How to build a city in three dimensions?

• The University of Salamanca and the University of Vigo developed a laser able to scan and virtually reproduce a city.
• The device will be very useful in the architectural, geographic and infrastructural fields.

How to build a city in three dimensions?The University of Salamanca, in conjunction with the University of Vigo, has developed the most innovative tool in the field of architectural practice: a laser photographing buildings, get of them all the information possible and provides accurate 3D views.
The device, which has several cameras and laser sensors, has been installed in a van to go through the cities. This tool transforms reality first to point clouds and, later, in three-dimensional images.
“They have a laser system that gives three-dimensionality, a photographic system that gives skin to the three-dimensional geometry, GPS and a very powerful inertial system that defines the path we follow in motion,” explains Diego González Aguilera, professor at the University of Salamanca Avila.
This system allows you to scan a city like Ávila in just two days with an accurate diagnosis. Classic tools require nearly two months and much higher costs.
The practical utility of this technique is to facilitate the restoration and reconstruction of dilapidated buildings, and allow to virtually visit cities. Furthermore the tool can apply to ports or railways.
Pablo Arias, a professor at the University of Vigo, widens the scope of the device: “It will allow us to do studies from energy efficiency in buildings to plan maintenance activities in all that is infrastructure”.

The practical utility of this technique is to facilitate the restoration and reconstruction of dilapidated buildings, and allow to virtually visit cities. Furthermore the tool can apply to ports or railways.The practical utility of this technique is to facilitate the restoration and reconstruction of dilapidated buildings, and allow to virtually visit cities. Furthermore the tool can apply to ports or railways.

How to build a city in three dimensions?

A final year project in Topography, led by Diego González Aguilera, get the Third Prize “San Isidoro 2010”.

The project applies laser and photogrammetric geotechnologies to digitalize the Castle of Turégano (Segovia) and has been awarded by one of the most important national awards in surveying.

A final year project in Topography“Application of laser and photogrammetric geotechnologies in the digitization of complex scenarios: Castle of Turégano (Segovia)” is the title of a project of Ana Martín de Frutos and Saúl Javier Yáñez Díaz and directed by Professor of the University of Salamanca Diego González Aguilera. It is a final year project to undertake documentation and dimensional modeling through nondestructive geotechnologies applied to the Castle of Turégano (Segovia) and for which the authors have obtained the third prize San Isidoro 2010, awarded by the College of Engineers Surveying.
As González Aguilera explained “San Isidoro awards are the most important awards at the national level for final projects in Surveying Engineering degree.” He also stressed that in the Polytechnic School of Ávila is not the first time they get one of these prestigious awards, as “in addition to this third prize, in the last five years we have achieved three first prizes.”
The ultimate goal of this geotechologies such as laser and photogrammetric application project to the complex stage of the Castle of Turégano, “is to have a rigorous mapping document that can be exploited by the different agents involved in the work of restoration and conservation of architectural heritage,” the authors explain in the summary of their work.
To do this they processed the point clouds collected by different field stations in order to optimize the time of capture. This work is streamlined reducing the scanning resolution to 100 dots per square meter, resolution enough for its objective since its aim was to transfer the tedious task involved in the model vectorization.
Thus, the work of Martín de Frutos and Yáñez Díaz represents another step in the transformation of laser data to CAD models, which are lighter and more compact and offer advantages over the 3D model, such as to complete occlusions and shadows or areas without information as well as project photo textures obtaining a greater visual appeal and a great similarity with the reality.
The authors of the awarded project have also done extensive photographic documentation of the entire Castle of Turégano complex as a virtual tour that allows us to cross it and learn the details, elements and views impossible to see at street.

A final year project in Topography

USAL presents his strategies for innovation in the “Club Innova”.

The chancellor highlight that “innnovación occurs through the transfer of knowledge and universities are the most important research centers in the country”.

