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  • 1.
    Ali, Fadi
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Urban classification by pixel and object-based approaches for very high resolution imagery2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Recently, there is a tremendous amount of high resolution imagery that wasn’t available years ago, mainly because of the advancement of the technology in capturing such images. Most of the very high resolution (VHR) imagery comes in three bands only the red, green and blue (RGB), whereas, the importance of using such imagery in remote sensing studies has been only considered lately, despite that, there are no enough studies examining the usefulness of these imagery in urban applications. This research proposes a method to investigate high resolution imagery to analyse an urban area using UAV imagery for land use and land cover classification. Remote sensing imagery comes in various characteristics and format from different sources, most commonly from satellite and airborne platforms. Recently, unmanned aerial vehicles (UAVs) have become a very good potential source to collect geographic data with new unique properties, most important asset is the VHR of spatiotemporal data structure. UAV systems are as a promising technology that will advance not only remote sensing but GIScience as well. UAVs imagery has been gaining popularity in the last decade for various remote sensing and GIS applications in general, and particularly in image analysis and classification. One of the concerns of UAV imagery is finding an optimal approach to classify UAV imagery which is usually hard to define, because many variables are involved in the process such as the properties of the image source and purpose of the classification. The main objective of this research is evaluating land use / land cover (LULC) classification for urban areas, whereas the data of the study area consists of VHR imagery of RGB bands collected by a basic, off-shelf and simple UAV. LULC classification was conducted by pixel and object-based approaches, where supervised algorithms were used for both approaches to classify the image. In pixel-based image analysis, three different algorithms were used to create a final classified map, where one algorithm was used in the object-based image analysis. The study also tested the effectiveness of object-based approach instead of pixel-based in order to minimize the difficulty in classifying mixed pixels in VHR imagery, while identifying all possible classes in the scene and maintain the high accuracy. Both approaches were applied to a UAV image with three spectral bands (red, green and blue), in addition to a DEM layer that was added later to the image as ancillary data. Previous studies of comparing pixel-based and object-based classification approaches claims that object-based had produced better results of classes for VHR imagery. Meanwhile several trade-offs are being made when selecting a classification approach that varies from different perspectives and factors such as time cost, trial and error, and subjectivity.

          Classification based on pixels was approached in this study through supervised learning algorithms, where the classification process included all necessary steps such as selecting representative training samples and creating a spectral signature file. The process in object-based classification included segmenting the UAV’s imagery and creating class rules by using feature extraction. In addition, the incorporation of hue, saturation and intensity (IHS) colour domain and Principle Component Analysis (PCA) layers were tested to evaluate the ability of such method to produce better results of classes for simple UAVs imagery. These UAVs are usually equipped with only RGB colour sensors, where combining more derived colour bands such as IHS has been proven useful in prior studies for object-based image analysis (OBIA) of UAV’s imagery, however, incorporating the IHS domain and PCA layers in this research did not provide much better classes. For the pixel-based classification approach, it was found that Maximum Likelihood algorithm performs better for VHR of UAV imagery than the other two algorithms, the Minimum Distance and Mahalanobis Distance. The difference in the overall accuracy for all algorithms in the pixel-based approach was obvious, where the values for Maximum Likelihood, Minimum Distance and Mahalanobis Distance were respectively as 86%, 80% and 76%. The Average Precision (AP) measure was calculated to compare between the pixel and object-based approaches, the result was higher in the object-based approach when applied for the buildings class, the AP measure for object-based classification was 0.9621 and 0.9152 for pixel-based classification. The results revealed that pixel-based classification is still effective and can be applicable for UAV imagery, however, the object-based classification that was done by the Nearest Neighbour algorithm has produced more appealing classes with higher accuracy. Also, it was concluded that OBIA has more power for extracting geographic information and easier integration within the GIS, whereas the result of this research is estimated to be applicable for classifying UAV’s imagery used for LULC applications.

