Análisis geoespacial para la caracterización funcional de las infraestructuras viarias en modelos de accesibilidad territorial utilizando sistemas de información geográfica

[Resumen] La aplicación de los Sistemas de Información Geográfica (SIG) sobre las infraestructuras viarias representa un importante reto en la ingeniería civil actual y del futuro. Bajo la teoría personal que defendemos en este proyecto, de que cualquier dato o saber manejado por el hombre es susceptible de representarse sobre la superficie terrestre, los SIG se convierten en un magnífico instrumento para aumentar el conocimiento humano sobre cualquier realidad. Las nuevas tecnologías ofrecen múltiples posibilidades para aportar datos a los SIG en cualquier campo, y por supuesto sobre las características y el funcionamiento de las carreteras. Pero se requieren nuevos enfoques, planteamientos y metodologías para tratar adecuadamente los datos viarios, y conseguir análisis más completos para una gestión más eficiente de estas infraestructuras. Esta tesis doctoral propone un método para realizar una parametrización mediante geometría de secuencia de puntos, que permite caracterizar todas las variables técnicas y funcionales que afectan o influyan sobre una infraestructura territorial de trazado lineal, en general, y particularmente sobre una red de carreteras. Gracias a la versatilidad que proporciona este método es posible asignar multitud de parámetros a cada sección del viario, provenientes de distintas fuentes de datos a través de diferentes tecnologías, y tratarlos convenientemente para generar nueva información a partir de ellos. También se permite realizar simplificaciones geométricas de la información mediante la tramificación temática según los aspectos que se necesite, para que pueda manejarse con mayor facilidad sobre los SIG, y ejecutar sobre esos datos diferentes métodos de análisis geoespacial. La funcionalidad de la red viaria puede analizarse desde múltiples perspectivas, pero sin duda una de las más eficientes y recomendables es mediante el cálculo de la accesibilidad que proporcionan las carreteras en un determinado territorio. Aunque existen gran variedad de modelos de cálculo de accesibilidad, el algoritmo de Coste Distancia basado en superficies de costes acumulados, se presenta como uno de los más interesantes sobre SIG, debido a la facilidad para incorporar datos al modelo ráster, y a que obtiene resultados de accesibilidad en cualquier lugar del ámbito geográfico analizado. Sin embargo su operativa de cálculo limita la aplicación de este algoritmo cuando se dispone de modos de desplazamiento especializados con limitación de accesos, como por ejemplo ocurre en vías de alta capacidad o prestaciones como autopistas, autovías, etc. En esta tesis doctoral se proponen dos métodos para superar esta limitación, mediante la Suma de Costes Parciales y con el algoritmo Coste Distancia Condicionado. Este último, además de conseguir modelar con gran fiabilidad cualquier modo transporte sobre la superficie terrestre, ofrece nuevas posibilidades de análisis sobre los modelos ráster gracias a la aplicación de restricciones condicionadas en los cálculos a ejecutar entre celdas vecinas. Las aplicaciones prácticas realizadas durante la investigación, de estos métodos, tanto la parametrización mediante geometrías de puntos, como los dos nuevos modelos de accesibilidad, muestran su grado de validez y eficacia para el análisis geoespacial de las infraestructuras viarias.[Resumo] A aplicación dos Sistemas de Información Xeográfica (SIX) sobre as infraestructuras viarias representa un importante reto na enxeñería civil actual e futura. Baixo a teoría persoal que defendemos neste proxecto, de que calquera dato ou saber manexado polo home é susceptible de representarse sobre a superficie terrestre, os SIX convértense nun magnífico instrumento para aumentar o coñecemento humano sobre calquera realidade. As novas tecnoloxías ofrecen múltiples posibilidades para aportar datos aos SIG en calquera campo, e por suposto sobre as características e o funcionamento das estradas. Pero requírense novos enfoques, formulacións e metodoloxías para tratar adecuadamente os datos viarios, e conseguir análises máis completas para unha xestión máis eficiente destas infraestructuras. Esta tese de doutorado propón un método para realizar unha parametrización mediante xeometría de secuencia de puntos, que permite caracterizar todas as variables técnicas e funcionales que afecten ou inflúan sobre unha infraestructura territorial de trazado lineal, en xeral, e particularmente sobre unha rede de estradas. Gracias á versatilidade que proporciona este método é posible asignar multitude de parámetros a cada