USALThe University of Salamanca was the main protagonist of the last day of the second cycle of Innova Club, a forum for reflection and analysis focusing this time on the “important” role of the University to encourage innovation, a concept that is embodied “through the transfer of knowledge upon research performed at the centers, and universities are the most important research centers of the country”. These are words of the rector of the University of Salamanca, Daniel Hernández Ruipérez, responsible for opening the session with the mayor of Ávila, Miguel Ángel García Nieto, to begin a series of “interesting” papers on aspects of “how to understand innovation from the work of the university and the company, in their R&D departments», in addition to conferences to present cutting-edge projects coming out from Ávila in this context, both from the Polytechnic School and Education and Tourism.
The chancellor also argued for the establishment of “very fruitful discussion about the new production model to which we will arrive, the economy has to change, it will not be about a year or two, but fails to incorporate innovation into the production process”, Hernández Ruipérez said, for whom Ávila schools are “well-established” and “work well in both teaching and researching,” and the Polytechnic also in “technology transfer.”
It also referred to the Mayor of Ávila, Miguel Ángel García Nieto. “Innovation is closely linked to universities” that have always been “at the forefront of knowledge”, so continued the mayor, “we were interested to know where the experiences, ideas and projects of the University applied the concept of new methods for changing the production process are” because, he added, “a cycle is finished and we should put into start another with imagination”.
Speakers. With the presence of the principals of Ávila Schools, Sonsoles Sánchez Reyes (Education and Tourism), Miguel Ángel González Iglesias (Polytechnic) and Pilar González (Nursing), the event featured the participation of José Ángel Domínguez (Vice Chancellor for Teaching), Miguel Pérez (Vice Chancellor for Strategic Planning and Evaluation), José Luís Martínez Farrier (professor of Education and Tourism), Alberto Hernández (General Foundation of the University of Salamanca) and Diego González Aguilera (TIDOP Research Group of the University of Salamanca).


Unmanned flights to remote areas.

• The University of Salamanca designed a robotic helicopter that captures thermal images.
• It study the energy efficiency and structural damage to buildings.
• It also allows to reconstruct three-dimensional monuments.

UnmannedA multidisciplinary team from the University Of Salamanca (USAL), composed by surveyors, physicists, mathematicians and industrial and mining engineers are working from Ávila developing a research project with innovative applications in the world of engineering and heritage.
The project is a Robotic Air System (SAR) called ‘oktokopter’-eight arms or propellers and eight engines- that can fly without a pilot and, given its small size and remote operation, reach difficult corners to man, capturing images which can then be converted in 3D for different applications.
These include the inspection of large bridges, quarries and everything related with the heritage -elevations, profiles and sections-. To this we have to add the possibility, currently under development, for studies of energy efficiency in buildings from a thermal camera or measure water stress in plants. The latter case may be of interest to winegrowers.
This research project, which currently only has application in universities is being developed from the Information Technology for Heritage Documentation research group (TIDOP), led by a researcher at the University of Salamanca, Diego González Aguilera, doctor of the Engineering Geodesy and Cartography photogrammetry. With him, the industrial engineer Jesús Fernández Hernández, associate of USAL, and other younger researchers like Pablo Rodríguez Gonzálvez and Juan Mancera Taboada professor also found.
Both Fernández Hernández and González Aguilera agree that what is new is that this USAL team gives “one step” trying, through the research, to “add value to the plataform.”

Save costs and risks

This project promoted by the University of Salamanca, which is still under development, is an improvement from the point of view of research, but also in cost savings, as well as the possible reduction of accidents, being able to act in dangerous and inaccessible places.
Research efforts are being made in different directions. One is the development of tools and software to expand the operational and navigational capabilities of these platforms. Thus, it is intended to improve not only how to control the device, but to improve their positioning.
Another original feature is intended to include by the TIDOP group is derived from research into new low-cost sensors that enable the three-dimensional location of the 3D location with greater precision.

Damage in building and wineyards

This section is where we are studying the possibility of including a thermal camera that has the ability to detect other data almost imperceptible to the naked eye as structural damage and energy efficiency studies. This issue can be very interesting to detect the energy efficiency in buildings and even find heat loss in some of them, when this situation occurs.
The development of this application is being made in collaboration with the University of Castilla-La Mancha, like NDVI camera system that can measure water stress in plants. This system incorporated to the ‘oktokopter’ could be very interesting for the winemakers of the community and who would be able to monitor whether their vineyards need more water or, on the contrary, their abundance. This infrared camera would be used with different wavelength.

3D monuments

Another innovation that the USAL team intends to introduce to the aerial robotic system is “the implementation of 3D simulators that allow planning, study and simulation of 3-dimensional environments, facilitating flight plans and making the flight of these platforms semiautonomous “, says Diego González Aguilera.
Furthermore, this system allows the reconstruction of 3D environments, from aerial photographs taken from aerial robotic platforms and from the ground. So you can take photos for spherical 360-degree photos. The project is intended to include the possibility that, prior to the departure of the ship, design a flight plan to the virtual machine to do photos for use in the posterior and simulated reproduction of buildings, monuments, quarrying and infrastructure in 3D.