  • 2.
    Bekele, Yared
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    GIS Based Factor Identification for the Change in Occurrence of Genista pilosa: a Case Study in Southern Sweden2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study has the objective of identifying the possible environmental constraints that has role for the continuous loss of heathland plant Genista pilosa. The study has assessed different environmental settings where the plant occurs by way of overlaying analysis based on multiple spatial data sets. Thereafter empirical change detection analyses on the land use of the study area have been performed on the GIS environment by combining temporal based remotely sensed spatial data. The result was then analyzed using land use dynamicity model and the rates of change on each land use type are identified. Expansion of human activity, especially the spreading of agricultural land and urbanization, is found to be the most determinant factor for the dramatic loss of the plant. Finally serious attention for the protection of the plant is recommended by mentioning the possible problem that would occur due to a loss of biodiversity.

  • 3.
    Borghero, Cecilia
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Feasibility study of dam deformation monitoring in northern Sweden using Sentinel1 SAR interferometry2018Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Dams are man-made structures that in order to keep functioning and to be considered structurally healthy need constant monitoring. Assessing the deformation of dams can be time consuming and economically costly.

    Recently, the technique of Interferometric Synthetic Aperture Radar (InSAR) has proved its potential to measure ground and structural deformation. This geodetic method represents a cost-effective way to monitor millimetre-level displacements and can be used as supplemental analysis to detect movements in the structure and its surroundings.

    The objective of this work is to assess the practicality of the method through the analysis of the surface deformation of the Ajaure dam located in northern Sweden, in the period 2014-2017, using the freely available Sentinel-1A images. The scenes, 51 in ascending and 47 in descending mode, were processed exploiting the Persistent Scatterer (PS) technique and deformation trends, and time series were produced.

    Built in the 60’s, the Ajaure embankment dam is considered as high consequence, meaning that a failure would cause socio-economic damages to the communities involved and, for this reason, the dam needs constant attention. So far, a program of automatic measurements in situ has been collecting data, which have been used partly to compare with InSAR results.

    Results of the multi temporal analysis of the limited PS points on/around the dam show that the dam has been subsiding more intensely toward the centre, where maximum values are of approximately 5 ± 1.25 mm/year (descending) and 2 ± 1.27 mm/year (ascending) at different locations (separated of approximately 70 m). Outermost points instead show values within -0.7 and 0.9 mm/year, describing a stable behaviour. The decomposition of the rate has furthermore revealed that the crest in the observation period has laterally moved toward the reservoir.

    It has been observed that the operation of loading and unloading the reservoir influence the dam behaviour. The movements recorded by the PS points on the dam also correlate with the air temperature (i.e. seasonal cycle).

    The research revealed that the snow cover and the vegetation could have interfered with the signal, that resulted in a relative low correlation. Therefore, the number of PS points on and around the dam is limited, and comparison with the geodetic data is only based on a few points. The comparison shows general agreement, showing the capacities of the InSAR method.

    The study constitutes a starting point for further improvements, for example observation in longer period when more Sentinel1 images of the study area are collected. Installation of corner reflectors at the dam site and/or by use of high resolution SAR data is also suggested.

  • 4.
    Brandt, S. Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Lim, Nancy J.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Visualising DEM-related flood-map uncertainties using a disparity-distance equation algorithm2016In: IAHS-AISH Proceedings and Reports / [ed] A. H. Schumann, G. Blöschl, A. Castellarin, J. Dietrich, S. Grimaldi, U. Haberlandt, A. Montanari, D. Rosbjerg, A. Viglione, and S. Vorogushyn, Göttingen: Copernicus Publications on behalf of International Association of Hydrological Sciences (IAHS) , 2016, Vol. 373, p. 153-159Conference paper (Refereed)
    Abstract [en]

