Topologically Consistent Models for Efficient Big Geo-Spatio-Temporal Data Distribution

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

Wursthorn

2018

Self Cite

<p><strong>Abstract.</strong> The topological consistency of Boundary-Representation models, meaning here that the incidence graph is homeomorphic with the underlying topology of geographical data, is checked for several CityGML datasets, and a first classification of topological inconsistencies is performed. The analysis is carried out on a spatial database system into which the datasets have been imported. It is found that real-world datasets contain many topologically inconsistent pairs of intersecting polygons. Also data satisfying the ISO/OGC standards can still be topologically inconsistent. In the case when the intersection is a point, topological inconsistency occurs because a vertex lies on a line segment. However, the most frequent topological inconsistencies seem to arise when the intersection of two polygons is a line segment. Consequently, topological queries in present CityGML data cannot rely on the incidence graph only, but must always make costly geometric computations if correct results are to be expected.</p>

Section: Topological Consistencymentioning

confidence: 98%

Section: Related Workmentioning

confidence: 99%

Detection and Evaluation of Topological Consistency in Citygml Datasets

Giovanella

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

Wursthorn

2018

Self Cite

“…The definition of topological consistency here extends the definition of [9] and differs from that of [10] or [26]. Observe that our definition of topological consistency also includes the situation where the 'cells' of a complex are allowed to have polytope-shaped holes.…”

Section: Topological Consistencymentioning

confidence: 99%

“…Bradley [9] gives an overview of topological data models and introduces topological consistency in the context of smart cities. Jahn et al [10] give a first definition of topological consistency which relates geometry and the incidence graph in the context of distributed big geographical data, and define a measure for topological inconsistency based on Betti numbers of finite partially ordered sets. Alam et al [11] have a list of consistency rules for topology and semantics in which they do not allow more than two polygons to have a common edge.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Topological Consistency in CityGML

Giovanella

Wursthorn

2019

IJGI

Boundary representation models are data models that represent the topology of a building or city model. This leads to an issue in combination with geometry, as the geometric model necessarily has an underlying topology. In order to allow topological queries to rely on the incidence graph only, a new notion of topological consistency is introduced that captures possible topological differences between the incidence graph and the topology coming from geometry. Intersection matrices then describe possible types of topological consistency and inconsistency. As an application, it is examined which matrices can occur as intersection matrices, and how matrices from topologically consistent data look. The analysis of CityGML data sets stored in a spatial database system then shows that many real-world data sets contain many topologically inconsistent pairs of polygons. It was observed that even if data satisfy the val3dity test, they can still be topologically inconsistent. On the other hand, it is shown that the ISO 19107 standard is equivalent to our notion of topological consistency. In the case when the intersection is a point, topological inconsistency occurs because a vertex lies on a line segment. However, the most frequent topological inconsistencies seem to arise when the intersection of two polygons is a line segment. Consequently, topological queries in present CityGML data cannot rely on the incidence graph only, but must always make costly geometric computations if correct results are to be expected.

“…In the example, the input data is an LoD2 CityGML dataset of Erfurt, Thuringia. For the handling of topologically inconsistent data, we provide a conceptual model based on the Property Graph Model and OGC's General Feature Model ISO 19109 and Simple Feature Model ISO 19107 design patterns which have already been partly introduced in (Jahn et al, 2017) or (Breunig et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Computing Watertight Volumetric Models From Boundary Representations to Ensure Consistent Topological Operations

Jahn

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

2021

Self Cite

Abstract. To simulate environmental processes, noise, flooding in cities as well as the behaviour of buildings and infrastructure, ‘watertight’ volumetric models are a measuring prerequisite. They ensure topologically consistent 3D models and allow the definition of proper topological operations. However, in many existing city or other geo-information models, topologically unchecked boundary representations are used to store spatial entities. In order to obtain consistent topological models, including their ‘fillings’, in this paper, a triangulation combined with overlay and path-finding methods is presented by climbing up the dimension, beginning with the wireframe model. The algorithms developed for this task are presented, whereby using the philosophy of graph databases and the Property Graph Model. Examples to illustrate the algorithms are given, and experiments are performed on a data-set from Erfurt, Thuringia (Germany), providing complex geometries of buildings. The heavy influence of double precision arithmetic on the results, in particular the positional and angular precision, is discussed in the end.