| 1. |
- Asproth, Viveca, et al.
(författare)
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Dynamic information in GIS systems
- 1995
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier BV. - 0198-9715 .- 1873-7587. ; 19:2, s. 107-115
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Tidskriftsartikel (refereegranskat)abstract
- Time can be characterized as the fourth dimension of the physical space-time continuum. Time is either a particular instant at which a structure or a process exists or occurs, or a period over which a structure endures or a process continues. From the human point of view, a concrete system can move in any direction on the spatial dimension, but only forward on the temporal dimension. GIS systems generally deal with static information. Static objects can be defined as objects that do not change in a short time period. In many situations, the information in GIS applications does change dynamically. Environmental problems, for example, have a significant dynamic component, which means that the conditions of the real system, at the time the decision is made, are the results of all the past history of the system and influence its subsequent behavior. Dynamicallity in a process may be possible to measure. The measure should include components such as size of change, frequencies of change, and time interval. The dynamicallity of a system should, in addition, include the need of change in representation (for example, how often must the screen be updated) and how time-critical decisions are. Time can be represented by a series of snapshots, and the shorter time periods between the snapshots, the more it imitates a continuous course of events. The time lapse is represented by a minimum of two pictures, up to complete animation. Real time and presentation time are not necessarily the same, as it is desirable to shorten very long time lapses (for example geological changes), and lengthen (prolong) rapid time lapses (such as explosions). We define presentation time as a relation between observation interval (time interval between observations) and picture rate (the rate of changing pictures on the screen). In this paper, some functions for handling dynamic information in GIS systems are presented.
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| 2. |
- Asproth, Viveca, et al.
(författare)
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GIS-application for visualization of streams
- 1994
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier. - 0198-9715 .- 1873-7587. ; 18:2, s. 103-109
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Tidskriftsartikel (refereegranskat)abstract
- Up to now, GIS systems have been used to produce maps. When using these maps, for example, to look at a road section, you are limited to one map-sheet at a time with a specific scale. A common application, for example, in communities and electricity companies, is to include networks such as water pipes, sewage systems, and electric mains. As the lines cross map-sheet borders, it has been necessary to put the map-sheets together. It is useful for communities to have up-to-date and accurate information about water pipes, to be able to locate leaks and to know where to cut off the lines and to know which consumers are affected, when repairing. In the future, GIS systems could also be used as decision and planning support. To be able to use GIS systems for this purpose, it is necessary to improve techniques for visualization of streams (direction and strength) over time. This paper describes a project that aims to develop and evaluate user interfaces for visualization of all kinds of streams and to improve and evaluate methods and CASE tools for development of GIS applications.
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| 3. |
- Le Duc, Michael
(författare)
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A Command Model for Executive Informatics Based on Living Systems Theory
- 1993
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier BV. - 0198-9715 .- 1873-7587. ; 17:5, s. 385-392
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Tidskriftsartikel (refereegranskat)abstract
- The Command Model presented here was developed in a project for designing executive informatic systems (EIS) balancing technical and human dimensions contracted by the Swedish National Board of Civil Emergency Preparedness (OCB). The contract explicitly emphasised new ideas, rather than piecemeal improvements of existing technology and procedures. The model focuses the intermediate level between operations and strategy. Executive informatics (EI) encompasses information technology and its use at top-level management, as contrasted with administrative or operative informatic systems. The Command Model categorises the four most frequent and important processes of tactical command and is based on symbols from Living Systems Theory (Miller 1978, Miller & Miller 1990). It can be implemented in software to be used as a front-end to operative informatic systems for command purposes.
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| 4. |
- Le Duc, Michael
(författare)
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A Design Methodology for GeoInformatic Systems
- 1992
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Ingår i: COMPUTERS ENVIRONMENT AND URBAN SYSTEMS. - : Elsevier BV. - 0198-9715. ; 16:5, s. 403-413
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims at complementing the craft of geographical information systems (GIS) professionals with methodology founded in the systems sciences. GeoInformatics (GeoI) is conceptualized as more problem-oriented than most current GIS methodologies, which are rather technical. Conceptual considerations relevant for GeoI are made, the most important being that a GeoInformatic System (GeoIS) is a concrete implementation of GeoI concepts. The problems of information system design in general and GIS design in particular are conceptualized. A theoretical framework, Living Systems Theory (Miller 1978), is presented as a base to modeling the concrete systems handled in GeoI Modeling is conceptualized as a continuous process between the concrete and the conceptual. Design is made on models that are subsequently implemented. Implementation is facilitated by prototyping. A ten-step formulation of the design methodology is presented.
