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Geographical Data (geographical + data)
Selected AbstractsGeographically Weighted Discriminant AnalysisGEOGRAPHICAL ANALYSIS, Issue 4 2007Chris Brunsdon In this article, we propose a novel analysis technique for geographical data, Geographically Weighted Discriminant Analysis. This approach adapts the method of Geographically Weighted Regression (GWR), allowing the modeling and prediction of categorical response variables. As with GWR, the relationship between predictor and response variables may alter over space, and calibration is achieved using a moving kernel window approach. The methodology is outlined and is illustrated with an example analysis of voting patterns in the 2005 UK general election. The example shows that similar social conditions can lead to different voting outcomes in different parts of England and Wales. Also discussed are techniques for visualizing the results of the analysis and methods for choosing the extent of the moving kernel window. [source] Power of the Rank Adjacency Statistic to Detect Spatial Clustering in a Small Number of RegionsGEOGRAPHICAL ANALYSIS, Issue 1 2001John Paul Ekwaru The rank adjacency statistic D is a statistical method for assessing spatial autocorrelation or clustering of geographical data. It was originally proposed for summarizing the geographical patterns of cancer data in Scotland (IARC 1985). In this paper, we investigate the power of the rank adjacency statistic to detect spatial clustering when a small number of regions is involved. The investigations were carried out using Monte Carlo simulations, which involved generating patterned/clustered values and computing the power with which the D statistic would detect it. To investigate the effects of region shapes, structure of the regions, and definition of weights, simulations were carried out using two different region shapes, binary and nonhinary weights, and three different lattice structures. The results indicate that in the typical example of considering Canadian total mortality at the electoral district level, the D statistic had adequate power to detect general spatial autocorrelation in twenty-five or more regions. There was an inverse relationship between power and the level of connectedness of the regions, which depends on the weighting function, shape, and arrangement of the regions. The power of the D statistic was also found to compare favorably with that of Moran's I statistic. [source] Distribution pattern of endangered bird species in ChinaINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 4 2006Fumin LEI Abstract In this study, we determined six "hotspots" for avian biodiversity conservation in China. We analyzed the distribution patterns of 183 threatened bird species in China in conjunction with geographical data to produce a distribution map that shows the concentrations of threatened species. The six biodiversity hotspots are: the western Tianshan Mountains; the Qilian and Hengduan mountains; southern Anhui, southern Jiangsu, and the Zhejiang Hills; the Songliao Plain and the northern region of the North China Plain; the island of Taiwan; and the island of Hainan. Based on our analysis of a species,habitat matrix, species were determined to be distributed mainly in broadleaved forest, grassland and meadows, urban and agricultural areas, wetlands, and bush. Most species were commonly found to have a range of three to five different habitat types. Apart from the six biodiversity hotspots, six ecological clusters were determined. Protection strategies indicating different levels of habitat priority among the biodiversity hotspots were also recommended. [source] Regional Inequalities and Civil Conflict in Sub-Saharan Africa,INTERNATIONAL STUDIES QUARTERLY, Issue 2 2009Gudrun ØStby The case study literature is ripe with examples of a positive association between inequality and civil war, but systematic country-level studies have largely failed to find a significant relationship. One reason for this discrepancy may be that large-N studies tend to ignore spatial variations in group welfare within countries, although civil wars often take place within limited areas. We address this gap in the literature by applying GIS operations to Demographic and Health Surveys to construct new disaggregated data on welfare and socioeconomic inequalities between and within subnational regions in 22 countries in Sub-Saharan Africa. These measures are coupled with geographical data on the location of conflict zones for the period 1986,2004. We find that conflict onsets are more likely in regions with (1) low levels of education; (2) strong relative deprivation regarding household assets; (3) strong intraregional inequalities; and (4) combined presence of natural resources and relative deprivation. [source] Biogeography of Plagiochila (Hepaticae): natural species groups span several floristic kingdomsJOURNAL OF BIOGEOGRAPHY, Issue 7 2003Henk Groth Abstract Aim This paper presents a synthesis of our recent results regarding the biogeography of Plagiochila using a molecular approach, and documents intercontinental ranges within this largest genus of the hepatics. Methods A maximum likelihood analysis of sixty-one nrITS sequences of Plagiochila was performed and the molecular topology obtained was compared with morphological, phytochemical and geographical data. Results Our molecular data set allowed the identification of eleven Plagiochila sections, the majority of which cover at least two floristic kingdoms. Seven sections have species in Europe (sect. Arrectae, Carringtoniae, Fuscoluteae, Glaucescentes, Plagiochila, Rutilantes, Vagae). Plagiochila species from Atlantic Europe are usually close to or conspecific with neotropical taxa, whereas species widespread in Europe are closely related to Asian ones and not to those in the Neotropics. Plagiochila sect. Arrectae represents a neotropical , Atlantic European clade. The section is not closely related , as has often been suggested , to the morphologically similar sect. Zonatae from Asia and western North America. Sequence data show that the African P. integerrima and the neotropical P. subplana are members of the Asian sect. Cucullatae (sect. Ciliatae, syn. nov.), which becomes pantropical in distribution. An ITS sequence of P. boryana from Uganda