44 research outputs found
Tools for Semi-automated Landform Classification: A Comparison in the Basilicata Region (Southern Italy)
Recent advances in spatial methods of digital elevation model
(DEMs) analysis have addressed many research topics on the assessment of
morphometric parameters of the landscape. Development of computer algorithms for calculating the geomorphometric properties of the Earthâs surface has
allowed for expanding of some methods in the semi-automatic recognition and
classification of landscape features. In such a way, several papers have been
produced, documenting the applicability of the landform classification based on
map algebra. The Topographic Position Index (TPI) is one of the most widely
used parameters for semi-automated landform classification using GIS software.
The aim was to apply the TPI classes for landform classification in the Basilicata
Region (Southern Italy). The Basilicata Region is characterized by an extremely
heterogeneous landscape and geological features. The automated landform
extraction, starting from two different resolution DEMs at 20 and 5 m-grids, has
been carried out by using three different GIS software: Arcview, Arcmap, and
SAGA. Comparison of the landform maps resulting from each software at a
different scale has been realized, furnishing at the end the best landform map and
consequently a discussion over which is the best software implementation of the
TPI method
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F.J. Turnerâs âfrontier thesisâ: the ruse of American âcharacter'
American society was transformed by the expansion of capital Westward and the explosion in opportunities that ensued for land grabbing and agricultural and industrial investment. In Turnerâs (1961) frontier thesis this was portrayed as resulting in the emergence of âthe new manâ i.e. the fulfilment of American character. The frontier thesis is a neo-Darwinian contribution. It posits exceptionalism and transcendence as the keys to American character. The gene pool of the Americans, thriving in a new geographical and social environment, is depicted as achieving a higher level of development than the stratified societies of Old Europe. What the thesis ignores is the importance of orthodox Eurocentric strategies of colonization and land appropriation. Turner portrays pioneer/settler society as a heroic departure, but in many ways, it is a continuation of European precedents. Analogously, the proposition that the push West crystallized American character obscures the role of personality, especially in urban-industrial settings, in establishing the parameters of American life. Turner conceived of character as emerging from a struggle with the spatial frontier. But the struggles of personality with the social frontier of repression and establishment values is no less significant. The paper examines the tensions between character and personality by using some ideas developed by Carl Schmitt on the significance of âthe opportunityâ in competitive advantage. The importance of the opportunity and personality in developing the American way of life are examined by the vaudeville and celebrity traditions. The exploitation of contingency for personal advantage, the use of melodrama to engineer social impact, the social validation of forthright behaviour are examined in the context of the careers of the film actress Mae West and the comedian Bob Hope
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Surface metrics: an alternative to patch metrics for the quantification of landscape structure
Modern landscape ecology is based on the patch mosaic paradigm, in which landscapes are conceptualized and analyzed as mosaics of discrete patches. While this model has been widely successful, there are many situations where it is more meaningful to model landscape structure based on continuous rather than discrete spatial heterogeneity. The growing field of surface metrology offers a variety of surface metrics for quantifying landscape gradients, yet these metrics are largely unknown and/or unused by landscape ecologists. In this paper, we describe a suite of surface metrics with potential for landscape ecological application. We assessed the redundancy among metrics and sought to find groups of similarly behaved metrics by examining metric performance across 264 sample landscapes in western Turkey. For comparative purposes and to evaluate the robustness of the observed patterns, we examined 16 different patch mosaic models and 18 different landscape gradient models of landscape structure. Surface metrics were highly redundant, but less so than patch metrics, and consistently aggregated into four cohesive clusters of similarly behaved metrics representing surface roughness, shape of the surface height distribution, and angular and radial surface texture. While the surface roughness metrics have strong analogs among the patch metrics, the other surface components are largely unique to landscape gradients. We contend that the surface properties we identified are nearly universal and have potential to offer new insights into landscape patternâprocess relationships
