scholarly journals A Modified Methodology for Generating Indoor Navigation Models

2019 ◽  
Vol 8 (2) ◽  
pp. 60 ◽  
Author(s):  
Elżbieta Lewandowicz ◽  
Przemysław Lisowski ◽  
Paweł Flisek
Keyword(s):  
Spatial Data ◽  
Medial Axis ◽  
Indoor Navigation ◽  
Medial Axis Transformation ◽  
Triangulated Irregular Networks ◽  
Modeled Structure ◽  
Irregular Networks ◽  
Thiessen Polygons ◽  
Automatic Methods ◽  
Traditional Approaches

Automatic methods for constructing navigation routes do not fully meet all requirements. The aim of this study was to modify the methodology for generating indoor navigation models based on the Medial Axis Transformation (MAT) algorithm. The simplified method for generating corridor axes relies on the Node-Relation Structure (NRS) methodology. The axis of the modeled structure (corridor) is then determined based on the points of the middle lines intersecting the structure (polygon). The proposed solution involves a modified approach to the segmentation of corridor space. Traditional approaches rely on algorithms for generating Triangulated Irregular Networks (TINs) by Delaunay triangulation or algorithms for generating Thiessen polygons known as Voronoi diagrams (VDs). In this study, both algorithms were used in the segmentation process. The edges of TINs intersected structures. Selected midpoints on TIN edges, which were located in the central part of the structure, were used to generate VDs. Corridor structures were segmented by polygon VDs. The identifiers or structure nodes were the midpoints on the TIN edges rather than the calculated centroids. The generated routes were not zigzag lines, and they approximated natural paths. The main advantage of the proposed solution is its simplicity, which can be attributed to the use of standard tools for processing spatial data in a geographic information system.

scholarly journals A Modified Methodology for Generating Indoor Navigation Models

2019 ◽  
Author(s):  
Elżbieta Lewandowicz ◽  
Przemysław Lisowski ◽  
Paweł Flisek
Keyword(s):  
Spatial Data ◽  
Medial Axis ◽  
Indoor Navigation ◽  
Medial Axis Transformation ◽  
Triangulated Irregular Networks ◽  
Modeled Structure ◽  
Irregular Networks ◽  
Thiessen Polygons ◽  
Automatic Methods ◽  
Traditional Approaches

Automatic methods for constructing navigation routes do not fully meet all requirements. The aim of this study was to modify the methodology for generating indoor navigation models based on the Medial Axis Transformation (MAT) algorithm. The simplified method for generating corridor axes relies on the Node-Relation Structure (NRS) methodology. The axis of the modeled structure (corridor) is determined based the points of the middle lines intersecting the structure (polygon). The proposed solution involves a modified approach to the segmentation of corridor space. Traditional approaches rely on algorithms to construct Triangulated Irregular Networks (TINs) by Delaunay triangulation or algorithms for generating Thiessen polygons known as Voronoi diagrams (VDs). In this study, both algorithms were used in the segmentation process. The edges of TINs intersect structures. Selected midpoints on TIN edges, which are located in the central part of the structure, are used to generate VDs. Polygon VDs segment corridor structures. The identifiers or structure nodes are the midpoints on TIN edges rather than the calculated centroids. The generated routes are not zigzag lines, and they approximate natural paths. The main advantage of the proposed solution is its simplicity which can be attributed to the use of standard tools for processing spatial data in a geographic information system.

scholarly journals A Method for Generating the Centerline of an Elongated Polygon on the Example of a Watercourse

2020 ◽  
Vol 9 (5) ◽  
pp. 304
Author(s):  
Elżbieta Lewandowicz ◽  
Paweł Flisek
Keyword(s):  
River Flow ◽  
Medial Axis ◽  
Hydraulic Structures ◽  
Vector Data ◽  
Triangulated Irregular Network ◽  
University Center ◽  
Medial Axis Transformation ◽  
Base Points ◽  
The City

The centerlines of polygons can be generated with the use of various methods. The aim of this study was to propose an algorithm for generating the centerline of an elongated polygon based on the transformation of vector data. The proposed method involves the determination of base points denoting the direction of river flow. These points were also used to map two polygon boundaries. A Triangulated Irregular Network (TIN) was created based on the polygon’s breakpoints. Edges that intersect the river channel in a direction perpendicular to river flow (across) were selected from a set of TIN edges. The polygon was partitioned into segments with the use of the selected TIN edges. The midpoints of selected TIN edges were used to generate the polygon’s centerline based on topological relations. The presented methodology was tested on a polygon representing a 15-km-long section of a river intersecting the city of Olsztyn (a university center). The analyzed river is a highly meandering watercourse, and its channel is narrowed down by hydraulic structures. The river features an island and distributary channels. The generated centerline effectively fits the polygon, and, unlike the solution modeled with the Medial Axis Transformation (MAT) algorithm, it does not feature branching streams.