    The apparent absoluteness of information presented by crisp-delineated flood boundaries can lead tomisconceptions among planners about the inherent uncertainties associated in generated flood maps. Even mapsbased on hydraulic modelling using the highest-resolution digital elevation models (DEMs), and calibrated withthe most optimal Manning’s roughness (n) coefficients, are susceptible to errors when compared to actual floodboundaries, specifically in flat areas. Therefore, the inaccuracies in inundation extents, brought about by thecharacteristics of the slope perpendicular to the flow direction of the river, have to be accounted for. Instead ofusing the typical Monte Carlo simulation and probabilistic methods for uncertainty quantification, an empiricalbaseddisparity-distance equation that considers the effects of both the DEM resolution and slope was used tocreate prediction-uncertainty zones around the resulting inundation extents of a one-dimensional (1-D) hydraulicmodel. The equation was originally derived for the Eskilstuna River where flood maps, based on DEM dataof different resolutions, were evaluated for the slope-disparity relationship. To assess whether the equation isapplicable to another river with different characteristics, modelled inundation extents from the Testebo Riverwere utilised and tested with the equation. By using the cross-sectional locations, water surface elevations, andDEM, uncertainty zones around the original inundation boundary line can be produced for different confidences.The results show that (1) the proposed method is useful both for estimating and directly visualising modelinaccuracies caused by the combined effects of slope and DEM resolution, and (2) the DEM-related uncertaintiesalone do not account for the total inaccuracy of the derived flood map. Decision-makers can apply it to alreadyexisting flood maps, thereby recapitulating and re-analysing the inundation boundaries and the areas that areuncertain. Hence, more comprehensive flood information can be provided when determining locations whereextra precautions are needed. Yet, when applied, users must also be aware that there are other factors that caninfluence the extent of the delineated flood boundary.

  • 5.
    Brandt, S. Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Lim, Nancy Joy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Importance of river bank and floodplain slopes on the accuracy of flood inundation mapping2012In: River Flow 2012: Volume 2 / [ed] Rafael Murillo Muñoz, Leiden, The Netherlands: CRC Press / Balkema (Taylor & Francis) , 2012, p. 1015-1020Conference paper (Refereed)
    Abstract [en]

    Effective flood assessment and management depend on accurate models of flood events, which in turn are strongly affected by the quality of digital elevation models (DEMs). In this study, HEC-RAS was used to route one specificwater discharge through the main channel of the Eskilstuna River, Sweden. DEMs with various resolutions and accuracies were used to model the inundation. The results showed a strong positive relationship between the quality of theDEMand the extent of the inundation. However, evenDEMswith the highest resolution produced inaccuracies. In another case study, the Testebo River, the model settings could be calibrated, thanks to a surveyed old inundation event. However, even with the calibration efforts, the resulting inundation extents showed varying degrees of deviation from the surveyed flood boundaries. Therefore, it becomes clear that not only does the resolution of the DEM impact the quality of the results; also, the floodplain slope perpendicular to the river flow will impact the modelling accuracy. Flatter areas exhibited the greatest predictive uncertainties regardless of the DEM’s resolution. For perfectly flat areas, uncertainty becomes infinite.

  • 6.
    Cooke, Sarah
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Using remote sensing and aerial archaeology to detect pit house features in Worldview-2 satellite imagery.: A case study for the Bridge River archaeological pit house village in south-central British Columbia, Canada.2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    It is well known that archaeological sites are important sources for understanding past human activity. However, those sites yet to be identified and further investigated are under a great risk of being lost or damaged before their archaeological significance is fully recognized. The aim of this research was to analyze the potential use of remote sensing and aerial archaeology techniques integrated within a geographic information system (GIS) for the purpose of remotely studying pit house archaeology. As pit house archaeological sites in North America have rarely been studied with a focus in remote sensing, this study intended to identify these features by processing very high resolution satellite imagery and assessing how accurately the identified features could be automatically mapped with the use of a GIS. A Worldview-2 satellite image of the Bridge River pit house village in Lillooet, south-central British Columbia, was processed within ArcGIS 10.1 (ESRI), ERDAS Imagine 2011 (Intergraph) and eCognition Developer 8 (Trimble) to identify spatial and spectral queues representing the pit house features. The study outlined three different feature extraction methods (GIS-based, pixel-based and object-based) and evaluated which method presented the best results. Though all three methods produced similar results, the potential for performing object-based feature extraction for research in aerial archaeology proved to be more advantageous than the other two extraction methods tested.

  • 7.
    Grift, Jeroen
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Forest Change Mapping in Southwestern Madagascar using Landsat-5 TM Imagery, 1990 –20102016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main goal of this study was to map and measure forest change in the southwestern part of Madagascar near the city of Toliara in the period 1990-2010. Recent studies show that forest change in Madagascar on a regional scale does not only deal with forest loss, but also with forest growth However, it is unclear how the study area is dealing with these patterns. In order to select the right classification method, pixel-based classification was compared with object-based classification. The results of this study shows that the object-based classification method was the most suitable method for this landscape. However, the pixel-based approaches also resulted in accurate results. Furthermore, the study shows that in the period 1990–2010, 42% of the forest cover disappeared and was converted into bare soil and savannahs. Next to the change in forest, stable forest regions were fragmented. This has negative effects on the amount of suitable habitats for Malagasy fauna. Finally, the scaling structure in landscape patches was investigated. The study shows that the patch size distribution has long-tail properties and that these properties do not change in periods of deforestation.