sección do viario, provintes de distintas fontes de datos a través de diferentes tecnoloxías, e tratalos convenientemente para xerar nova información a partir deles. Tamén se permite realizar simplificacións xeométricas da información mediante a tramificación temática segundo os aspectos que se necesite, para que poida manexarse con maior facilidade sobre os SIX, e executar sobre eses datos diferentes métodos de análise xeoespacial. A funcionalidade da rede viaria pode analizarse desde múltiples perspectivas, pero sen dúbida una das máis eficientes e recomendables é mediante o cálculo da accesibilidade que proporcionan as estradas nun determinado territorio. Aínda que existen gran variedade de modelos de cálculo de accesibilidade, o algoritmo de Custo Distancia baseado en superficies de custos acumulados, preséntase como un dos máis interesantes sobre SIX, debido á facilidade para incorporar datos ao modelo ráster, e a que obtén resultados de accesibilidade en calquera lugar do ámbito xeográfico analizado. Con todo a súa operativa de cálculo limita a aplicación deste algoritmo cando se dispón de modos de desprazamento especializados con limitación de accesos, como por exemplo ocorre en vías de alta capacidade ou prestacións como autoestradas, autovías, etc. Nesta tese de doutoramento propóñense dous métodos para superar esta limitación, mediante a Suma de Custos Parciais e co algoritmo de Custo Distancia Condicionado. Este último, ademáis de conseguir modelar con gran fiabilidade calquera modo transporte sobre a superficie terrestre, ofrece novas posibilidades de análises sobre os modelos ráster gracias á aplicación de restriccións condicionadas nos cálculos a executar entre celas veciñas. As aplicacións prácticas realizadas durante a investigación, destes métodos, tanto a parametrización mediante xeometrías de secuencia de puntos, como os dous novos modelos de accesibilidade, mostran o seu grado de validez e eficacia para a análise xeoespacial das infraestructuras viarias.[Abstract] Application of Geographic Information Systems (GIS) on road infrastructure represents a major challenge in civil engineering of today and tomorrow. Under the personal theory that I defend in this project, namely that any data or knowledge handled by humans is likely to be represented over Earth’s surface, the GIS becomes a great tool for increasing human knowledge of any reality. New technologies offer many opportunities to provide GIS data in any field, and of course on the features and operation of the roads. But, new approaches, proposals and methodologies are needed to properly treat road data and get best analysis for a more efficient management of these infrastructures. This dissertation proposes a method to perform a parametrization using a sequence of points to characterize all technical and operating variables that affect or influence on a linear path infrastructure, in general, and particularly on a road network. Thanks to the versatility provided by this method it is possible to assign multiple parameters to each road section, from different data sources through different technologies, and treat them accordingly to generate new information from them. It also allows geometric simplifications of the information by connecting the dots on thematic stretchs, so it could be more easily handled on GIS, to run on these data different spatial analysis. Functionality of the road network can be analyzed from multiple perspectives, but certainly one of the most efficient and recommended is by calculating the accessibility provided by the roads in a given territory. Although there are a variety of methods for accessibility calculations, Cost Distance algorithm based on accumulated cost surfaces, is presented as one of the most interesting on GIS, because it is ease to incorporate raster data to the model, and because it gets results anywhere of the geographic region analyzed. However, its calculation method limits the application of this algorithm when there are specialized travel modes with limited access, such as occurs in high capacity roads. In this thesis, two methods are proposed to overcome this limitation by means of Partial Costs Sum algorithm and by means of Conditional Cost Distance algorithm. The latter, models with high reliability any transport mode on the surface, and offers new possibilities for analysis of raster models by applying conditional constraints to perform calculations between neighboring cells. Practical applications made during the investigation of these methods, parameterization by means sequence of points, and the two new models of accessibility, show their degree of validity and effectiveness for geospatial analysis of road infrastructure

