| 1. |
- Mansourian, Ali, et al.
(författare)
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Geospatial Technologies for All: Preface
- 2018
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Ingår i: Geospatial technologies for all : Selected Papers of the 21st AGILE Conference on Geographic Information Science - Selected Papers of the 21st AGILE Conference on Geographic Information Science. - Cham : Springer International Publishing. - 1863-2246 .- 1863-2351. - 9783319782072 - 9783319782089 ; part F3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Oriangi, George, et al.
(författare)
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Household resilience to climate change hazards in Uganda
- 2020
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Ingår i: International Journal of Climate Change Strategies and Management. - : EMERALD GROUP PUBLISHING LTD. - 1756-8692 .- 1756-8706. ; 12:1, s. 59-73
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Tidskriftsartikel (refereegranskat)abstract
- Purpose As climate change shocks and stresses increasingly affect urban areas in developing countries, resilience is imperative for the purposes of preparation, recovery and adaptation. This study aims to investigate demographic characteristics and social networks that influence the household capacity to prepare, recover and adapt when faced with prolonged droughts or erratic rainfall events in Mbale municipality in Eastern Uganda. Design/methodology/approach A cross-sectional research design was used to elicit subjective opinions. Previous studies indicate the importance of subjective approaches for measuring social resilience but their use has not been well explored in the context of quantifying urban resilience to climate change shocks and stresses. This study uses 389 structured household interviews to capture demographic characteristics, social networks and resilience capacities. Descriptive and inferential statistics were used for analysis. Findings The ability of low-income households to meet their daily expenditure needs, household size, and networks with relatives and non government organizations (NGOs) were significant determinants of preparedness, recovery and adaptation to prolonged droughts or erratic rainfall events. Originality/value Even the low-income households are substantially more likely to prepare for and recover from prolonged droughts or erratic rainfall events if they can meet their daily expenditure needs. This finding is noteworthy because the poorest in society are generally the most vulnerable to hazards.
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| 3. |
- Pilesjö, Petter, et al.
(författare)
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Analys av geografiska data
- 2020. - 7:1
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Ingår i: Geografisk informationsbehandling: : teori, metoder och tillämpningar - teori, metoder och tillämpningar. - 9789144131740 ; , s. 215-272
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- I detta kapitel i boken Geografisk information Behandling beskrivs och behandlas metoder för hur geografisk data analyseras. Kapitlet omfattar såväl geografisk teori som exempel på tillämpningar. Geografisk informationsbehandling baseras på insamling, lagring, analys och visualisering av geografiska data. Denna indelning utgör också grunden för bokens disposition. Boken är i första hand avsedd för introducerande kurser vid universitet och högskolor men vissa delar är lämpliga även på avancerad nivå. Den är också utmärkt för yrkesverksamma inom GIS som vill öka sina teoretiska kunskaper.Boken innehåller både teoretiska och praktiska delar, där de senare beskriver tillämpningar som exempelvis samhällsplanering, miljöövervakning och kommersiella tjänster. I insamlingsdelen beskrivs hur man anger en position genom att koppla ett koordinatsystem till jordytan. Därefter beskrivs de vanligaste metoderna att samla in geografiska data som satellitbaserade positioneringssystem, flygfotografering, satellitbaserad fjärranalys och laserskanning. Lagringsdelen behandlar hur dessa data lagras i databaser och distribueras via webben. Analysdelen innehåller beskrivningar av de vanligaste analysmetoderna samt kvalitetsfrågor. Resultatet av en geografisk analys visualiseras oftast i form av kartor, vilket är temat för den sista delen av boken.Denna sjunde upplaga har uppdaterats med nya aktuella tillämpningsexempel. Dessa är i denna upplaga beskrivna tillsammans med de teoretiska beskrivningarna för att stärka kopplingen mellan teori och tillämpningar. Dessutom har beskrivningen av webbtillämpningar utökats och utgör nu ett eget kapitel, och även texten om webbvisualiseringar har stärkts i kartografikapitlet. Vidare har det tillkommit beskrivningar av nya mättekniker samt texter om lagring, analys och visualisering av 3D geografiska data.
