Jose Martinez-Llario

Design and calibration of a 3D modeling system by videogrammetry

Nowadays, close-range photogrammetry and a laser scanner are the two most popular techniques in reconstruction of three-dimensional objects. This paper develops a methodology based on videogrammetry to reconstruct 3D objects more quickly than conventional photogrammetric techniques and more cheaply than a laser scanner. Videogrammetry allows the capture of thousands of points in a very short space of time (like a laser scanner) and the objects geometry and texture (frames are photographic images as stereo pairs). A system composed of a video camera and a turntable support with a double platform over it has been developed. This paper shows the design, construction and calibration of the system to model 3D objects contained on the support with pinpoint accuracy.

Design of a Java spatial extension for relational databases

Jaspa (Java Spatial) is a novel spatial extension for relational database management systems (RDBMSs). It is the result of a research project that aims to accomplish two goals: firstly, to fill the absence in the Free and Open Source Software (FOSS) world of a solid Java-based alternative to PostGIS, the leading spatial extension written in C. Secondly, to exploit the advantages of Java and the Java geospatial libraries over C in terms of portability and easiness to extend. Java programming for geospatial purposes is a flowering field and similar solutions to Jaspa have recently appeared, but none of them can equate with PostGIS due to lack of functionalities. Jaspa currently implements almost all PostGIS functionality. The next step will be the enrichment of the software with more sophisticated features: storage of spatial data in a topological structure within the RDBMS, cluster tolerance and geodetic functionalities. Jaspa is being developed at the Department of Cartographic Engineering, Geodesy and Photogrammetry of the Universidad Politecnica de Valencia and it has been published under an Open Source license on the OSOR.eu repository. This paper has been written by its creators with the aim of introducing users to its main capabilities.

Semi-automatic Process for Hybrid DTM Generalization based on Structural Elements Multi-analysis

Abstract The generalization of digital terrain models (DTMs) is a tool of great potential for simultaneous cartographic and photogrammetry generation processes at different scales, the main object of which is to feed different geographic information systems (GIS). These GIS enable multi-scale analysis and visualization through different data bases. This research proposes a semi-automatic DTM generalization process conditioned by a series of predefined parameters resulting in the generation of hybrid DTMs at different scales starting from a single cloud of points obtained through large-scale massive data acquisition processes. The generalization results obtained, applied on different areas of different relief, offer specific application ranks for each parameter with great precision, in contrast with DTMs obtained directly in each scale.

Three-diemensional scanner software using a video camera

This paper presents a software development for the obtaining in an automatic way of three-dimensional models of objects (e.g. sculptures, mechanical pieces). Nowadays, there is available software which is able to create three-dimensional models of objects using laser systems, but they are pretty expensive (up to 120,000 €) due to the high technology used for data capture (laser scanner). On the other hand, the software depicted in this paper develops a new process that captures the data with a simple digital video camera and a motorized pedestal (about 1200 €). This way, more than 1300 images of the object are obtained. The later analysis of the edges of all these images will completely define the geometry of the object. So, this software is able to create accurate digital models with a resolution that varies from hundreds to one million of points. In order to export these three-dimensional models the software generates VRML, or ASCII files. These models are very useful in sciences like computer graphics, architecture, mechanics, automated mapping/facilities management, etc.

Intersection and point-to-line solutions for geodesics on the ellipsoid

The paper presents two algorithms for the computation of intersection of geodesics and minimum distance from a point to a geodesic on the ellipsoid, respectively. They are based on the iterative use of direct and inverse problems of geodesy by means of their implementations with machine-precision accuracy in GeographicLib. The algorithms yield the same results as those obtained by Karney’s approach based on the use of auxiliary ellipsoidal gnomonic projections, with the advantage on our side that the algorithms are not limited to distances below 10000 km. This results in our algorithm being the only general solution for the problem of minimum distance from a point to a geodesic on the ellipsoid.

Mejora de la planificación temporal y adaptación de la metodología docente de la asignatura de IDEs del grado de Ingeniería Geomática mediante estadísticos de encuestas anónimas de horas dedicadas

En este articulo presentamos una metodologia docente adaptada para soportar tiempos de entrega de los contenidos practicas de una asignatura de forma muy flexible. Se busca dar la posibilidad al alumno de utilizar muchas mas horas que la media en un determinado modulo para asi evitar el envio de tareas incompletas o abandono de la asignatura. Para ello, se utilizan una serie de encuestas y con sus estadisticos se disena el cronograma de la asignatura para el curso siguiente. Ademas, se adapta la metodologia con docencia inversa y principalmente se adaptan todos los contenidos para dar la posibilidad al alumno de finalizar cualquier tarea fuera de horario docente. Palabras clave: gestion del tiempo, docencia inversa, encuesta, planificacion temporal, geomatica.

Analyzing and testing strategies to guarantee the topological relationships and quality requirements between networks inside BTA and BTU data models

Along this article we are going to explain some interesting strategies to reach the quality required for the phenomena considered inside the feature catalogue for the new BTA data model proposed by the Spanish Cartographic Norms Committee. We will focus on guaranteeing network connectivity, data accuracy and topological relationships between geometries of different phenomena. To reach our goal we will use ArcGIS software suite and its spatial analyst extension, building our own rules trying to automate the process and avoiding spending time to other interested users reusing our data model topology. The final goal of this work is to promote the migration to the new data model to earn interoperability between every cartographic producer by providing tools for potential users.