Analysis of the Relationship between the Characteristics of the Areas of Influence of Bus Stops and the Decrease in Ridership during COVID-19 Lockdowns

[Abstract] This study aimed to investigate the relationship between the characteristics of the areas of influence of bus stops and the decrease in ridership during COVID-19 lockdowns and subsequent initial reopening processes. A novel GIS methodology was developed to determine these characteristics from a large amount of data with high spatial detail and accurately assign them to individual bus stops. After processing the data, several multiple linear regression models were developed to determine the variables related to different activities and changes in mobility during lockdown that may explain the variation in demand owing to the COVID-19 pandemic. The characteristics related to population and land use were also studied. The proposed methodology can be used to improve transit planning during exceptional situations, by strengthening public transport in areas with a predictably higher transit demand, instead of uniformly decreasing the availability of public transport services, promoting sustainable mobility. The efficiency of the proposed methodology was shown by performing a case study that analysed the variation in bus demand in A Coruña, Spain. The areas with the highest sustained demand were those with low inhabitant incomes, a high population density, and significant proportions of land use dedicated to hospitals, offices, or supermarkets.Grant RTI2018–097924–B–I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. Grant PRE2019-089651 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future

Residential Location Econometric Choice Modeling With Irregular Zoning: Common Border Spatial Correlation Metric

[Abstract] Residential location choice (RLC) predicts where and how people choose their residential location in the framework of land use–transport interaction models (LUTI). This paper seeks an efficient RLC model in the context of irregular zoning of location alternatives. The main current proposals in the field are discrete choice models. In RLC modeling, the alternatives are spatial units, and spatially correlated logit (SCL) is an efficient approach when the analyst cannot pre-define groups of alternatives that efficiently reflect the systematic substitution patterns among the alternatives. The SCL uses the spatial information on the contiguity of the zones to determine spatial correlation among the alternatives. Urban residential location choice usually uses administrative zoning, which is very irregular in many cities (mainly historic cities); however, SCL is not efficient in this context owing to the limitations of the binary contiguity spatial variable employed as a spatial correlation metric (SCM). This paper proposes an extension of the mixed SCL model, with an SCM based on the proportion of common border length in contiguous zones, which is more efficient in the irregular urban zoning context. The proposed model is applied to an urban case study of LUTI RLC modeling with irregular zoning, based on the administrative divisions of the city of Santander (Spain) and is shown to be empirically more efficient than the previous approaches.The authors acknowledge the financial support provided by the Government of Spain under the projects TRA2012-37659 and RTI2018-097924-B-I00 MCIU/AEI/FEDER, U

Automatic Generation of Urban Road 3D Models for Pedestrian Studies From LiDAR Data

[Abstract] The point clouds acquired with a mobile LiDAR scanner (MLS) have high density and accuracy, which allows one to identify different elements of the road in them, as can be found in many scientific references, especially in the last decade. This study presents a methodology to characterize the urban space available for walking, by segmenting point clouds from data acquired with MLS and automatically generating impedance surfaces to be used in pedestrian accessibility studies. Common problems in the automatic segmentation of the LiDAR point cloud were corrected, achieving a very accurate segmentation of the points belonging to the ground. In addition, problems caused by occlusions caused mainly by parked vehicles and that prevent the availability of LiDAR points in spaces normally intended for pedestrian circulation, such as sidewalks, were solved in the proposed methodology. The innovation of this method lies, therefore, in the high definition of the generated 3D model of the pedestrian space to model pedestrian mobility, which allowed us to apply it in the search for shorter and safer pedestrian paths between the homes and schools of students in urban areas within the Big-Geomove project. Both the developed algorithms and the LiDAR data used are freely licensed for their use in further research.This research study was funded by the Directorate-General for Traffic of Spain, grant number SPIP2017-0234

Direct Sensitivity Analysis of Multibody Systems With Holonomic and Nonholonomic Constraints via an Index-3 Augmented Lagrangian Formulation With Projections

This is a post-peer-review, pre-copyedit version of an article published in Nonlinear Dynamics. The final authenticated version is available online at: http://dx.doi.org/10.1007/s11071-018-4306-y[Abstract] Optimizing the dynamic response of mechanical systems is often a necessary step during the early stages of product development cycle. This is a complex problem that requires to carry out the sensitivity analysis of the system dynamics equations if gradient-based optimization tools are used. These dynamics equations are often expressed as a highly nonlinear system of Ordinary Differential Equations (ODEs) or Differential-Algebraic Equations (DAEs), if a dependent set of generalized coordinates with its corresponding kinematic constraints is used to describe the motion. Two main techniques are currently available to perform the sensitivity analysis of a multibody system, namely the direct differentiation and the adjoint variable methods. In this paper, we derive the equations that correspond to the direct sensitivity analysis of the index-3 augmented Lagrangian formulation with velocity and acceleration projections. Mechanical systems with both holonomic and nonholonomic constraints are considered. The evaluation of the system sensitivities requires the solution of a Tangent Linear Model (TLM) that corresponds to the Newton-Raphson iterative solution of the dynamics at configuration level, plus two additional nonlinear systems of equations for the velocity and acceleration projections. The method was validated in the sensitivity analysis of a set of examples, including a five-bar linkage with spring elements, which had been used in the literature as benchmark problem for similar multibody dynamics formulations, a point-mass system subjected to nonholonomic constraints, and a full-scale vehicle model.Ministerio de Economía y Competitividad (MINECO); DPI2016-81005-PXunta de Galicia; ED431B2016/03

La historia del río Monelos como servicio ecosistémico cultural y aproximación al estado de referencia para su restauración

[Resumen:] Desde la década de los años 60 del siglo XX hasta la actualidad, los cursos fluviales de la cuenca del río Monel os y sus afluentes, que comprende parte de los municipios de Arteixo y A Coruña, han sufrido las presiones urbanísticas de los nuevos crecimientos de áreas residenciales, industriales y comerciales, en un entorno urbano y periurbano. En este trabajo se analizan las transformaciones de la cuenca del río Monelos a lo largo de la historia, que ha supuesto la canalización de la mayor parte (aproximadamente el 60%) del recorrido superficial de sus cursos fluviales, mezclando sus aguas con el alcantarillado urbano de la ciudad de A Coruña. Se estudian las diferentes etapas de transformación del río, vinculadas al contexto histórico y al planeamiento urbano de la época. El objetivo final de este estudio es obtener una aproximación al estado de referencia original de la cuenca para a partir de él, reflexionar y diseñar una propuesta de restauración de los tramos más significativos, dentro del contexto de fomento de la infraestructura verde que se promueve desde las instituciones europeas, identificando y poniendo en valor los servicios ecosistémicos culturales que proporciona el río.[Abstract:] From the 1960s to the present day, the watercourses of the Monelos river basin and its tributaries, which includes part of the municipalities of Arteixo and A Coruña, have suffered the urban pressures of the new growth of residential, industrial and commercial areas, in an urban and peri -urban environment. This research analyses the transformations of the Monelos river basin throughout history, which has meant the channelling of most (approximately 90%) of their courses, mixing its waters with the urban sewer system of the city of A Coruña. The different stages of river transformation are studied, linked to the historical context and urban planning of the time. The final objective of this study is to obtain an approximation to the original reference state of the basin in order to reflect on it and design a proposal for the restoration of the most significant sections, within the context of the promotion of green infrastructure promoted by European institutions, identifying and valuing the cultural ecosystem services provided by the river

Characterizing zebra crossing zones using LiDAR data

Light detection and ranging (LiDAR) scanning in urban environments leads to accurate and dense three-dimensional point clouds where the different elements in the scene can be precisely characterized. In this paper, two LiDAR-based algorithms that complement each other are proposed. The first one is a novel profiling method robust to noise and obstacles. It accurately characterizes the curvature, the slope, the height of the sidewalks, obstacles, and defects such as potholes. It was effective for 48 of 49 detected zebra crossings, even in the presence of pedestrians or vehicles in the crossing zone. The second one is a detailed quantitative summary of the state of the zebra crossing. It contains information about the location, the geometry, and the road marking. Coarse grain statistics are more prone to obstacle-related errors and are only fully reliable for 18 zebra crossings free from significant obstacles. However, all the anomalous statistics can be analyzed by looking at the associated profiles. The results can help in the maintenance of urban roads. More specifically, they can be used to improve the quality and safety of pedestrian routesConsellería de Cultura, Educación e Ordenación Universitaria, Grant/Award Numbers: accreditation 2019-2022 ED431G-2019/04, 2022-2024, ED431C2022/16, ED481A-2020/231; European Regional Development Fund (ERDF); CiTIUS-Research Center in Intelligent Technologies of the University of Santiago de Compostela as a Research Center of the Galician University System; Ministry of Economy and Competitiveness, Government of Spain, Grant/Award Number: PID2019-104834GB-I00; National Department of Traffic (DGT) through the project Analysis of Indicators Big-Geodata on Urban Roads for the Dynamic Design of Safe School Roads, Grant/Award Number: SPIP2017-02340S

Biodiversidad y perspectivas para rehabilitar la cuenca del río Monelos (A Coruña, Galicia)