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| 5. |
- Abascal, Angela, et al.
(författare)
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Identifying degrees of deprivation from space using deep learning and morphological spatial analysis of deprived urban areas
- 2022
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier BV. - 0198-9715 .- 1873-7587. ; 95
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Tidskriftsartikel (refereegranskat)abstract
- Many cities in low- and medium-income countries (LMICs) are facing rapid unplanned growth of built-up areas, while detailed information on these deprived urban areas (DUAs) is lacking. There exist visible differences in housing conditions and urban spaces, and these differences are linked to urban deprivation. However, the appropriate geospatial information for unravelling urban deprivation is typically not available for DUAs in LMICs, constituting an urgent knowledge gap. The objective of this study is to apply deep learning techniques and morphological analysis to identify degrees of deprivation in DUAs. To this end, we first generate a reference dataset of building footprints using a participatory community-based crowd-sourcing approach. Secondly, we adapt a deep learning model based on the U-Net architecture for the semantic segmentation of satellite imagery (WorldView 3) to generate building footprints. Lastly, we compute multi-level morphological features from building footprints for identifying the deprivation variation within DUAs. Our results show that deep learning techniques perform satisfactorily for predicting building footprints in DUAs, yielding an accuracy of F1 score = 0.84 and Jaccard Index = 0.73. The resulting building footprints (predicted buildings) are useful for the computation of morphology metrics at the grid cell level, as, in high-density areas, buildings cannot be detected individually but in clumps. Morphological features capture physical differences of deprivation within DUAs. Four indicators are used to define the morphology in DUAs, i.e., two related to building form (building size and inner irregularity) and two covering the form of open spaces (proximity and directionality). The degree of deprivation can be evaluated from the analysis of morphological features extracted from the predicted buildings, resulting in three categories: high, medium, and low deprivation. The outcome of this study contributes to the advancement of methods for producing up-to-date and disaggregated morphological spatial data on urban DUAs (often referred to as 'slums') which are essential for understanding the physical dimensions of deprivation, and hence planning targeted interventions accordingly.
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| 6. |
- Aslani, Mohammad, et al.
(författare)
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Rooftop segmentation and optimization of photovoltaic panel layouts in digital surface models
- 2023
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier. - 0198-9715 .- 1873-7587. ; 105
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Tidskriftsartikel (refereegranskat)abstract
- Rooftop photovoltaic panels (RPVs) are being increasingly used in urban areas as a promising means of achieving energy sustainability. Determining proper layouts of RPVs that make the best use of rooftop areas is of importance as they have a considerable impact on the RPVs performance in efficiently producing energy. In this study, a new spatial methodology for automatically determining the proper layouts of RPVs is proposed. It aims to both extract planar rooftop segments and identify feasible layouts with the highest number of RPVs in highly irradiated areas. It leverages digital surface models (DSMs) to consider roof shapes and occlusions in placing RPVs. The innovations of the work are twofold: (a) a new method for plane segmentation, and (b) a new method for optimally placing RPVs based on metaheuristic optimization, which best utilizes the limited rooftop areas. The proposed methodology is evaluated on two test sites that differ in urban morphology, building size, and spatial resolution. The results show that the plane segmentation method can accurately extract planar segments, achieving 88.7% and 99.5% precision in the test sites. In addition, the results indicate that complex rooftops are adequately handled for placing RPVs, and overestimation of solar energy potential is avoided if detailed analysis based on panel placement is employed.
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| 7. |
- Chen, Kun, et al.