  • 8.
    Harrie, Lars
    et al.
    Lund University.
    Larsson, Karin
    Lund University.
    Tenenbaum, David
    Lund University.
    Horemuz, Milan
    Royal Institute of Technology (KTH).
    Ridefelt, Hanna
    National mapping and land registration authority, Gävle, Sweden.
    Lysell, Gunnar
    National mapping and land registration authority, Gävle, Sweden.
    Brandt, S. Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Sahlin, Eva A.U.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Adelsköld, Göran
    Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Högström, Mats
    Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Lagerstedt, Jakob
    Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Some strategic national initiatives for the Swedish education in the geodata field2014In: Connecting a Digital Europe through Location and Place: Selected best short papers and posters of the AGILE 2014 Conference, 3‐6 June 2014, Castellón, Spain / [ed] Joaquin Huerta, Sven Schade, Carlos Granell, AGILE Digital Editions , 2014Conference paper (Refereed)
    Abstract [en]

    This paper describes national cooperation in Sweden launched by its universities and authorities, aimed at improving geodata education. These initiatives have been focused upon providing common access to geodata, the production of teaching materials in Swedish and organizing annual meetings for teachers. We argue that this type of cooperation is vital to providing high quality education for a poorly recognized subject in a country with a relatively small population.

  • 9.
    Kordi, Maryam
    et al.
    National University of Ireland, National Centre for Geocomputation.
    Brandt, Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Effects of increasing fuzziness on analytic hierarchy process for spatial multicriteria decision analysis2012In: Computers, Environment and Urban Systems, ISSN 0198-9715, E-ISSN 1873-7587, Vol. 36, no 1, p. 43-53Article in journal (Refereed)
    Abstract [en]

    Multicriteria decision analysis (MCDA) involves techniques which relatively recently have received great increase in interest for their capabilities of solving spatial decision problems. One of the most frequently used techniques of MCDA is Analytic Hierarchy Process (AHP). In the AHP, decision-makers make pairwise comparisons between different criteria to obtain values of their relative importance. The AHP initially only dealt with crisp numbers or exact values in the pairwise comparisons, but later it has been modified and adapted to also consider fuzzy values. It is necessary to empirically validate the ability of the fuzzified AHP for solving spatial problems. Further, the effects of different levels of fuzzification on the method have to be studied. In the context of a hypothetical GIS-based decision-making problem of locating a dam in Costa Rica using real-world data, this paper illustrates and compares the effects of increasing levels of uncertainty exemplified through different levels of fuzzification of the AHP. Practical comparison of the methods in this work, in accordance with the theoretical research, revealed that by increasing the level of uncertainty or fuzziness in the fuzzy AHP, differences between results of the conventional and fuzzy AHPs become more significant. These differences in the results of the methods may affect the final decisions in decision-making processes. This study concludes that the AHP is sensitive to the level of fuzzification and decision-makers should be aware of this sensitivity while using the fuzzy AHP. Furthermore, the methodology described may serve as a guideline on how to perform a sensitivity analysis in spatial MCDA. Depending on the character of criteria weights, i.e. the degree of fuzzification, and its impact on the results of a selected decision rule (e.g. AHP), the results from a fuzzy analysis may be used to produce sensitivity estimates for crisp AHP MCDA methods.

