Mejora de la enseñanza de algoritmos SIG en la E.T.S.I. Geodésica, Cartográfíca y Topográfica de la Universidad Politécnica de Valencia

En el presente artículo se muestra una forma de trabajo que facilita la docencia de técnicas y algoritmos que se engloban dentro de la informática gráfica y en concreto dentro del área de los Sistemas de Información Geográfica (SIG). Al final del mismo, se analizan los resultados obtenidos sobre la metodología empleada teniendo en cuenta el contexto educativo en el que se desarrolla la experiencia

Torrents, barrancs i canalons, la xarxa de drenatge del Migjorn

Abstract not availabl

DISSEMINATION OF CULTURAL HERITAGE PROJECTS FOR WEB ENVIRONMENTS. FIRST EXPERIENCES USING THREE-JS LIBRARY

[EN] Dissemination of 3D information is a key process in cultural heritage projects. Most web-based platforms use WebGL technology for 3D data visualization. They normally provide generic wiewers with a low level of customization, however. By contrast, we usually find that Open Source based technologies allow for a complete adaptation to the specific project features by means of a large number of available dedicated javascript libraries. In the present paper we describe the minimum requirements any dissemination project should contain and the corresponding needs for implementation using Three-js, one of the most versatile Open Source 3D visualization libraries.[ES] Para cualquier proyecto relacionado con el estudio y conservación del patrimonio cultural, la fase de difusión de la información tridimensional debe ser una parte fundamental de todo el proceso. La mayoría de las plataformas existentes utilizan la tecnología WebGL para difundir contenido 3D a través de navegadores Web, aunque suelen ser de propósito genérico, con visores con bajo nivel de personalización. En el extremo opuesto están las tecnologías Open Source, representadas aquí por una serie de librerías programadas en lenguaje JavaScript que permiten un alto grado de adaptación a las necesidades de un proyecto específico. En el presente artículo se estudiarán las características mínimas que debería tener un proyecto de difusión en el campo del patrimonio cultural y su implementación en una de las librerías más utilizadas hoy día en los entornos de software libre, como es Three-js.Palomar Vázquez, JM.; Viñals Blasco, MJ. (2016). DIFUSIÓN DE PROYECTOS DE PATRIMONIO CULTURAL EN ENTORNOS WEB. PRIMERAS EXPERIENCIAS CON LA LIBRERÍA THREE-JS. En 8th International congress on archaeology, computer graphics, cultural heritage and innovation. Editorial Universitat Politècnica de València. 340-342. https://doi.org/10.4995/arqueologica8.2016.3579OCS34034

Characterizing beach changes using high-frequency Sentinel-2 derived shorelines on the Valencian coast (Spanish Mediterranean)

[EN] Shoreline position can be efficiently extracted with subpixel accuracy frommid-resolution satellite imagery using tools as SHOREX. However, it is necessary to develop procedures for deriving descriptors of the beach morphology and its changes in order to become truly useful data for characterizing the coastal dynamism. A new approach is proposed based on a spatiotemporal model of the beach widths. Divided into 80 m analysis segments, it offers a robust and detailed characterization of the beach state along large micro-tidal regions, with continuous information through time and space. Geographical and temporal differences can be recognized andmeasured, making it possible to study the beach response both to general factors (as wave conditions) and to punctual anthropic actions (as small sand nourishments). Widths were defined throughout two and a half years from 60 shorelines (3.04 m RMSE) covering 50 km of the Gulf of Valencia. Important width contrasts appeared along the study site associated with sediment imbalances motivated by sediment traps and other anthropic actions. Segments too narrow for maintaining the recreational function were located and mapped (16% narrower than 30 m). Short-term width changes appeared linked to storm events, with fast retreatments and slow recoveries. Punctually, even small-magnitude nourishments created perceptible changes in width (12,830 m(3) were associated with a 4 m increase). This novel description of the beach state and its changes from Satellite-Derived Shorelines is useful for coastal management, especially considering the global coverage of these free satellite images. It may improve the comprehension of coastal processes as well as monitor human interventions on the coast, helping in the decision making. (c) 2019 Elsevier B.V. All rights reserved.This study is supported by the contract of C. Cabezas-Rabadan (FPU15/04501) from the Spanish Ministry of Education, Culture and Sports, and by the project RESETOCOAST (CGL2015-69906-R) from the Spanish Ministry of Economy and Competitiveness.Cabezas-Rabadán, C.; Pardo Pascual, JE.; Palomar-Vázquez, J.; Fernández-Sarría, A. (2019). Characterizing beach changes using high-frequency Sentinel-2 derived shorelines on the Valencian coast (Spanish Mediterranean). The Science of The Total Environment. 691:216-231. https://doi.org/10.1016/j.scitotenv.2019.07.084S21623169