confirms the Afro-American range of the primarily neotropical sect. Hylacoetes. Similarities in sporophyte morphology between the sect. Cucullatae and sect. Hylacoetes are the result of parallel evolution. Main conclusions Our results indicate that intercontinental ranges at section and species level are common in Plagiochila. Carl's (1931) subdivision of Plagiochila into sections restricted to one floristic kingdom is outdated. Biogeographical patterns in Plagiochila are not dissimilar to those of other groups of bryophytes but elucidation of the geographical ranges of the taxa requires a molecular approach. Contrary to earlier belief, most Plagiochila species from Atlantic Europe do not have close relatives in Asia but are conspecific with or closely related to species from tropical America. [source] geophylobuilder 1.0: an arcgis extension for creating ,geophylogenies'MOLECULAR ECOLOGY RESOURCES, Issue 1 2008DAVID M. KIDD Abstract Evolution is inherently a spatiotemporal process; however, despite this, phylogenetic and geographical data and models remain largely isolated from one another. Geographical information systems provide a ready-made spatial modelling, analysis and dissemination environment within which phylogenetic models can be explicitly linked with their associated spatial data and subsequently integrated with other georeferenced data sets describing the biotic and abiotic environment. geophylobuilder 1.0 is an extension for the arcgis geographical information system that builds a ,geophylogenetic' data model from a phylogenetic tree and associated geographical data. Geophylogenetic database objects can subsequently be queried, spatially analysed and visualized in both 2D and 3D within a geographical information systems. [source] The global distribution of infant mortality: a subnational spatial viewPOPULATION, SPACE AND PLACE (PREVIOUSLY:-INT JOURNAL OF POPULATION GEOGRAPHY), Issue 3 2008Adam Storeygard Abstract We describe the compilation of a spatially explicit data-set detailing infant mortality rates in over 10,000 national and subnational units worldwide, benchmarked to the year 2000. Although their resolution is highly variable, subnational data are available for countries representing over 90% of the non-OECD population. Concentration of global infant deaths is higher than implied by national data alone. Assigning both national and subnational data to map grid cells so that they may be easily integrated with other geographical data, we generate infant mortality rates for environmental regions, including biomes and coastal zones, by continent. Rates for these regions also show striking refinements from the use of the higher resolution data. Possibilities and limitations for related work are discussed. Copyright © 2008 John Wiley & Sons, Ltd. [source] Aerial archaeology: a full digital workflow for aerial photographyARCHAEOLOGICAL PROSPECTION, Issue 4 2005Jürg Leckebusch Abstract Aerial archaeology is an established prospection method, but its systems and techniques have changed very little since its first applications. The advent of modern high-resolution digital cameras, with better image resolution and image depth than comparable analogue photography, offers the possibility of a full digital workflow. A new system is being developed to fulfil all the requirements of aerial archaeology. The images are stored on a PC, together with associated geographical data, including the location and orientation of the camera stations. A GIS displays the camera stations together with the flight path. Once the photographic record of a site is finished, the geographical co-ordinates of the target are calculated automatically, and combined with other data from a simple user interface to provide a complete primary data set during the flight. This allows the investigator to spend more time searching for sites during the flight, and simplifies the interpretation and analysis of the images in the office. This paper presents several new approaches to full integration of the systems involved. Copyright © 2005 John Wiley & Sons, Ltd. [source] Videogames, visuality and screens: reconstructing the Amazon in physical geographical knowledgeAREA, Issue 4 2009James N Ash In this article we attend to an emergent practice of visualising GIS data in physical geography using the graphics engine of a videogame, Crysis. We suggest these modes of image-making aid the possibility of imagining and disseminating complex geographical data differently by re-contextualising seemingly abstract mathematical information within a human horizon of embodied meaning. Furthermore we argue these ways of imagining are closely linked to the technology and phenomenology of screens which make the presentation of these images possible. We close by reflecting on the possibility that these technologies are shifting the grounds of vision and the geographical imagination of users. [source] Morphometric analysis of the Taxus wallichiana complex (Taxaceae) based on herbarium materialBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2007MICHAEL MÖLLER We used morphological and geographical data of 128 herbarium specimens of the Taxus wallichiana complex in eastern Asia to investigate their utilization in discriminating and identifying taxa included in the complex. One bud scale and 26 leaf characters were used to separate T. fuana, T. wallichiana var. wallichiana, T. wallichiana var. mairei, T. wallichiana var. chinensis and T. sumatrana by K-means clustering and dendrograms using Ward's distance. Out of the 27 characters examined 21 were found to be well correlated with geographical patterns. T. fuana was morphologically the most distant taxon, while T. sumatrana clustered among the T. wallichiana varieties. After correcting misidentifications of the specimens in T. wallichiana, its varieties occupied discrete geographical ranges, except for some limited sympatry of varieties mairei and chinensis east of the Tanaka,Kaiyong line and the Sichuan Basin, China. Our analysis demonstrates the importance of consistency in character selection and definition in the identification of morphologically difficult taxa and the power of combining morphometric and geographical data in clarifying their spatial distribution. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 307,335. [source] | |||||||||||||