  • 10.
    Lee, Steven
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Detecting Wetland Change through Supervised Classification of Landsat Satellite Imagery within the Tunkwa Watershed of British Columbia, Canada2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wetlands are considered to be one of the most valuable natural occurring forms of land cover in the world. Hydrologic regulation, carbon sequestration, and habitat provision for a wide assortment of flora and fauna are just a few of the benefits associated with wetlands. The implementation of satellite remote sensing has been demonstrated to be a reliable approach to monitoring wetlands over time. Unfortunately, a national wetland inventory does not exist for Canada at this time. This study employs a supervised classification method of Landsat satellite imagery between 1976 and 2008 within the Tunkwa watershed, southwest of Kamloops, British Columbia, Canada. Images from 2005 and 2008 were repaired using a gap-filling technique due to do the failure of the scan-line corrector on the Landsat 7 satellite in 2003. Percentage pixel counts for wetlands were compared, and a diminishing trend was identified; approximately 4.8% of wetland coverage loss was recognized. The influence of the expansion of Highland Valley Copper and the forestry industry in the area may be the leading causes of wetland desiccation. This study expresses the feasibility of wetland monitoring using remote sensing and emphasizes the need for future work to compile a Canadian wetland inventory.

  • 11.
    Lim, Nancy J.
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Brandt, S. Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Are Feature Agreement Statistics Alone Sufficient to Validate Modelled Flood Extent Quality?: A Study on Three Swedish Rivers Using Different Digital Elevation Model Resolutions2019In: Mathematical problems in engineering (Print), ISSN 1024-123X, E-ISSN 1563-5147, Vol. 2019, article id 9816098Article in journal (Refereed)
    Abstract [en]

    Hydraulic modelling is now, at increasing rates, used all over the world to provide flood risk maps for spatial planning, flood insurance, etc. This puts heavy pressure on the modellers and analysts to not only produce the maps but also information on the accuracy and uncertainty of these maps. A common means to deliver this is through performance measures or feature statistics. These look at the global agreement between the modelled flood area and the reference flood that is used. Previous studies have shown that the feature agreement statistics do not differ much between models that have been based on digital elevation models (DEMs) of different resolutions, which is somewhat surprising since most researchers agree that high-resolution DEMs are to be preferred over poor resolution DEMs. Hence, the aim of this study was to look into how and under which conditions the different feature agreement statistics differ, in order to see when the full potential of high-resolution DEMs can be utilised. The results show that although poor resolution DEMs might produce high feature agreement scores (around F > 0.80), they may fail to provide good flood extent estimations locally, particularly when the terrain is flat. Therefore, when high-resolution DEMs (1 to 5 m) are used, it is important to carefully calibrate the models by the use of the roughness parameter. Furthermore, to get better estimates on the accuracy of the models, other performance measures such as distance disparities should be considered.

  • 12.
    Myagmartseren, Purevtseren
    et al.
    Department of Geography, School of Arts and Science, National University of Mongolia, Ulaanbaatar, Mongolia.
    Buyandelger, Myagmarsuren
    Land Administration Department of Capital City, Ulaanbaatar, Mongolia.
    Brandt, S. Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Implications of a Spatial Multicriteria Decision Analysis for Urban Development in Ulaanbaatar, Mongolia2017In: Mathematical problems in engineering (Print), ISSN 1024-123X, E-ISSN 1563-5147, Vol. 2017, article id 2819795Article in journal (Refereed)
    Abstract [en]

    New technology has provided new tools for effective spatial planning. Through the example of locating suitable sites for urbandevelopment in Ulaanbaatar, this paper illustrates how multicriteria decision analysis and geographical information systems canbe used for more effective urban planning. Several constraint and factor criteria were identified, transformed into map layers,and weighted together using the analytic hierarchy process. Besides localization results, this study shows the effect of using poorelevation data and how a sensitivity analysis can be applied to yield further information, spot weighting weaknesses, and assess thequality of the criteria.

  • 13.
    Reshetyuk, Yuriy
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Terrestrial laser scanning: Error sources, self-calibration and direct georeferencing2009Book (Refereed)
    Abstract [en]

    During the last decade, terrestrial laser scanning (TLS) has appeared as a new surveying technique. Its proper use requires good knowledge of the error sources, comprehensive description of which is currently lacking. Especially important are systematic instrumental errors, which are determined during calibration. Recently, the method of self-calibration used in photogrammetry has been shown to be efficient for laser scanners. Another important task in TLS is georeferencing – transformation of the point clouds into a specific coordinate system. This book provides a systematic description of the error sources in TLS surveys conducted with direct georeferencing. Further, a new, unified approach for laser scanner self-calibration is described, and the results of calibration of three scanners are reported. Finally, a prototype combined TLS survey system is presented, which employs GPS for direct georeferencing of the point clouds, and can be used for accurate surveys of built environments. The book should be useful to students and researchers in Engineering Surveying as well as surveyors in public and private sector.