Shoreline Analysis and Extraction Tool (SAET): A New Tool for the Automatic Extraction of Satellite-Derived Shorelines with Subpixel Accuracy

[EN] SAET (Shoreline Analysis and Extraction Tool) is a novel open-source tool to enable the completely automatic detection of shoreline position changes using the optical imagery acquired by the Sentinel-2 and Landsat 8 and 9 satellites. SAET has been developed within the ECFAS (European Coastal Flood Awareness System) project, which is intended to be the first European service for coastal flood forecasting, management, and recovery analysis. The tool is developed to characterise the shoreline response associated with punctual events such as coastal storms as well as any other phenomenon. For a given beach segment, SAET facilitates the selection of the satellite images closest in time to the analysed events that offer an adequate cloud coverage level for analysing the shoreline change. Subsequently, the tool automatically downloads the images from their official repositories, pre-processes them and extracts the shoreline position with sub-pixel accuracy. In order to do so, an initial approximate definition of the shoreline is carried out at the pixel level using a water index thresholding, followed by an accurate extraction operating on the shortwave infrared bands to produce a sub-pixel line in vector formats (points and lines). The tool offers different settings to be adapted to the different coastal environments and beach typologies. Its main advantages refer to its autonomy, its efficiency in extracting complete satellite scenes, its flexibility in adapting to different environments and conditions, and its high subpixel accuracy. This work presents an accuracy assessment on a long Mediterranean sandy beach of SDSs extracted from L8 and S2 imagery against coincident alongshore reference lines, showing an accuracy of about 3 m RMSE. At the same time, the work shows an example of the usage of SAET for characterising the response to Storm Gloria (January 2020) on the beaches of Valencia (E Spain). SAET provides an efficient and completely automatic workflow that leads to accurate SDSs while only relying on publicly available information. The tool appears to be a useful extraction tool for beach monitoring, both for public administrations and individual users.The ECFAS (European Coastal Flood Awareness System) project (https://www.ecfas.eu/) has received funding from the EU H2020 research and innovation programme under Grant Agreement No. 101004211. This research is also supported by the projects MONOBESAT (PID2019-111435RB-I00) funded by the Spanish Ministry of Science, Innovation and Universities, and the Margarita Salas contract within the Re-qualification programme by the Ministry of Universities financed by the European Union¿NextGenerationEU and the grant Primeros Proyectos de Investigación (PAID-06-22), Vicerrectorado de Investigación de la Universitat Politècnica de València (UPV) associated with the corresponding author.Palomar-Vázquez, J.; Pardo Pascual, JE.; Almonacid-Caballer, J.; Cabezas-Rabadán, C. (2023). Shoreline Analysis and Extraction Tool (SAET): A New Tool for the Automatic Extraction of Satellite-Derived Shorelines with Subpixel Accuracy. Remote Sensing. 15(12). https://doi.org/10.3390/rs15123198151

Application of a combination of digital image processing and 3D visualization of graffiti in heritage conservation

[EN] In recent years, heritage documentation processes have largely benefited from the application of both 2D imagery analysis and 3D techniques for recording and visualization of assets. In this paper, a combined 2D-3D methodological workflow, especially helpful for the documentation of graffiti on closed and narrow spaces, is presented. It is proposed, firstly, the use of structure from motion software to obtain the 3D model and texture information. Then, the use of decorrelation stretching algorithms is used to obtain enhanced textures. This study found that the performance of the algorithms usually recommended for enhancement of the different colours is sometimes suboptimal. Finally, the integration of 2D and 3D information into Blender, a powerful 3D open-source tool, allows for a detailed exploration of the areas containing graffiti. Additionally, it allows high quality rendition of the resulting model that helps to better understand and record heritage resources. This methodological approach has been applied to the military defense heritage site of Puig-Carassols trench line in Spain.Palomar-Vázquez, J.; Baselga Moreno, S.; Viñals Blasco, MJ.; García-Sales, C.; Sancho-Espinós, I. (2017). Application of a combination of digital image processing and 3D visualization of graffiti in heritage conservation. Journal of Archaeological Science Reports. 12:32-42. doi:10.1016/j.jasrep.2017.01.021S32421

