José I. Rodrigues

Cave Chamber Data Modeling and 3D Web Visualization

Underground caves and its specific structures are important for geomorphological studies. In this paper we present tools to identify and map speleothems by surveying cave chambers interiors. The cave chamber was surveyed using Terrestrial Laser Scanning to acquire point clouds with high level of detail for 3D model generation. This data with 45 million points is useful for either reconstruction, geomorphological studies or virtual visits of caves. With this point cloud we generated a 3D-mesh to represent the surface model of the cave chamber, which is important to study its geomorphological features. A topological structure of the 3D-mesh was also implemented to get an efficient algorithm to help identifying stalactites. The possibility to publish 3D data on the Web is of particular interest for the geospatial field. For this reason, it was decided to make the cave model available in the Web by developing a 3D graphical interface where users can navigate and interact with the three-dimensional models of the cave. For this Web3D framework it was used X3D, WebGL and X3DOM. Such solution does not require any additional plug-ins or components.

Locating a low-level waste disposal site

A model is developed to locate a waste disposal site for low-level (domestic and nontoxic industrial) waste. Account is taken of nuisance caused to population along routes and of equity considerations. Not only is equity as regards effects on different population centres considered, but also between carriers of waste from different towns giving rise to the concept of routing fairness. The resulting model problem is computationally complex and heuristic solution procedures are developed. These are applied to real data relating to the district of Algarve, Portugal, and results of numerical experiments are reported.

High-resolution digital 3D models of Algar do Penico Chamber: limitations, challenges, and potential

and/or complex terrains (Pucci & Marambio, 2009; Roncat et al., 2011). Accordingly, with the objective of producing a cave map that identifies the main interior speleothem structures for the purposes of palaeoenvironmental reconstruction, we conducted a terrestrial laser-based survey in a limestone cave. However, rather than just obtaining a map, the present study also aimed to expand 3D-mesh analysis, including the development of two algorithms for determination of stalactite extremities and contour lines, and the interactive visualization of 3D meshes on the Web. The chosen cave is known by local speleologists as Algar do Penico or Algar Guedes (Cavaco, pers. comm.), and is located in the Algarve region in southern Portugal. In this paper, we generate 3D-mesh models of the cave by using surface-reconstruction algorithms. These models can be used to study geomorphological structures and are able to be visualized on graphical interfaces. Several different options are presented for rendering models with high levels of detail from the same point cloud data set. For Web visualization, the selected model is simplified using a decimation method that reduces the download time. We adopt a framework

Web3DGIS for City Models with CityGML and X3D

There is an increasing interest in 3D Geographical Information Systems which leads to the development of web based technologies for visualization, interaction and query of 3D city models. The Open Geographic Consortium developed the City Geography Markup Language as an industry standard for the modeling of city objects. The web 3D Consortium established the eXtendable 3D standard for display of 3D scenes over the internet. This paper presents a Web3DGIS system that loads a cityGML model and convert it to a X3D model. This model can be viewed in the web. Moreover, it also allows the query about attributes and adjacency relationships of features in GIS data sets. For this Web3DGIS it was used X3D, WebGL and X3DOM. Such solution does not require any additional plug-ins or components.

A topological framework for interactive queries on 3D models in the Web.

Several technologies exist to create 3D content for the web. With X3D, WebGL, and X3DOM, it is possible to visualize and interact with 3D models in a web browser. Frequently, three-dimensional objects are stored using the X3D file format for the web. However, there is no explicit topological information, which makes it difficult to design fast algorithms for applications that require adjacency and incidence data. This paper presents a new open source toolkit TopTri (Topological model for Triangle meshes) for Web3D servers that builds the topological model for triangular meshes of manifold or nonmanifold models. Web3D client applications using this toolkit make queries to the web server to get adjacent and incidence information of vertices, edges, and faces. This paper shows the application of the topological information to get minimal local points and iso-lines in a 3D mesh in a web browser. As an application, we present also the interactive identification of stalactites in a cave chamber in a 3D web browser. Several tests show that even for large triangular meshes with millions of triangles, the adjacency and incidence information is returned in real time making the presented toolkit appropriate for interactive Web3D applications.