  • 14.
    Sahlin, Eva A.U.
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Glasser, Neil F.
    Institute of Geography and Earth Sciences, Aberystwyth University, Wales.
    The Geomorphological Map of Wales and its use in Geoconservation Assessment (poster)2011Conference paper (Other academic)
    Abstract [en]

    A geomorphological map is probably the most comprehensive way of illustrating the landform distribution, surface form, material, age, and the processes responsible for the landscape look. As such geomorphological maps are invaluable in the fields of geoconservation assessment, evaluation and management. It is therefore an oddity, as well as an inconvenience, that there is no systematic landform inventory or mapping of the geomorphology that is comparable to the surveys undertaken for geology or soils in the UK. For that purpose the project of “Developing a Geomorphological Map of Wales” was initiated by the Countryside Council for Wales (CCW) as part of a PhD project investigating the Quaternary glaciations of Wales.

    To develop a mapping methodology suitable for the Welsh landscape, three contrasting areas were selected to provide a wide range of geomorphological features. Aerial photography, satellite imagery, digital elevation models, and field investigations of landform/sediment associations, formed the foundation for landform interpretation, which were compiled in a GIS.

    Geomorphological maps of Cadair Idris, and the Central and North Cambrian Mountains were produced, scale 1:10 000 – 1:25 000. The maps form an extensive inventory of the geomorphological geodiversity, and were used for providing data to palaeoglaciological reconstructions and making geoconservation recommendations to the CCW. The recommended sites are of regional interest; their rareness, distinct morphology, interesting research and educational value makes them worthy of RIGS (Regional Important Geodiversity Sites) protection.

    A Geomorphological Map of Wales has the potential for wider practical, scientific and educational benefits, such as for governmental bodies, local authority planners, tourism, researchers, teachers, landowners and land managers. Without a full account of all the geomorphological components of a landscape, there can be no full understanding of the landscape history or the various landforming processes. Important geodiversity sites may be overlooked, badly managed or lost before their full potential are realised.

  • 15.
    Sahlin, Eva A.U.
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Glasser, Neil F.
    Institute of Geography and Earth Sciences, Aberystwyth University, Wales.
    Hambrey, Michael, J.
    Institute of Geography and Earth Sciences, Aberystwyth University, Wales.
    Jansson, Krister, N.
    Institutionen för naturgeografi och kvartärgeologi, Stockholms universitet.
    Connectivity analyses of valley patterns reveal Devensian glacial drainage activity in Mid-Wales (poster)2009Conference paper (Other academic)
    Abstract [en]

    Coastal valleys in the west part of Mid-Wales, such as the Mawddach, Dysynni, Tal-y-llyn and Dyfi, are believed to have acted as corridors for ice which drained the Welsh Ice Cap during the Devensian. Connectivity analyses of valley patterns from detailed digital elevation models, and interpretation of satellite images and aerial photographs show the existence of large variations in the amount of glacial modification between these valleys. Although all the valleys are glacially over-deepened along Silurian fault lines, only the Dyfi basin exhibits a dendritic pattern, with V-shaped cross profiles and valley spurs typical of valleys formed by fluvial processes.

    The connectivity analyses show that the Dyfi basin exhibits a purely dendritic pattern with little glacial modification of the preglacial fluvial valley pattern in form of valley breaching. It is proposed here that the general river valley morphology of the Dyfi basin is of a pre-Late Devensian age. This suggests a complex glacial drainage history, where cold-based ice was not only confined to the interior uplands, but also covered low-altitude areas previously believed to be a major drainage conduit for the Welsh Ice Cap. This indicates that Late Devensian glacial erosion was not as intense as previously believed and larger areas might have been overlain by cold-based ice.