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| 4. |
- Nilsson, Hampus, et al.
(författare)
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Dynamic spatio‐temporal flow modeling with raster DEMs
- 2022
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Ingår i: Transactions in GIS. - : Wiley. - 1467-9671 .- 1361-1682. ; 26:3, s. 1572-1588
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Tidskriftsartikel (refereegranskat)abstract
- A user-friendly high-resolution intermediate complexity dynamic and spatially distributed flow model is crucial in urban flood modeling. Planners and consultants need to improve the accuracy of floods and estimation of risks. A new flow model will serve as a rapid tool to improve identification of these. This article provides a detailed explanation of a model based on a multiple flow algorithm. Model testing was performed on selected urban and rural areas. Additionally, a sensitivity analysis is conducted to analyze functionality. The model includes basic hydrological processes and is therefore less complex than fully physical models. The data needed to set up and run the new model include spatially and temporally distributed basic geometric and hydrologic variables (i.e., digital elevation model, precipitation, infiltration, and surface roughness). The model is implemented using open-source coding and can easily be applied to any selected area. Outputs are water volumes, depths, and velocities at different modeling times. Using GIS, results can be visualized and utilized for further analyses. The test, applied in urban as well as rural areas, demonstrates its user-friendliness, and that the estimated distributed water depths and water velocity at any time step can be saved and visualized.
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| 5. |
- MZOBE, Pearl, et al.
(författare)
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Dissolved organic carbon in streams within a subarctic catchment analysed using a GIS/remote sensing approach
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- Climate change projections show that temperature and precipitation increases can alter the exchange of greenhouse gases between the atmosphere and high latitude landscapes, including their freshwaters. Dissolved organic carbon (DOC) plays an important role in greenhouse gas emissions, but the impact of catchment productivity on DOC release to subarctic waters remains poorly known, especially at regional scales. We test the hypothesis that increased terrestrial productivity, as indicated by the normalized difference vegetation index (NDVI), generates higher stream DOC concentrations in the Stordalen catchment in subarctic Sweden. Furthermore, we aimed to determine the degree to which other generic catchment properties (elevation, slope) explain DOC concentration, and whether or not land cover variables representing the local vegetation type (e.g., mire, forest) need to be included to obtain adequate predictive models for DOC delivered into rivers. We show that the land cover type, especially the proportion of mire, played a dominant role in the catchment's release of DOC, while NDVI, slope, and elevation were supporting predictor variables. The NDVI as a single predictor showed weak and inconsistent relationships to DOC concentrations in recipient waters, yet NDVI was a significant positive regulator of DOC in multiple regression models that included land cover variables. Our study illustrates that vegetation type exerts primary control in DOC regulation in Stordalen, while productivity (NDVI) is of secondary importance. Thus, predictive multiple linear regression models for DOC can be utilized combining these different types of explanatory variables.
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| 6. |
- Tang, Jing, et al.
(författare)
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Investigating the influence of two different flow routing algorithms on soil-water-vegetation interactions using the dynamic ecosystem model LPJ-GUESS
- 2015
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Ingår i: Ecohydrology. - : Wiley. - 1936-0584 .- 1936-0592. ; 8:4, s. 570-583
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Tidskriftsartikel (refereegranskat)abstract
- This paper compares two flow routing algorithms' influences on ecohydrological estimations in a northern peatland catchment, within the framework of an arctic-enabled version of the dynamic ecosystem model LPJ-GUESS. Accurate hydrological estimations are needed to fully capture vegetation dynamics and carbon fluxes in the subarctic peatland enviroment. A previously proposed distributed hydrological method based on the single flow (SF) algorithm extracted topographic indices has shown to improve runoff estimations in LPJ-GUESS. This paper investigates model performance differences caused by two flow routing algorithms, and importantly both permafrost processes and peatland hydrology are included in the model. The newly developed triangular form-based multiple flow (TFM) is selected due to its improved consideration of flow continuity and more realistic flow estimation over flat surfaces. A variety of measured data is included to assess both hydrological and ecological accuracy, and the results demonstrate that the choice of flow algorithm does matter for mesoscale ecohydrology applications. The allowance of flow convergence and consideration of flow partition differences from different terrain forms in the TFM algorithm yield better correspondence with the observed hydrological processes and also carbon fluxes. By directing flow to only one downslope cell together with its poorer depiction of flow over flat areas, the SF algorithm can result in too high runoff estimations for low-flat regions and overestimate carbon uptake and release in the peatland. The results of this study also highlight the need for care when selecting flow routing algorithms for biogeochemical estimations, especially within hydrologically and climatically sensitive environments.
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| 7. |
- Eklöf, Martin, et al.
(författare)
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OPENLAND3: a computer program to estimate plant abundance around pollen sampling sites from vegetation maps: a necessary step for calculation of pollen productivity estimates
- 2004
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Ingår i: Review of Palaeobotany and Palynology. - : Elsevier BV. - 0034-6667. ; 132:1-2, s. 67-77
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Tidskriftsartikel (refereegranskat)abstract
- OPENLAND3 belongs to a suite of computer programs included in the POLLSCAPE simulation model. These programs make it possible to calculate estimates of pollen loadings in lake basins or bogs using vegetation data. OPENLAND3, written in Visual Basic 6, is designed to produce appropriate vegetation data files from vegetation maps stored in a Geographical Information System. It calculates percentage cover of plant taxa in concentric circles at increasing distances from a central point, using either real digitised maps or hypothetical maps (simulated landscape designs). Such data are necessary for simulation of pollen dispersal and deposition, and for calculation of pollen productivity estimates and relevant source area of pollen using specific mathematical models developed by palynologists, such as the Prentice-Sugita model. OPENLAND3 also produces output files needed to run RS-OPEN, another program included in POLLSCAPE, in order to obtain estimates of pollen loadings in lakes or bogs. The rationale of OPENLAND3, the algorithm used, and a modification of RS-OPEN (RS-OPEN2) are described. A test of the programme capability using a detailed vegetation map from southern Sweden shows that simulations using OPENLAND3 produce coherent results. Pollen loading for species characterized by high pollen productivity is higher than for species with low pollen productivity. Altering the wind speed has also a significant effect on pollen loading. As wind speed increases, the proportions of the light pollen decrease, while the heavy pollen types increase, which is what empirical data suggest, and what the model predicts in earlier studies. (C) 2004 Elsevier B.V. All rights reserved.
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| 8. |
- Aturinde, Augustus, et al.
(författare)
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Spatial analysis of HIV-TB co-clustering in Uganda
- 2019
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Ingår i: BMC Infectious Diseases. - : Springer Science and Business Media LLC. - 1471-2334. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Tuberculosis (TB) is the leading cause of death for individuals infected with Human immunodeficiency virus (HIV). Conversely, HIV is the most important risk factor in the progression of TB from the latent to the active status. In order to manage this double epidemic situation, an integrated approach that includes HIV management in TB patients was proposed by the World Health Organization and was implemented in Uganda (one of the countries endemic with both diseases). To enable targeted intervention using the integrated approach, areas with high disease prevalence rates for TB and HIV need to be identified first. However, there is no such study in Uganda, addressing the joint spatial patterns of these two diseases.METHODS: This study uses global Moran's index, spatial scan statistics and bivariate global and local Moran's indices to investigate the geographical clustering patterns of both diseases, as individuals and as combined. The data used are TB and HIV case data for 2015, 2016 and 2017 obtained from the District Health Information Software 2 system, housed and maintained by the Ministry of Health, Uganda.RESULTS: Results from this analysis show that while TB and HIV diseases are highly correlated (55-76%), they exhibit relatively different spatial clustering patterns across Uganda. The joint TB/HIV prevalence shows consistent hotspot clusters around districts surrounding Lake Victoria as well as northern Uganda. These two clusters could be linked to the presence of high HIV prevalence among the fishing communities of Lake Victoria and the presence of refugees and internally displaced people camps, respectively. The consistent cold spot observed in eastern Uganda and around Kasese could be explained by low HIV prevalence in communities with circumcision tradition.CONCLUSIONS: This study makes a significant contribution to TB/HIV public health bodies around Uganda by identifying areas with high joint disease burden, in the light of TB/HIV co-infection. It, thus, provides a valuable starting point for an informed and targeted intervention, as a positive step towards a TB and HIV-AIDS free community.