Framework for 3D data modeling and web visualization of underground caves using open source tools

Terrestrial Laser Scanning is a very useful technique for cave studies. This surveying method creates point clouds with high detail levels for 3D model generation, which is indeed useful for either reconstruction, geomorphological studies or virtual visits of caves. The present work generated a 3D model of a cave chamber and developed a framework for 3D data visualization on the Web. Identifying geomorphological structures is one of the goals of this project. The generated 3D-mesh represents the surface model of the cave chamber, which is important to study its geomorphological features. A topological structure of the 3D-mesh was implemented to get an efficient algorithm to help determining stalactites. The recognition and positioning of cave stalactites can provide information on hidden cave features responsible for cave geomorphology. The possibility to publish 3D data on the Web is of particular interest for the geospatial field. For this reason, it was decided to make the cave model available in the Web by developing a 3D graphical interface where users can navigate and interact with the three-dimensional models of the cave. For this Web framework, X3D, WebGL and X3DOM were used. Such solution does not require any additional plug-ins or components.

Web3D Visualization of High Detail and Complex 3D-mesh Caves Models

This paper presents the novel architecture of a web3D server that stores 3D models with different levels of detail and complexity that enables the interactive visualization and navigation in a web browser and the determination of detailed geomorphological structures of an underground cave. We surveyed an underground cave using a Terrestrial Laser Scanning to acquire a high-level detail point cloud with millions of points. This data allowed generating a high detail 3D-mesh to represent the surface model of the cave chamber, which can be important in studying geomorphological features. The web3D server uses a simplified version of the cave with about 250 thousand triangles that enables client applications to navigate and interact with this simplified model in a Web browser. The more detailed and complex model of the cave with millions of triangles is also stored in the web3D server. This model is used for the identification of geomorphological structures. It provides topological and geometrical information that is implemented in an octree data structure for the design of efficient algorithms to determine important speleothems and stored in a database to make it possible to work with big data models that can exceed the computers memory.

The Development of Indicators of Sustainable Mobility Associated with an Urbanism of Proximity. The Case of the City of Faro

Sustainable urban mobility contributes to a healthier life for the citizen, to the environmental quality of the urban environment and to social inclusion.

3D Modeling of the Milreu Roman Heritage with UAVs

In this paper we present a methodology to build a 3D model of a roman heritage site in the South of Portugal, known as Milreu, covering a region of about one hectare. Today’s Milreu ruins, a national heritage site, were once part of a 4rd century, luxurious villa-style manor house, which was subsequently converted into a thriving farm. Due to its relevance, it is important to make the 3D model of the Milreu ruins, to be available for the exploration in the Web and for virtual and augmented reality applications for mobile devices. This paper demonstrates the use of UAVs for the reconstruction of the 3D models of the ruins from vertical and oblique aerial photographs. To enhance the model quality and precision, terrestrial photographs were also incorporated in the workflow. This model is georeferenced, which give us the possibility to automatically determine accurate measurements of the Roman structures.

Geometrical and Topological Modelling: A Fast Computation of Spatial 3D TLS Data Selections

Underground caves and their specific structures are important for geomorphological studies. In this paper we present a new tool to identify and map speleothems by surveying cave chambers interiors. One of the research problems that we had to solve was that we were dealing with a great number of points that resulted from the Laser scan. The cave chamber was surveyed using Terrestrial Laser Scanning to acquire point clouds with high level of detail for 3D model generation. A point cloud of 45 million points was generated. This data set is important for either reconstruction of the 3D model, geomorphological studies or virtual visits to the cave. With this point cloud we generated a 3D-mesh to represent the surface model of the cave chamber. In this paper we present an octree data structure implemented using SQLite relational database management. Furthermore, it is also possible to work with several data models simultaneously, in such a way that it is not limited by computer memory resources. A topological structure of the 3D-mesh was also implemented to get an efficient algorithm to help identifying stalactites and stalagmites from big data 3D models of high detail.