José P. Suárez

Mesh quality improvement and other properties in the four-triangles longest-edge partition

The four-triangles longest-edge (4T-LE) partition of a triangle t is obtained by joining the midpoint of the longest edge of t to the opposite vertex and to the midpoints of the two remaining edges. The so-called self-improvement property of the refinement algorithm based on the 4-triangles longest-edge partition is discussed and delimited by studying the number of dissimilar triangles arising from the 4T-LE partition of an initial triangle and its successors. In addition, some geometrical properties such as the number of triangles in each similarity class per mesh level and new bounds on the maximum of the smallest angles and on the second largest angles are deduced.

Forecasting and visualization of wildfires in a 3D geographical information system

This paper describes a wildfire forecasting application based on a 3D virtual environment and a fire simulation engine. A novel open-source framework is presented for the development of 3D graphics applications over large geographic areas, offering high performance 3D visualization and powerful interaction tools for the Geographic Information Systems (GIS) community. The application includes a remote module that allows simultaneous connections of several users for monitoring a real wildfire event. The system is able to make a realistic composition of what is really happening in the area of the wildfire with dynamic 3D objects and location of human and material resources in real time, providing a new perspective to analyze the wildfire information. The user is enabled to simulate and visualize the propagation of a fire on the terrain integrating at the same time spatial information on topography and vegetation types with weather and wind data. The application communicates with a remote web service that is in charge of the simulation task. The user may specify several parameters through a friendly interface before the application sends the information to the remote server responsible of carrying out the wildfire forecasting using the FARSITE simulation model. During the process, the server connects to different external resources to obtain up-to-date meteorological data. The client application implements a realistic 3D visualization of the fire evolution on the landscape. A Level Of Detail (LOD) strategy contributes to improve the performance of the visualization system.

A geometric diagram and hybrid scheme for triangle subdivision

We introduce a geometrical diagram to study the improvement in shape of triangles generated by iterative application of triangle subdivision. The four Triangles Longest Edge (4TLE) subdivision pattern and a new hybrid 4T Longest-Edge/Self-Similar (hybrid 4TLE-SS) scheme are investigated in this way. The map diagram provides a convenient way to visualize the evolution and migration of element shapes leading to a better understanding of the improvement process and the effect of recursive subdivision schemes. A complex variable mapping analysis supports the diagram and similarity class specifications. Numerical comparisons confirm the superiority of the new hybrid scheme.

An open source virtual globe framework for iOS, Android and WebGL compliant browser

The present article introduces the Glob3 Mobile, an efficient virtual globe framework, testable and freely accessible from the web and providing a real 3D navigation experience with smooth flying. We discuss the software design and the native code implementation for the family of iOS and Android mobile devices. In addition, a novel web experience is facilitated by supporting the globe through a WebGL compliant browser. Glob3 mobile enjoys a user friendly API that allows for testing and scripting new features on the globe. The paper discusses the software design, the technical rollout options and provides a comparison with other similar existing solutions.

An efficient terrain Level of Detail implementation for mobile devices and performance study

Abstract On the basis of traditional Terrain Quadtree algorithms this paper introduces a new Level Of Detail (LoD) criteria which allows the visualization of a virtual earth on many kinds of mobile devices with a suitable accuracy. The earth rendering system is intended to run beneath the threshold that resources of current devices impose, regarding especially the graphics hardware capabilities and the memory usage. At the same time, the system deals flawless with typical screen-based user interaction allowing smooth flying and rapid orientation changes of the camera. The present work analyses the memory and graphics requirements from a theoretical perspective. Finally, we give a useful performance study that compares the globe on some mobile and desktop devices, focusing on LoD techniques, visibility test, creation of texture tiles, uploading tiles to GPU, and rendering.