The Relationship of Urban Expansion, Landscape Patterns and Ecological Processes in Denizli, Turkey
Perforation, dissection, fragmentation, shrinkage and attrition in ecosystems take place due to urbanization. In this study, where and when temporal and spatial heterogeneity occurs is tried to be explained by taking human intervention in landscape pattern and processes in and around the city of Denizli into account and how this heterogeneity affects habitat conditions within the scope of landscape ecology. Landscape pattern metrics were estimated in order to reveal the change in habitats and present the properties of the landscape. 30 pattern indicators on class and pattern levels, which are important to show humanâenvironment interaction, were analyzed in order to indicate the features of the landscape such as area, side, shape and dispersion. To this end, LANDSAT TM/7âETM/8-OLI satellite images of 1987 and 2013 were classified for laying the foundations of the analysis. Analyses showed that between 1987 and 2013, complicated shape features, increase in edge habitats, de-growth in core areas and eventually fragmentation in landscape have been dominant. Heterogenic structure in landscape has increased. This points not to the self-functioning of the landscape, but to the domination of human intervention over the landscape. Particularly, due to urban growth and sprawl, fragmentation, isolation and habitat loss in croplands have increased. This study sets forth the usefulness of remote sensing, GIS and landscape metrics in understanding how urban dynamics and ecosystems change in developing urban politics. © 2018, Indian Society of Remote Sensing
Proposing an agricultural belt to protect a cityâs semi-rural characteristics: The example of Bartın, Turkey
Urban sprawl, a type of urban expansion, is perceived as a global problem due to changes in land conversions and landscape patterns. Farms, forests and shores have been converted into urban areas; this transformation affects energy flow, biochemical cycles and climatic conditions. To follow and evaluate the physical, social and ecological results of urban sprawl, we identified and measured temporal changes in land use and land cover. This is especially important for urban planning policies. In this study, temporal change is identified in the city of Bartın using remote sensing and landscape metrics. An analysis of land cover and land transformation was done with LANDSAT5 TM/ETM satellite images from 1985 and 2015. These images were used to identify agricultural areas as land that has most commonly undergone drastic changes. Bartın is a small semi-rural city that has undergone significant changes. Among the most important reasons for these changes were uncontrolled urban sprawl due to political and administrative decisions that lacked long-term planning and a comprehensive city plan. This study examined the risk factors for loss of semi-rural characteristics using the example of Bartın city. To protect semi-rural city characteristics and control urban sprawl, we propose an agricultural belt based on spatial suitability and an evaluation of landscape metrics. © 2018, © 2018 Landscape Research Group Ltd
A decision support system improves the interpretation of myocardial perfusion imaging
PURPOSE: The aim of this study was to investigate the influence of a computer-based decision support system (DSS) on performance and inter-observer variability of interpretations regarding ischaemia and infarction in myocardial perfusion scintigraphy (MPS). METHODS: Seven physicians independently interpreted 97 MPS studies, first without and then with the advice of a DSS. Four physicians had long experience and three had limited experience in the interpretation of MPS. Each study was interpreted regarding myocardial ischaemia and infarction in five myocardial regions. The patients had undergone a gated MPS using a 2-day stress/gated rest (99m)Tc sestamibi protocol. The gold standard used was the interpretations made by one experienced nuclear medicine specialist on the basis of all available clinical and image information. RESULTS: The sensitivity for ischaemia of the seven readers increased from 81% without the DSS to 86% with the DSS (p = 0.01). The increase in sensitivity was higher for the three inexperienced physicians (9%) than for the four experienced physicians (2%). There was no significant change in specificity between the interpretations. The interpretations of ischaemia made with the advice of the DSS showed less inter-observer variability than those made without advice. CONCLUSION: This study shows that a DSS can improve performance and reduces the inter-observer variability of interpretations in myocardial perfusion imaging. Both experienced and, especially, inexperienced physicians can improve their interpretation with the advice from such a system