7679, 0.7650 and 0.7832, respectively. A combination of the three factors PLAND, PD and ED explained much of the variance of LST with a normalized mutual information measure of 0.8694. Results from this study can expand our understanding of the relationship between LST and street trees and vegetation, and provide insights for sustainable urban planning and management under changing climat

Assessment of Levee Erosion using Image Processing and Contextual Cueing

Soil erosion is one of the most severe land degradation problems afflicting many parts of the world where topography of the land is relatively steep. Due to inaccessibility to steep terrain, such as slopes in levees and forested mountains, advanced data processing techniques can be used to identify and assess high risk erosion zones. Unlike existing methods that require human observations, which can be expensive and error-prone, the proposed approach uses a fully automated algorithm to indicate when an area is at risk of erosion; this is accomplished by processing Landsat and aerial images taken using drones. In this paper the image processing algorithm is presented, which can be used to identify the scene of an image by classifying it in one of six categories: levee, mountain, forest, degraded forest, cropland, grassland or orchard. This paper focuses on automatic scene detection using global features with local representations to show the gradient structure of an image. The output of this work counts as a contextual cueing and can be used in erosion assessment, which can be used to predict erosion risks in levees. We also discuss the environmental implications of deferred erosion control in levees

Dwelling on ontology - semantic reasoning over topographic maps

The thesis builds upon the hypothesis that the spatial arrangement of topographic features, such as buildings, roads and other land cover parcels, indicates how land is used. The aim is to make this kind of high-level semantic information explicit within topographic data. There is an increasing need to share and use data for a wider range of purposes, and to make data more definitive, intelligent and accessible. Unfortunately, we still encounter a gap between low-level data representations and high-level concepts that typify human qualitative spatial reasoning. The thesis adopts an ontological approach to bridge this gap and to derive functional information by using standard reasoning mechanisms offered by logic-based knowledge representation formalisms. It formulates a framework for the processes involved in interpreting land use information from topographic maps. Land use is a high-level abstract concept, but it is also an observable fact intimately tied to geography. By decomposing this relationship, the thesis correlates a one-to-one mapping between high-level conceptualisations established from human knowledge and real world entities represented in the data. Based on a middle-out approach, it develops a conceptual model that incrementally links different levels of detail, and thereby derives coarser, more meaningful descriptions from more detailed ones. The thesis verifies its proposed ideas by implementing an ontology describing the land use ‘residential area’ in the ontology editor Protégé. By asserting knowledge about high-level concepts such as types of dwellings, urban blocks and residential districts as well as individuals that link directly to topographic features stored in the database, the reasoner successfully infers instances of the defined classes. Despite current technological limitations, ontologies are a promising way forward in the manner we handle and integrate geographic data, especially with respect to how humans conceptualise geographic space

The cognitive roots of space syntax

During the last twenty-five years of research and real-world studies accomplished all over the globe, space syntax has consistently shown that movement patterns in cities and buildings tend to be strongly related to configurational properties of their respective spatial layouts. It has also been shown that individuals’ trajectories in virtual worlds are affected by the syntactic properties of these environments, and that the resulting emergent patterns may explain the detected correlations between configurational properties of space and movement patterns in real-world scenarios. However, none of these studies have so far attempted to elicit why these regularities occur at a more fundamental, cognitive level. In other words, they have not yet answered how the idea of spatial configuration shapes a person’s qualitative assessments and subsequent usage of spatial networks. This is the topic of this thesis. What kind of information do people extract from spatial configurations? How is this information used when assessing a spatial network qualitatively? How is this information used when one has to use such a network? These are some of the questions that this thesis will attempt to answer. This thesis will focus on map usage. By analysing how people interact with maps, this thesis will attempt to shed light on the processes by which people internalise configurational information and are able to define qualitative judgements that may be use in real-world scenarios. As a result, this thesis aims to be a further step in the ongoing process of linking space syntax with cognitive theory and therefore to contribute in the search of the cognitive roots of space syntax

Rapid configurational analysis using OSM data: towards the use of Space Syntax to orient post-disaster decision making

This paper addresses the problem of the growing exposure of contemporary cities to natural hazards by discussing the theoretical, methodological and practical aspects of using the configurational approach as a framework to perform a variety of spatial analyses to better orient disaster management. It claims that enabling a quick assessment of the evolving spatial functioning of the urban grid would effectively contribute to support strategic decision-making and to make post-disaster planning decisions more explicit among stakeholders, thus boosting wider understanding and participation among the public. The paper starts with a brief review of some relevant work done by the research community to date, which highlights emergent opportunities for urban morphology studies and Space Syntax theory to trigger effective innovations in disaster management practice. Next, the paper proposes to adopt a fit-for-purpose analysis approach with the aim to achieve a higher procedural flexibility in the analysis workflow. This issue is treated with a special focus on the necessities of relief organisations which need to integrate and overlap numerous layers of information and consider the feasibility of the analysis by evaluating time and costs. The proposal considers the economy of the construction of the map to be fundamental for ensuring the feasibility of a quantitative spatial assessment in data scarce contexts such as cities affected by disasters. Moreover, it recognises that the unicity of the map is likely to enable a better communication among different stakeholders following a BIM-oriented model of cooperation, while allowing a faster response in multi-hazards scenarios. Consequently, the proposal challenges the idea of the existence of a uniquely correct way to translate reality into a model, but rather suggests using a set of simplification techniques, such as filtering, generalisation and re-modelling, on a single crowdsourced map of the urban street network to generate suitably customised graphs for subsequent analysis. This brings together two themes: the first concerns the modelling activity per se and how certain technicalities that seem minor facts can influence the final analysis output to a greater extent; the second regards the crowdsourcing of spatial data and the challenges that the use of collaborative datasets poses to the modelling tasks. In line with the most recent research trends, this paper suggests exploiting the readiness of the Open Street Map (OSM) geo-dataset and the improving computational capacities of open GIS tools such as QGIS, which has recently achieved a wider acceptance worldwide. To further speed up the analysis and increase the likeness of the configurational analysis method to be successfully deployed by a larger pool of professionals it also proposes to make use of a state-of-the-art Python library named OSMnx. In the end, the consequences of using Volunteered Geographic Information (VGI), open source GIS platforms and Python scripting to perform the analysis are illustrated in a set of suitable case studies

Technology assessment of advanced automation for space missions

Six general classes of technology requirements derived during the mission definition phase of the study were identified as having maximum importance and urgency, including autonomous world model based information systems, learning and hypothesis formation, natural language and other man-machine communication, space manufacturing, teleoperators and robot systems, and computer science and technology