Representation of 3-D elevation in terrain databases using hierarchical triangulated irregular networks: a comparative analysis

1998 ◽  
Vol 12 (8) ◽  
pp. 853-873 ◽  
Author(s):  
MAHDI ABDELGUERFI ◽  
CHRIS WYNNE ◽  
EDGAR COOPER ◽  
LADNER ROY
Keyword(s):  
Comparative Analysis ◽  
Triangulated Irregular Networks ◽  
Irregular Networks

Boundary Problem for Triangulated Irregular Networks

1993 ◽  
Vol 20 (4) ◽  
pp. 244-250 ◽  
Author(s):  
Steven T. Bower ◽  
Carlton M. Newton
Keyword(s):  
Boundary Problem ◽  
Triangulated Irregular Networks ◽  
Irregular Networks

The Radial Sweep Algorithm for Constructing Triangulated Irregular Networks

1982 ◽  
Vol 2 (3) ◽  
pp. 11-21 ◽  
Author(s):  
Mirante ◽  
Weingarten
Keyword(s):  
Triangulated Irregular Networks ◽  
Sweep Algorithm ◽  
Irregular Networks

scholarly journals INDOORGML – A STANDARD FOR INDOOR SPATIAL MODELING

2016 ◽  
Vol XLI-B4 ◽  
pp. 701-704
Author(s):  
Ki-Joune Li
Keyword(s):  
Spatial Data ◽  
Geometric Model ◽  
Spatial Models ◽  
Cell Number ◽  
Indoor Navigation ◽  
Location Based Services ◽  
Indoor Space ◽  
Outdoor Spaces ◽  
Core Module ◽  
Outdoor Space

With recent progress of mobile devices and indoor positioning technologies, it becomes possible to provide location-based services in indoor space as well as outdoor space. It is in a seamless way between indoor and outdoor spaces or in an independent way only for indoor space. However, we cannot simply apply spatial models developed for outdoor space to indoor space due to their differences. For example, coordinate reference systems are employed to indicate a specific position in outdoor space, while the location in indoor space is rather specified by cell number such as room number. Unlike outdoor space, the distance between two points in indoor space is not determined by the length of the straight line but the constraints given by indoor components such as walls, stairs, and doors. For this reason, we need to establish a new framework for indoor space from fundamental theoretical basis, indoor spatial data models, and information systems to store, manage, and analyse indoor spatial data. In order to provide this framework, an international standard, called IndoorGML has been developed and published by OGC (Open Geospatial Consortium). This standard is based on a cellular notion of space, which considers an indoor space as a set of non-overlapping cells. It consists of two types of modules; core module and extension module. While core module consists of four basic conceptual and implementation modeling components (geometric model for cell, topology between cells, semantic model of cell, and multi-layered space model), extension modules may be defined on the top of the core module to support an application area. As the first version of the standard, we provide an extension for indoor navigation.

scholarly journals Estimating the Precipitation Amount at Regional Scale Using a New Tool, Climate Analyzer

Hydrology ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 125
Author(s):  
Alina Bărbulescu ◽  
Florin Postolache ◽  
Cristian Ștefan Dumitriu
Keyword(s):  
Spatial Data ◽  
Regional Scale ◽  
Precipitation Amount ◽  
Precipitation Method ◽  
Time Interval ◽  
Precipitation Series ◽  
Distance Weighting ◽  
Thiessen Polygons ◽  
User Friendly

Different methods are known for interpolating spatial data. Introduced a few years ago, the initial version of the Most Probable Precipitation Method (MPPM) proved to be a valuable competitor against the Thiessen Polygons Method, Inverse Distance Weighting and kriging for estimating the regional trend of precipitation series. Climate Analyzer, introduced here, is a user-friendly toolkit written in Matlab, which implements the initial and modified version of MPPM and new selection criteria of the series that participate in estimating the regional precipitation series. The software provides the graphical output of the estimated regional series, the modeling errors and the comparisons of the results for different segmentations of the time interval used in modeling. This article contains the description of Climate Analyzer, accompanied by a case study to exemplify its capabilities.

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