3D Topography. A Simplicial Complex-based Solution in a Spatial DBMS

Penninga, Friso

doi:10.54419/6fb987

Cited by 14 publications

(1 citation statement)

References 58 publications

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“…The solution proposed is valid not for 2.5D models but also for any boundary representations that can be triangulation (also for closed volumes), and the ideas are readily extensible to higher dimensions. As a consequence, the idea of storing stars of edges in 3D would permit us to efficiently store tetrahedra, and would offer an alternative to the structure of Penninga (2008).…”

Section: Discussionmentioning

confidence: 99%

Management of massive point cloud data: wet and dry

Oosterom¹,

Vosselman²,

Dijk³

et al. 2010

Publications on Geodesy - Green Series

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Management of massive point cloud data: wet and dry That the point cloud data model is a bit more complicated than just x, y, z values becomes clear when the LAS-format is presented, which allows in addition to store properties such as: intensity, return number, scan direction, classification, user data, r, g, b values, etc. For better dissemination of point cloud data this paper proposes a standardized Web Point Clouds Service (WPCS) in analogy with existing OGC web services. This service should support data streaming and the concept of Level of Details.The paper by Swart describes the properties of the Dutch digital terrain model AHN-2 and its potential use for water management purposes. With some 8 -10 points per square meter, the AHN-2 is likely to be the most detailed nationwide digital terrain model (DTM). Clearly, this also implies that the data amounts are enormous. The paper explains the need for such high point densities for various tasks of the water boards and the progress that has been made so far in the realisation of this DTM. Profiles drawn across dikes are used for stability analysis as well as for mapping toe lines. Several applications are reported to still work with height images instead of the original point clouds due to a lack of suitable software for handling the massive point clouds.Simons, Amiri-Simkooei, Siemes and Snellen (TU Delft) describe the recent developments in the processing of multi-beam echo sounder data by focussing on two applications, supported by case study results. Firstly, they emphasise the importance of correcting the MBES measurements for errors caused by the unknown sound speed in the water column (i.e. beam steering and conversions of beam angle and travel-time combinations), which may cause 'droopies' or 'smileys' in the across track direction. Their method exploits the redundancy of echo soundings in the overlap region between two adjacent swathes, so that no additional sound speed profile measurements are required. Simons et al. present a model that predicts the two-way travel times. By minimising the difference between the measurements and model predictions, optimised depths (or sounds speeds to recalculate the bathymetry) are obtained per ping. A case study of the Meuse near Rotterdam Harbour demonstrates that the artifacts due to unknown velocity profiles are successfully removed from the data (in real time) with an accuracy by which shallow beam-trawl tracks remain visible. Secondly, the variation in backscatter intensity, depending on incidence angle and thereby representing variations in seabed morphology and sediment characteristics, is used in the classification of sea bed sediments. Simons et al. present a new approach that uses backscatter measurements per angle and accounts for the ping-to-ping variability in backscatter intensity. Linear curve-fitting is used to obtain the best model to fit to the backscatter measurements of different sediment types and the difference between measurements and model results are minimised. Acoustic classes are identifi...

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Section: Discussionmentioning

confidence: 99%