(författare)
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Towards healthcare access equality : Understanding spatial accessibility to healthcare services for wheelchair users
- 2024
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Ingår i: Computers, Environment and Urban Systems. - 0198-9715. ; 108
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Tidskriftsartikel (refereegranskat)abstract
- Considering that the number of wheelchair users is on the rise at the global level due to population aging, it is crucial to secure their rights to have adequate access to healthcare services. Spatial accessibility to healthcare services has been well recognized to influence people's health. However, research on healthcare accessibility of wheelchair users is scarce. This study proposes a barrier-free path planning method to estimate wheelchair users' travel time as the measurement of their accessibility. A study on Wuhan, China, is conducted to evaluate the spatial accessibility to healthcare services for wheelchair users and compare it with the general population. The results show that: (1) the levels of healthcare accessibility are unevenly distributed across the city center and the periphery of the study area for both wheelchair users and the general population, while wheelchair users have lower accessibility overall; (2) both similarities and differences in hospital and travel mode selection to access healthcare services co-exist in the study area between the two groups; (3) significant inequality in healthcare accessibility is observed in Hongshan and Qingshan districts. The research findings are beneficial for policymakers to further improve healthcare accessibility and its equality by optimizing the allocation of hospital resources and barrier-free public transport.
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| 8. |
- Farnaghi, Mahdi, et al.
(författare)
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Disaster planning using automated composition of semantic OGC web services: A case study in sheltering
- 2013
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier BV. - 0198-9715. ; 41, s. 204-218
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Tidskriftsartikel (refereegranskat)abstract
- Spatial data are crucial in disaster planning. However, because of the dynamic, urgent and uncertain nature of disasters, certain data and functionalities may be inaccessible to decision makers when they are required. Web service composition offers a possible solution whereby disaster planners can integrate spatial web services to generate new spatial data and functionalities, quickly, from existing ones. This paper proposes an automatic solution for composing OWSs (Open Geospatial Consortium Web Services) for disaster planning. A semantic annotation approach based on the Resource Description Framework (RDF) and SPARQL languages is used to describe OWSs semantically. A conceptual model for AI (Artificial Intelligence) planning is also proposed that works based on RDF and SPARQL. An AI planning algorithm was implemented based on the proposed conceptual model to compose semantic OWSs. The applicability of the proposed solution is investigated through a case study in evacuation sheltering. The case study demonstrates that the proposed automatic composition approach can enhance the efficiency of OWS integration and thereby improve the disaster management process. (c) 2013 Elsevier Ltd. All rights reserved.
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| 9. |
- Feng, Chen, et al.
(författare)
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Predicting and mapping neighborhood-scale health outcomes : A machine learning approach
- 2021
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier BV. - 0198-9715. ; 85
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Tidskriftsartikel (refereegranskat)abstract
- Estimating health outcomes at a neighborhood scale is important for promoting urban health, yet costly and time-consuming. In this paper, we present a machine-learning-enabled approach to predicting the prevalence of six common non-communicable chronic diseases at the census tract level. We apply our approach to the City of Austin and show that our method can yield fairly accurate predictions. In searching for the best predictive models, we experiment with eight different machine learning algorithms and 60 predictor variables that characterize the social environment, the physical environment, and the aspects and degrees of neighborhood disorder. Our analysis suggests that (a) the sociodemographic and socioeconomic variables are the strongest predictors for tract-level health outcomes and (b) the historical records of 311 service requests can be a useful complementary data source as the information distilled from the 311 data often helps improve the models' performance. The machine learning models yielded from this study can help the public and city officials evaluate future scenarios and understand how changes in the neighborhood conditions can lead to changes in the health outcomes. By analyzing where the most significant discrepancies between the predicted and the actual values are, we will also be ready to identify areas of best practice and areas in need of greater investment or policy intervention.
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| 10. |
- Fonseca, Jimeno A., et al.
(författare)
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Spatial heterogeneity for environmental performance and resilient behavior in energy and transportation systems
- 2017
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Ingår i: Computers, Environment and Urban Systems. - : Elsevier BV. - 0198-9715. ; 62, s. 136-145
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes an assessment of the effects of spatial heterogeneity on the future performance and resilience of an urban area. For this, indicators of environmental performance and resilience of critical infrastructures (energy and transportation systems) are explored. The approach combines established methododologies of building performance simulation, energy systems analysis, and environmental impact assessment of buildings and transportation systems. The study is centered on future urban design scenarios for an industrial neighborhood in Switzerland. For this case study, multi-functionality is proportional to the performance and resilience of critical infrastructures. Mono-functionality improves the resilience and performance of energy systems with a negative effect on that of transportation systems. Building intensity, and resource intensive users were found to play a higher role into the future performance and resilience of the area. The findings of this research could complement planning approaches of sustainable and resilient urban areas.
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