[Resumen:] Se detalla información acerca de la canalización del río de Monelos (A Coruña, Galicia) y sus afluentes, aportando datos sobre la diversidad y abundancia de especies de animales y plantas en la cuenca de este río antes, durante y después de estas obras. Se catalogan 620 especies hasta el año 2016, de las cuales 87 presentan un estado de conservación desfavorable a nivel gallego, español y/o mundial. Se proyectan varios escenarios de rehabilitación ambiental (parcial, total y total mejorada) de los cursos de agua de la cuenca del Monelos, y se valora su posible beneficio para la fauna y flora. Se concluye que sólo una rehabilitación total mejorada podría lograr recuperar valores de riqueza y abundancia de especies vinculadas al río semejantes a los previos a la canalización.[Abstract:] Details about the channeling of the Monelos river (A Coruña, Galicia) and its tributaries are provided, along with data on the diversity and abundance of animal and plant species in the basin of this river before, during and after these works. Up to 620 species were listed until 2016 in this basin; 87 of these had a unfavourable conservation status in Galicia, Spain and/or worldwide. Several environmental rehabilitation scenarios of the water courses of the Monelos river basin are projected and their possible benefit for fauna and flora is assessed. Only an improved rehabilitation would achieve values on species richness and abundance similar to those previous to the river channeling

Mapeando a eficiencia no consumo da auga

[Resumo] A enquisa sobre o consumo de auga desenvolta polo Emapic e a Oficina de Medio Ambiente da UDC é unha ferramenta en liña que ten por obxectivos crear o mapa da eficiencia no consumo de auga na Galiza e no mundo, aumentar a concienciación da poboación e reducir o gasto de auga mediante hábitos e equipamentos máis eficientes. Con metodoloxía sinxela no rexistro en vivendas e edificios públicos, fai uso das TIC para mellora da aprendizaxe de conceptos de sustentabilidade ambiental, fomentando hábitos de consumo responsábel. Unha vez feita a enquisa, a persoa participante recibe información e recomendacións para o aforro de auga, así como a comparación cos datos acumulados. Activa desde abril de 2018, conta actualmente con 150 rexistros, que poden referirse a un único baño, p.ex. vivenda, ou a todos os equipamentos dun edificio público, p.ex. facultade. Desta forma, xa inclúe 250 billas e 184 cisternas. Os resultados pódense consultar de forma libre e analizar segundo diferentes criterios: caudal medio das billas, tipo de cisternas, existencia de información para uso responsábel, presenza de sistemas aforradores de auga. A ferramenta é de especial utilidade para a educación ambiental e social, tanto non formal como en calquera dos niveis educativos, e para a xestión da auga nos ámbitos institucionais. Debería servir tamén para poñer en evidencia a entidades que seguen introducindo equipamentos ineficientes que derraman a auga que non temos.[Abstract] The water consumption survey developed by Emapic and the Office for the Environment UDC is an online tool that aims to create the map of water consumption efficiency in Galiza and the world, to increase public awareness and to reduce water spending through more efficient habits and equipment. Using a simple methodology in the registration of homes and public buildings, it makes use of ICTs to improve the learning of concepts for environmental sustainability, promoting responsible consumption habits. Upon completion of the survey, the participant receives information and recommendations for water saving as well as comparability with accumulated data. Active since April 2018, it currently has 150 records, which can refer to a single toilet, e.g. housing, or all the equipment of a public building, e.g. faculty. Thus, it already includes 250 taps and 184 tanks. The results are accessible for free and can be analyzed according to different criteria: average flow rate of taps, type of tanks, existence of information for responsible use, presence of water-saving systems. The tool is especially useful for environmental and social education, at any non-formal and formal educational levels, and for institutional water management. It should also serve to highlight entities that continue introducing inefficient equipment that spills the water that we don´t have.https://doi.org/10.17979/spudc.978849749775

An Augmented Reality Facility to Run Hybrid Physical-Numerical Flood Models

[Abstract] This article presents a novel installation for the development of hybrid physical-numerical flood models in an augmented reality environment. This installation extends the concept introduced by the well-known Augmented Reality-SandBox (AR-Sandbox) module, which presents a more educational, and less research-based and professional application. It consists of a physical scale topography built in a sandbox into which other elements (such as buildings, roads or dikes) can be incorporated. A scanner generates, in real time, a Digital Terrain Model (DTM) from the sandbox topography, which serves as a basis for the simulation of overland flow using professional hydraulic software (Iber+). The hydraulic and hydrological parameters (surface roughness, inlet discharges, boundary conditions) are entered with a simple Graphical User Interface (GUI) developed specifically for this project, as indeed was the entire system that allows the visualization of the simulation results. This allows us to obtain quantitative results of flood extension and magnitude, which are represented directly over the physical topography, yielding a realistic visual effect. This installation is conceived for both educational and professional uses. An example of its use is presented, through which its accuracy can be appreciated, and which also illustrates its potential.Xunta de Galicia; ED431E2018/1