  • 16.
    Sahlin, Eva A.U.
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för samhällsbyggnad.
    Glasser, Neil F.
    Institute of Geography and Earth Sciences, Aberystwyth University, Wales.
    Jansson, Krister N.
    Institutionen för naturgeografi och kvartärgeologi, Stockholms Universitet.
    Hambrey, Michael J.
    Institute of Geography and Earth Sciences, Aberystwyth University, Wales.
    Evidence for cold-based ice at low altitudes: Preservation of a preglacial fluvial valley system in the Dyfi basin, Wales (poster)2009Conference paper (Other academic)
    Abstract [en]

    Coastal valleys in the west part of mid-Wales, such as the Mawddach, Dysynni, Tal-y-llyn and Dyfi, are believed to have acted as corridors for ice which drained the Welsh Ice Cap during the Devensian. Analysis of detailed digital elevation models and interpretation of satellite images and aerial photographs show the existence of large variations in the amount of glacial modification between these valleys. Although all the valleys are glacially over-deepened along Silurian fault lines, only the Dyfi basin exhibits a dendritic pattern, with V-shaped cross profiles and valley spurs typical of valleys formed by fluvial processes. Connectivity analysis of the Dyfi basin shows that it exhibits a nearly dendritic pattern with connectivity α and β values of 0.74 and 1.01 respectively, with little glacial modification of the preglacial fluvial valley pattern in the form of valley breaching. It is proposed that the general river valley morphology of the Dyfi basin is of a pre-Late Devensian age. Several examples have been identified of glacial meltwater incision into a well-developed pre-existing river valley system, causing river capture across watersheds. The degree of preservation of the pre-glacial fluvial valley system within the Dyfi basin indicates limited modification by glacial processes, despite the area being subjected to Late Devensian glacier activity. It is possible that major parts of the basin were covered by cold-based or slow-moving ice close to or under a migrating ice divide, with the major ice drainage occurring along the weaker zone of the Pennal Fault, causing minor adjustments to the surrounding interfluves and uplands.

  • 17.
    Wu, Jie
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Zhou, Lina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    GIS-Based Multi-Criteria Analysis for Hostital Selection in Haidian District of Beijing2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    China has the largest population and the fastest growing economy in the world. The general public's demand for health is rising promptly with the improvement of the living standard. However, the limited and unbalanced medical resource have caused the prominent problem of the society, even in the capital city of Beijing, the new hospital constructions with rational allocation is iminent and significant. Along with the technology development and Internet popularization, GIS approaches and related products has been widely used in the people's daily life. The main focus of this paper is to select a site for building a new hospital in Haidian District of Beijing using GIS-based Multi-Criteria Analysis (MCA). With Analytical Hieraichy Process(AHP) and Rank Order Method (ROM) for the weight setting on factor criteria, necessity tests and sensitivity tests are applied to check which criteria are really necessary and how the results are sensitive to their weight change. The optimal site located in Wenquan Town (E: 116.182, N:40.039) is screened from several candidate sites usin Google Earth maps, which makes the ultimate result more convincing and practical. It can be concluded that GIS-based MCA with necessity and sensitivity tests proposes a novel and useful reference to other site selection decision makers, and also provides constructive tools for the public asministration to set up efficent databases for decision makers to carry out spatial analyses. To make it more maneuverable and practical, a further research on th improvement of this method will have a promising future. 

  • 18.
    Zutautas, Vaidutis
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Charcoal Kiln Detection from LiDAR-derived Digital Elevation Models Combining Morphometric Classification and Image Processing Techniques2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This paper describes a unique method for the semi-automatic detection of historic charcoal production sites in LiDAR-derived digital elevation models. Intensified iron production in the early 17th century has remarkably influenced ways of how the land in Sweden was managed. Today, the abundance of charcoal kilns embedded in the landscape survives as cultural heritage monuments that testify about the scale forest management for charcoal production has contributed to the uprising iron manufacturing industry. An arbitrary selected study area (54 km2) south west of Gävle city served as an ideal testing ground, which is known to consist of already registered as well as unsurveyed charcoal kiln sites. The proposed approach encompasses combined morphometric classification methods being subjected to analytical image processing, where an image that represents refined terrain morphology was segmented and further followed by Hough Circle transfer function applied in seeking to detect circular shapes that represent charcoal kilns. Sites that have been identified manually and using the proposed method were only verified within an additionally established smaller validation area (6 km2). The resulting outcome accuracy was measured by calculating harmonic mean of precision and recall (F1-Score). Along with indication of previously undiscovered site locations, the proposed method showed relatively high score in recognising already registered sites after post-processing filtering. In spite of required continual fine-tuning, the described method can considerably facilitate mapping and overall management of cultural resources.

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