5,825 research outputs found

    Cooperative Text and Line Art Extraction from a Topographic Map

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    The black layer is digitized from a USGS topographic map digitized at 1000 dpi. The connected components of this layer are analyzed and separated into line art, text, and icons in two passes. The paired street casings are converted to polylines by vectorization and associated with street labels from the character recognition phase. The accuracy of character recognition is shown to improve by taking account of the frequently occurring overlap of line art with street labels. The experiments show that complete vectorization of the black line-layer bitmap is the major remaining problem

    A combined measure for quantifying and qualifying the topology preservation of growing self-organizing maps

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    The Self-OrganizingMap (SOM) is a neural network model that performs an ordered projection of a high dimensional input space in a low-dimensional topological structure. The process in which such mapping is formed is defined by the SOM algorithm, which is a competitive, unsupervised and nonparametric method, since it does not make any assumption about the input data distribution. The feature maps provided by this algorithm have been successfully applied for vector quantization, clustering and high dimensional data visualization processes. However, the initialization of the network topology and the selection of the SOM training parameters are two difficult tasks caused by the unknown distribution of the input signals. A misconfiguration of these parameters can generate a feature map of low-quality, so it is necessary to have some measure of the degree of adaptation of the SOM network to the input data model. The topologypreservation is the most common concept used to implement this measure. Several qualitative and quantitative methods have been proposed for measuring the degree of SOM topologypreservation, particularly using Kohonen's model. In this work, two methods for measuring the topologypreservation of the Growing Cell Structures (GCSs) model are proposed: the topographic function and the topology preserving ma

    A Study of the Relationship Bettween Soil and Quantitative Terrain Factors

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    The objective of the study was to determine whether or not different soil areas in Hawaii could be separated by means of quantitative terrain factors. Eight great soil group areas on Oahu and six soil association areas on Kauai were selected. A sufficient number of 0.5-mile square test cells was established at random in each of the soil areas. Ten terrain factors were quantified in each of the test cells from data measured on either the topographic maps or the aerial photographs or both. The results showed that certain great soil groups on Oahu and certain soil associations on Kauai can be differentiated by their quantitative terrain factors. Average elevation, local relief, average slope, slope length, land texture ratio and drainage density were found effective in differentiating between these different groups and associations. Four terrain factors has been found effective in separating the Haplustox, Eutrorthox and Gibbsihumox areas on Oahu. These factors, in the order of decreasing effectiveness, were average slope, drainage density, slope length and local relief. The discriminant function equation developed for Tropohumult and Gibbsihumox areas, based on average elevation, average slope, slope length and drainage density, has satisfactorily segregated the two soil areas on Oahu. The results of the numerical grouping analysis of 108 test cells established in 0.5-mile grids in eastern Kauai indicated that numerical methods on the basis of several terrain factors has much to offer in reconnaissance soil surveys of large, relatively undeveloped regions where information about the soil is not available

    Application of remote sensing to state and regional problems

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    There are no author-identified significant results in this report

    Use of remote sensing techniques for geological hazard surveys in vegetated urban regions

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    The feasibility of using aerial photography for lithologic differentiation in a heavily vegetated region is investigated using multispectral imagery obtained from LANDSAT satellite and aircraft-borne photography. Delineating and mapping of localized vegetal zones can be accomplished by the use of remote sensing because a difference in morphology and physiology results in different natural reflectances or signatures. An investigation was made to show that these local plant zones are affected by altitude, topography, weathering, and gullying; but are controlled by lithology. Therefore, maps outlining local plant zones were used as a basis for lithologic map construction

    Inventory of available data elements for the San Bernardino, California region

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    Elements of data sets that are available to be integrated for the San Bernardino vertical data integration project are given. Each of the data sets has specified for it the ownership, validity, accuracy and technical requirements for integration

    The urban heritage characterization using 3D geographic information systems. The system of medium-sized cities in Andalusia

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    The primary objective of this paper is to approach the use of the 3D Geographic Information Systems (3D GIS), as an instrumental tool that allows us to deal efficiently with the extensive amount of information that characterises a large part of the research carried out in the field of Urbanism and Regional Planning. Specifically, the study focuses on medium-sized cities in Andalusia, the most populous and the second largest region in Spain. The Andalusian urban system is substantially characterised by the historical importance of this type of cities within its territorial organisation, which dates back to more than two thousand years, and whose potential as sustainable and balanced stands out. In particular, it is intended to address features related to urban characterisation as medium-sized cities that have been declared as heritage sites, as well as, the integration of the cultural heritage into urban development planning as an active strategy by the cultural administration of the regional and local governments. In detail, this paper will analyse data relating to the development experienced, their characterisation through urban indicators or the evolution and traceability of their protection. In this sense, the use of 3D GIS will not only allow the efficient recording and the graphical representation of a significant amount of data resulting from the quantitative and qualitative analysis carried out but also model them using the third dimension to facilitate a cross analysis among the cities under study. Definitely, the aim is to demonstrate the suitability use of this technology in this type of scientific research.Ministry of Economy and Competitiveness of the Government of Spain HAR2016-79788-

    Using airborne LiDAR Survey to explore historic-era archaeological landscapes of Montserrat in the eastern Caribbean

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    This article describes what appears to be the first archaeological application of airborne LiDAR survey to historic-era landscapes in the Caribbean archipelago, on the island of Montserrat. LiDAR is proving invaluable in extending the reach of traditional pedestrian survey into less favorable areas, such as those covered by dense neotropical forest and by ashfall from the past two decades of active eruptions by the Soufrière Hills volcano, and to sites in localities that are inaccessible on account of volcanic dangers. Emphasis is placed on two aspects of the research: first, the importance of ongoing, real-time interaction between the LiDAR analyst and the archaeological team in the field; and second, the advantages of exploiting the full potential of the three-dimensional LiDAR point cloud data for purposes of the visualization of archaeological sites and features
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