Refinement based on longest-edge and self-similar four-triangle partitions

The triangle longest-edge bisection constitutes an efficient scheme for refining a mesh by reducing the obtuse triangles, since the largest interior angles are subdivided. One of these schemes is the four-triangle longest-edge (4T-LE) partition. Moreover, the four triangle self-similar (4T-SS) partition of an acute triangle yields four sub-triangles similar to the original one. In this paper we present a hybrid scheme combining the 4T-LE and the 4T-SS partitions which use the longest-edge based refinement. Numerical experiments illustrate improvement in angles and quality. The benefits of the algorithm suggest its use as an efficient tool for mesh refinement in the context of Finite Element computations.

Four-triangles adaptive algorithms for RTIN terrain meshes

We present a refinement and coarsening algorithm for the adaptive representation of Right-Triangulated Irregular Network (RTIN) meshes. The refinement algorithm is very simple and proceeds uniformly or locally in triangle meshes. The coarsening algorithm decreases mesh complexity by reducing unnecessary data points in the mesh after a given error criterion is applied. We describe the most important features of the algorithms and give a brief numerical study on the propagation associated with the adaptive scheme used for the refinement algorithm. We also present a comparison with a commercial tool for mesh simplification, Rational Reducer, showing that our coarsening algorithm offers better results in terms of accuracy of the generated meshes.

SmartPort: A Platform for Sensor Data Monitoring in a Seaport Based on FIWARE

Seaport monitoring and management is a significant research area, in which infrastructure automatically collects big data sets that lead the organization in its multiple activities. Thus, this problem is heavily related to the fields of data acquisition, transfer, storage, big data analysis and information visualization. Las Palmas de Gran Canaria port is a good example of how a seaport generates big data volumes through a network of sensors. They are placed on meteorological stations and maritime buoys, registering environmental parameters. Likewise, the Automatic Identification System (AIS) registers several dynamic parameters about the tracked vessels. However, such an amount of data is useless without a system that enables a meaningful visualization and helps make decisions. In this work, we present SmartPort, a platform that offers a distributed architecture for the collection of the port sensors’ data and a rich Internet application that allows the user to explore the geolocated data. The presented SmartPort tool is a representative, promising and inspiring approach to manage and develop a smart system. It covers a demanding need for big data analysis and visualization utilities for managing complex infrastructures, such as a seaport.

Multimodal Location Based Services—Semantic 3D City Data as Virtual and Augmented Reality

The visualization of cross-domain spatial data sets has become an important task within the analysis of energy models. The representation of these models is especially important in urban areas, in which the under-standing of patterns of energy production and demand is key for an efficient city planning. Location Based Services (LBS) provide a valuable addition towards the analysis and visualization of those data sets as the user can explore the output of different models and simulations in the real environment at the location of interest. Towards this aim, the present research explores mobile alternatives to the visual analysis of temporal data series and 3D building models. Based on the fields of numerical simulation, GIS and computer graphics, this work presents a novel mobile service that allows exploring urban models at different Level of Details (LoDs) using well-known standards such as CityGML. Ultimately, the project enables researchers, city planners and technicians to explore urban energy datasets in an interactive and immersive manner as Virtual Globes, Virtual Reality and Augmented Reality. Using models of the city of Karlsruhe, the final service has been implemented and tested on the iOS platform providing an empirical insight on the performance of the system. In addition, this research provides a holistic approach by developing one application that is capable of seamlessly change the visualization mode.

Glob3 Mobile: An Open Source Framework for Designing Virtual Globes on iOS and Android Mobile Devices

The widely development of mobile devices is contributing to a high demand in 3D graphics, as they have also become a very important requirement of modern applications. Virtual Globes integrating environmental data at any time or place, remain a challenge within the technical constraints imposed by mobile devices. We present Glob3 Mobile, an open source framework for the development of virtual globes on familiar iOS and Android mobile devices. The paper discusses the design and development choices for each platform. The aim of this work is twofold. First, to provide an efficient Virtual Globe application, testable and freely accessible from the web and providing a truly 3D navigation experience with smooth flying. Second, to provide the main software components to easily design and implement 3D Virtual Globes based applications, on both iOS and Android platforms.