Using street based metrics to characterize urban typologies

[EN] Urban spatial structures reflect local particularities produced during the development of a city. High spatial resolution imagery and LiDAR data are currently used to derive numerical attributes to describe in detail intra-urban structures and morphologies. Urban block boundaries have been frequently used to define the units for extracting metrics from remotely sensed data. In this paper, we propose to complement these metrics with a set of novel descriptors of the streets surrounding the urban blocks under consideration. These metrics numerically describe geometrical properties in addition to other distinctive aspects, such as presence and properties of vegetation and the relationship between the streets and buildings. For this purpose, we also introduce a methodology for partitioning the street area related to an urban block into polygons from which the street urban metrics are derived. We achieve the assessment of these metrics through application of a one-way ANOVA procedure, the winnowing technique, and a decision tree classifier. Our results suggest that street metrics, and particularly those describing the street geometry, are suitable for enhancing the discrimination of complex urban typologies and help to reduce the confusion between certain typologies. The overall classification accuracy increased from 72.7% to 81.1% after the addition street of descriptors. The results of this study demonstrate the usefulness of these metrics for describing street properties and complementing information derived from urban blocks to improve the description of urban areas. Street metrics are of particular use for the characterization of urban typologies and to study the dynamics of cities.The authors appreciate the financial support provided by the Spanish Ministry of Science and Innovation in the framework of the project CGL2010-19591/BTE, and the data made available by the Spanish Instituto Geográfico Nacional (IGN)Hermosilla, T.; Palomar-Vázquez, J.; Balaguer Beser, ÁA.; Balsa Barreiro, J.; Ruiz Fernández, LÁ. (2014). Using street based metrics to characterize urban typologies. Computers, Environment and Urban Systems. 44:68-79. https://doi.org/10.1016/j.compenvurbsys.2013.12.002S68794

Analysis of the morphological changes of the beaches along the segment València - Cullera (E Spain) from satellite-derived shorelines

Beaches are spaces of paramount importance for coastal societies currently threatened by coastal erosion. Their preservation requires accurate quantification of their changes in order to understand their behavior and to propose efficient solutions. Landsat 8 and Sentinel 2 mid-resolution satellites offer free-of-charge images with great potential for coastal monitoring. From them, it is possible to automatically extract the shoreline position as a quantitative indicator of the beach morphology over large territories and with high temporal frequency. Beach changes take place at different spatial and temporal scales, typically responding to coastal storms and human interventions on the coast. The collection of large packages of satellite-derived shorelines (SDS) at the coastal sector València-Cullera (W Mediterranean) covering the period 2013-2020 makes it possible to characterize the state of its beaches and their width changes over space and time. Results reveal a widespread erosional trend, most likely caused by a shortage of sediment in the coastal system. Thus, the majority of the beaches are not capable of restoring their previous conditions after storm-driven retreats. The information provided by the SDS also shows the ineffectiveness of the nourishment actions, at least in the way they have been carried out, and the urgent need for a strategy to address the erosion problem

Diseño de una solución cartográfica para móviles en zonas de montaña. Aplicación para el Parque Natural del Montseny

En este artículo se describe el diseño y la implementación de una aplicación de visualización y consulta de la cartografía del Parc Natural del Montseny (Girona) optimizada para dispositivos móviles, para ser utilizada tanto en modo on-line como en modo off-line. El sistema permite la visualización de varios niveles de detalle, así como la consulta de la información cartográfica. Para el diseño de la aplicación se han tenido en cuenta diferentes aspectos y requerimientos: permite la conexión on-line a la cartografía o la descarga directa para un funcionamiento autónomo; permite la utilización de geolocalización vía GPS o también QR-Code (para zonas sin cobertura); y finalmente incorpora un sistema de almacenamiento de los atributos basado en la codificación de los mismos en la propia imagen. La aplicación ha sido implementada en J2ME y tiene en cuenta la resolución y el tamaño de pantalla del dispositivo móvil.Palomar-Vázquez, J.; Pardo Pascual, JE.; Peiró Simó, MJ. (2012). Diseño de una solución cartográfica para móviles en zonas de montaña. Aplicación para el Parque Natural del Montseny. Mapping. (154):16-24. http://hdl.handle.net/10251/35331S162415

Data Mining Paradigm in the Study of Air Quality

Air pollution is a serious global problem that threatens human life and health, as well as the environment. The most important aspect of a successful air quality management strategy is the measurement analysis, air quality forecasting, and reporting system. A complete insight, an accurate prediction, and a rapid response may provide valuable information for society’s decision-making. The data mining paradigm can assist in the study of air quality by providing a structured work methodology that simplifies data analysis. This study presents a systematic review of the literature from 2014 to 2018 on the use of data mining in the analysis of air pollutant measurements. For this review, a data mining approach to air quality analysis was proposed that was consistent with the 748 articles consulted. The most frequent sources of data have been the measurements of monitoring networks, and other technologies such as remote sensing, low-cost sensors, and social networks which are gaining importance in recent years. Among the topics studied in the literature were the redundancy of the information collected in the monitoring networks, the forecasting of pollutant levels or days of excessive regulation, and the identification of meteorological or land use parameters that have the most substantial impact on air quality. As methods to visualise and present the results, we recovered graphic design, air quality index development, heat mapping, and geographic information systems. We hope that this study will provide anchoring of theoretical-practical development in the field and that it will provide inputs for air quality planning and management.Facultad de Ciencias Exacta