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| 9. |
- Niyomubyeyi, Olive, et al.
(författare)
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Evacuation planning optimization based on a multi-objective artificial bee colony algorithm
- 2019
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Ingår i: ISPRS International Journal of Geo-Information. - : MDPI AG. - 2220-9964. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- Evacuation is an important activity for reducing the number of casualties and amount of damage in disaster management. Evacuation planning is tackled as a spatial optimization problem. The decision-making process for evacuation involves high uncertainty, conflicting objectives, and spatial constraints. This study presents a Multi-Objective Artificial Bee Colony (MOABC) algorithm, modified to provide a better solution to the evacuation problem. The new approach combines random swap and random insertion methods for neighborhood search, the two-point crossover operator, and the Pareto-based method. For evacuation planning, two objective functions were considered to minimize the total traveling distance from an affected area to shelters and to minimize the overload capacity of shelters. The developed model was tested on real data from the city of Kigali, Rwanda. From computational results, the proposed model obtained a minimum fitness value of 5.80 for capacity function and 8.72 × 10 8 for distance function, within 161 s of execution time. Additionally, in this research we compare the proposed algorithm with Non-Dominated Sorting Genetic Algorithm II and the existing Multi-Objective Artificial Bee Colony algorithm. The experimental results show that the proposed MOABC outperforms the current methods both in terms of computational time and better solutions with minimum fitness values. Therefore, developing MOABC is recommended for applications such as evacuation planning, where a fast-running and efficient model is needed.
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| 10. |
- Mohammadi, Babak, et al.
(författare)
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Improving glacio-hydrological model calibration and model performance in cold regions using satellite snow cover data
- 2024
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Ingår i: Applied water science. - 2190-5487. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- Hydrological modeling realism is a central research question in hydrological studies. However, it is still a common practice to calibrate hydrological models using streamflow as a single hydrological variable, which can lead to large parameter uncertainty in hydrological simulations. To address this issue, this study employed a multi-variable calibration framework to reduce parameter uncertainty in a glacierized catchment. The current study employed multi-variable calibration using three different calibration schemes to calibrate a glacio-hydrological model (namely the FLEXG) in northern Sweden. The schemes included using only gauged streamflow data (scheme 1), using satellite snow cover area (SCA) derived from MODIS data (scheme 2), and using both gauged streamflow data and satellite SCA data as references for calibration (scheme 3) of the FLEXG model. This study integrated the objective functions of satellite-derived SCA and gauged streamflow into one criterion for the FLEXG model calibration using a weight-based approach. Our results showed that calibrating the FLEXG model based on solely satellite SCA data (from MODIS) produced an accurate simulation of SCA but poor simulation of streamflow. In contrast, calibrating the FLEXG model based on the measured streamflow data resulted in minimum error for streamflow simulation but high error for SCA simulation. The promising results were achieved for glacio-hydrological simulation with acceptable accuracy for simulation of both streamflow and SCA, when both streamflow and SCA data were used for calibration of FLEXG. Therefore, multi-variable calibration in a glacierized basin could provide more realistic hydrological modeling in terms of multiple glacio-hydrological variables.
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