6 research outputs found
Generation of High Spatial Resolution Terrestrial Surface from Low Spatial Resolution Elevation Contour Maps via Hierarchical Computation of Median Elevation Regions
We proposed a simple yet effective morphological approach to convert a sparse
Digital Elevation Model (DEM) to a dense Digital Elevation Model. The
conversion is similar to that of the generation of high-resolution DEM from its
low-resolution DEM. The approach involves the generation of median contours to
achieve the purpose. It is a sequential step of the I) decomposition of the
existing sparse Contour map into the maximum possible Threshold Elevation
Region (TERs). II) Computing all possible non-negative and non-weighted Median
Elevation Region (MER) hierarchically between the successive TER decomposed
from a sparse contour map. III) Computing the gradient of all TER, and MER
computed from previous steps would yield the predicted intermediate elevation
contour at a higher spatial resolution. We presented this approach initially
with some self-made synthetic data to show how the contour prediction works and
then experimented with the available contour map of Washington, NH to justify
its usefulness. This approach considers the geometric information of existing
contours and interpolates the elevation contour at a new spatial region of a
topographic surface until no elevation contours are necessary to generate. This
novel approach is also very low-cost and robust as it uses elevation contours.Comment: 11 pages, 6 figures,1 table, 1 algorith
Improved Morphological Interpolation of Elevation Contour Data with Generalised Geodesic Propagations
The objective of this work is to show how geodesic propagation techniques known in mathematical morphology can be employed to reconstruct terrain surfaces, and more generally grid data, from contour maps. We present the so-called generalised geodesic distance that was briefly introduced in a previous article. The shortest paths defined by the generalised geodesic distance can be used to linearly interpolate a given set of contour lines. We extend this concept by incorporating the knowledge of slope values over the contours and perform either Hermite interpolation with this distance or linear interpolation, but with a new weighted geodesic propagation function. Experiments are carried out over synthetic elevation data for which they result in nicely interpolated surfaces. The methodology is generic in the sense that it could be used to reconstruct any 2D or 3D digitised shape from its boundaries.JRC.H.6-Spatial data infrastructure
Abstracts on Radio Direction Finding (1899 - 1995)
The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography).
Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM.
The contents of these files are:
1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format];
2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format];
3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion