191,314 research outputs found

    History of Soil Geography in the Context of Scale

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    We review historical soil maps from a geographical perspective, in contrast to the more traditional temporalā€“historical perspective. Our geographical approach examines and compares soil maps based on their scale and classification system. To analyze the connection between scale in historical soil maps and their associated classification systems, we place soil maps into three categories of cartographic scale. We then examine how categories of cartographic scale correspond to the selection of environmental soil predictors used to initially create the maps, as reflected by the maps\u27 legend. Previous analyses of soil mapping from the temporal perspective have concluded that soil classification systems have co-evolved with gains in soil knowledge. We conclude that paradigm shifts in soil mapping and classification can be better explained by not only their correlation to historical improvements in scientific understanding, but also by differences in purpose for mapping, and due to advancements in geographic technology. We observe that, throughout history, small cartographic scale maps have tended to emphasize climateā€“vegetation zonation. Medium cartographic scale maps have put more emphasis on parent material as a variable to explain soil distributions. And finally, soil maps at large cartographic scales have relied more on topography as a predictive factor. Importantly, a key characteristic of modern soil classification systems is their multi-scale approach, which incorporates these phenomena scales within their classification hierarchies. Although most modern soil classification systems are based on soil properties, the soil map remains a model, the purpose of which is to predict the spatial distributions of those properties. Hence, multi-scale classification systems still tend to be organized, at least in part, by this observed spatial hierarchy. Although the hierarchy observed in this study is generally known in pedology today, it also represents a new view on the evolution of soil science. Increased recognition of this hierarchy may also help to more holistically combine soil formation factors with soil geography and pattern, particularly in the context of digital soil mapping

    Seamless Online Distribution of Amundsen Multibeam Data

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    Since 2003, all underway multibeam and sub-bottom data from the Canadian Coast Guard Ship Amundsen has been posted online within approximately six months of the end of each cruise. A custom interface allowing the user to access 15\u27 latitude by 30\u27 longitude mapsheets was implemented in 2006, allowing the user to download the bathymetric and backscatter data at 10 metre resolution. While this interface matched the underlying data management scheme implemented at the University of New Brunswick, the zoom and pan capability was at a fixed scale with limited contextual data. In the past few years, with the introduction of web-based geographic information systems (GIS) (e.g. Google Maps, Yahoo Maps, Bing Maps), there have been thousands of maps published online. These online GIS programs are a suitable platform to display the seven years of Amundsen coverage within the context of the GIS-served satellite imagery and allow the user to freely browse all data in a familiar interface. The challenge, however, for serving up third party data through these map engines is to efficiently cope with the multiple zoom levels and changing resolutions. Custom tiling software was developed to take all the raw data from the seven years of Amundsen (and others\u27) multibeam coverage and convert it into multiple scale resolution images suitable for interpretation by Google Maps. The images were stored in a pyramid structure utilizing Google\u27s map projection and uniquely named to reflect their georeferencing and resolution. This image pyramid is then accessed by Google Maps according to the user\u27s current zoom level to optimize visualization. This multi-resolution data is served up on demand from the University of New Brunswick for dynamic overlay on Google\u27s satellite data. This web interface allows any interested parties to easily view multibeam and sub-bottom data from the Pacific Ocean through the Canadian Arctic Archipelago and into the Atlantic Ocean. The broad overview helps to understand regional trends and then focus on areas of interest at high resolutions to see particular features. The web interface also provides a link to the 15\u27 by 30\u27 mapsheet model with full source traceability

    Mojave Desert - Satellite Image Map

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    Produced for the Mojave Desert Ecosystem Program under the United States Department of Defense Legacy Program in cooperation with the Department of the Interior. Cartography and image processing by: Remote Sensing and Geographic Information Systems Laboratory Department of Geography and Earth Resources College of Natural Resources Utah State University Logan, Utah 84322ā€“5240 Cartographic preparation and printing by U.S. Geological Survey, 1998. Image map produced from 15 Landsat Thematic Mapper images recorded from 1991ā€“1993, provided by U.S. Geological Survey (USGS), as part of the Multiā€“Resolution Land Characteristics Consortium Activities. Bands 7, 4, 2. Simulated natural color composite. Land ownership compiled from 1:100,000-scale Bureau of Land Management Surface Management Status maps. Populated places produced from USGS Geographic Names Information System. Roads produced from USGS 1:100,000-scale Digital Line Graph data. Project boundary based on the Mojave Desert Section delineated by Robert G. Bailey, 1995, with a 50 kilometer buffer

    Expanding scales in GIS analysis

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    I propose to argue that the widely perceived opposition between a ā€œsite scaleā€ and ā€œregional scaleā€ in GIS analysis is not an optimal classification in archaeological practice. While stressing the importance of the conceptual separation of terms describing the dead and the living cultures I will suggest that projects should be approached in accordance to their theoretical background rather than their geographical extent. Since archaeological data is usually severely biased in diverse aspects, new analytical ā€œscalesā€ will be introduced into the debate, which allow to address questions previously inaccessible in GIS analysis. This approach is based on descriptive databases viewed as multi-dimensional spaces, regardless of the presence or absence of geographic coordinates. This paper concludes that useful GIS outputs need not look like decorative maps of the physical landscape, or distribution maps of finds, but that they can also present formalized abstract models built by the framework of a newly-coined term ā€œfact spaceā€

    The structure of borders in a small world

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    Geographic borders are not only essential for the effective functioning of government, the distribution of administrative responsibilities and the allocation of public resources, they also influence the interregional flow of information, cross-border trade operations, the diffusion of innovation and technology, and the spatial spread of infectious diseases. However, as growing interactions and mobility across long distances, cultural, and political borders continue to amplify the small world effect and effectively decrease the relative importance of local interactions, it is difficult to assess the location and structure of effective borders that may play the most significant role in mobility-driven processes. The paradigm of spatially coherent communities may no longer be a plausible one, and it is unclear what structures emerge from the interplay of interactions and activities across spatial scales. Here we analyse a multi-scale proxy network for human mobility that incorporates travel across a few to a few thousand kilometres. We determine an effective system of geographically continuous borders implicitly encoded in multi-scale mobility patterns. We find that effective large scale boundaries define spatially coherent subdivisions and only partially coincide with administrative borders. We find that spatial coherence is partially lost if only long range traffic is taken into account and show that prevalent models for multi-scale mobility networks cannot account for the observed patterns. These results will allow for new types of quantitative, comparative analyses of multi-scale interaction networks in general and may provide insight into a multitude of spatiotemporal phenomena generated by human activity.Comment: 9 page

    Constrained tGAP for generalisation between scales: the case of Dutch topographic data

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    This article presents the results of integrating large- and medium-scale data into a unified data structure. This structure can be used as a single non-redundant representation for the input data, which can be queried at any arbitrary scale between the source scales. The solution is based on the constrained topological Generalized Area Partition (tGAP), which stores the results of a generalization process applied to the large-scale dataset, and is controlled by the objects of the medium-scale dataset, which act as constraints on the large-scale objects. The result contains the accurate geometry of the large-scale objects enriched with the generalization knowledge of the medium-scale data, stored as references in the constraint tGAP structure. The advantage of this constrained approach over the original tGAP is the higher quality of the aggregated maps. The idea was implemented with real topographic datasets from The Netherlands for the large- (1:1000) and medium-scale (1:10,000) data. The approach is expected to be equally valid for any categorical map and for other scales as well
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