A Voronoi-Based Approach to Generating Depth-Contours for Hydrographic Charts

We introduce a new approach for the generation and the generalisation of visually smooth depth-contours for hydrographic charts. Unlike most current approaches, it strictly respects the safety constraint that dictates that the resulting chart may not indicate a depth shallower than originally measured. The main idea is to construct a smooth...

Sessie 5: Validation and Repair of 2D & 3D Data

Generation and generalization of safe depth-contours for hydrographc charts using a surface-based approach

Depth-contours are an essential part of any hydrographic chart|a map of a water-body intended for safe ship navigation. Traditionally these were manually drawn by skilled hydrographers from a limited set of surveyed depth measurements. Nowadays this process of map making is shifted towards the digital domain, not in the last place because of the...

Integrating Scale and Space in 3D City Models

This paper presents the problem of the current separate treatment of levels of detail in city models. We propose a solution, detail the main principles, and present our initial results on the approach. We conclude with work in progress and explain the benefits of our approach.

5D Modelling - applications and advantages

As explained in van Oosterom & Stoter (2012), the nD modeling approach allows us to include different aspects of geo-information in spatial modeling at a fundamental level, i.e. by treating these aspects as additional (geometric) dimensions. This paper explains how nD data models and data structures may solve the issues of redundancy and...

Automatically repairing invalid polygons with a constrained triangulation

Although the validation of single polygons has received considerable attention, the automatic repair of invalid polygons has not. Automated repair methods can be considered as interpreting ambiguous or ill-defined polygons and giving a coherent and clearly defined output. At this moment, automatic tools are not satisfactory and repairing is thus...

Een landsdekkende BGT, zonder gaten en overlap

Een van de uitdagingen van de Basisregistratie Grootschalige Topografie (BGT) is om de data afkomstig van de vele bronhouders samen te voegen tot één landsdekkende, topologisch correcte database. De regels in de BGT-catalogus zijn duidelijk en het combineren lijkt simpel. Maar de praktijk is weerbarstiger. In dit artikel leggen we uit waarom ...

Validation of planar partitions using constrained triangulations

Planar partitions—full tessellations of the plane into non-overlapping polygons—are frequently used in GIS to model concepts such as land cover, cadastral parcels or administrative boundaries. Since in practice planar partitions are often stored as a set of individual objects (polygons) to which attributes are attached (e.g. stored with a...

Topologically consistent 3D city models obtained by extrusion

One of the simplest methods to construct a 3D city model is to extrude building footprints to obtain \block-shaped" polyhedra representing buildings. While the method is well-known and easy to implement, if the 2D topological relationships between the footprints are not taken into account, the resulting 3D city models will not necessarily be...

Extruding building footprints to create topologically consistent 3D city models

One of the simplest methods to construct a 3D city model is to extrude building footprints, to obtain "block-shaped" buildings. While the method is well-known and easy to implement, if the topological relationships between the footprints are not taken into account, the resulting city models will not necessarily be topologically consistent. As a...