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Análisis termográfico de edificios


El uso de la termografía infrarroja comMapaEnergeticoo técnica sobradamente provada para la inspección de edificios y localización de patologías como fugas de aire, humedades, etc. Nos permite realizar un examen visual “in-situ” de calidad de los objetos de estudio gracias a la posibilidad de visualizar en tiempo real los resultados pudiendo detectar sin dificultad los desperfectos o elementos característicos de estos. Estas técnicas de medición cualitativa nos proporcionan la posibilidad de realizar inspecciones rápidas y eficaces sin contacto directo con el objeto y de forma no destructiva, lo que disminuye tanto el riesgo de incidentes para los operarios como los daños producidos en los propios objetos de estudio ocasionados por otras técnicas intrusivas. Además, también se ha demostrado la utilidad de la termografía infrarroja como técnica puramente de medida a través de su utilización para el cálculo de propiedades termofísicas de materiales tales como difusividad y transmitancia térmica.

En el caso de termografía cualitativa, las publicaciones existentes tratan de estudios realizados in-situ, principalmente en edificios históricos o elementos del patrimonio cultural, mientras que los estudios cualitativos se realizan, en la mayor parte de los casos, en laboratorios sobre muestras de tamaño limitado. En aquellos casos en los que se han realizado estudios termográficos cuantitativos sobre edificios in-situ, los valores de temperatura son empleados con el objetivo de obtener propiedades termofísicas (conductancia térmica) reales del cerramiento, sin embargo su distribución espacial no es considerada.

Conjugar ambas aplicaciones permitirá la automatización del cálculo de pérdidas de calor a partir de las temperaturas medidas con una cámara termográfica. De este modo, no solo se usa la termografía para representar el estado de la pared, sino que también se usan los valores de temperatura contenidos en la termografía para la extracción de parámetros métricos del edificio en estudio, por lo que la hibridación de la información termográfica con el material cartográfico de precisión permitiría extraer la geometría real del objeto de estudio con textura termográfica, pudiendo así realizar mediciones precisas de los elementos de interés directamente sobre el resultado obtenido.




Estudios como el publicado por EuroACE en 2010 colocan la mejora de la eficiencia energética en edificación en cabeza de las acciones necesarias para la reducción de emisiones de gases del efecto invernadero y gasto energético, así como para servir de empuje a la generación de empleo. Especial es el caso del parque de edificios ya construidos, la mayoría procedente de los años 1940-80, con normativa inexistente y recursos escasos. En ellos las obras de rehabilitación energética pueden suponer un ahorro de hasta el 75% en consumo de energía. En España existen 13 millones de viviendas susceptibles de intervención, cuya rehabilitación energética supondría una reducción de las emisiones del sector del 34% con respecto al año 2001.

Building thermographic analysis



The use of infraMapaEnergeticored thermography as a widely tested technique for building inspection and location of pathologies such as air leakage and moisture allows the performance of  quality “in-situ” visual examination of the objects under study due to the possibility of obtaining real-time results, being able to detect without difficulty damages or material characteristics. This qualitative measurement technique provides the capability of doing quick, effective and non-destructive inspection without direct contact with the object under study, decreasing the risk of incidents to operators and the damage of the objects comparing with other intrusive techniques. Furthermore, the utility of infrared thermography as a measurement technique has been proved by its use for the determination of the thermophysical properties of materials such as diffusivity and thermal transmittance.

In the qualitative approach, some authors have performed in-situ studies, mainly in historical buildings or cultural heritage elements, whereas quantitative studies are performed mainly in laboratories with limited size samples. In those cases where quantitative thermography studies were performed in-situ, temperature values were employed in order to obtain the real thermophysical properties (thermal conductance) of the building envelope, but their spatial distribution is not considered.

Combine both applications will enable the automation of the heat loss computation from the measured temperatures with a thermographic camera. Thus, the thermography is not only used to represent the state of the wall, but also temperature values represented on the thermography for extracting the metric parameters of the study object so the hybridization of the thermographic information with precise cartographic material would  allow to extract the actual geometry of the object of study with thermal texture, being able to make accurate measurements of the elements of interest directly on the obtained results.




Studies such as the one published by EuroACE in 2010, places improved energy efficiency in building construction at the top of the list of actions that need to be taken to reduce greenhouse gases and energy costs, in addition to acting as a stimulus to generate employment. In particular is the case of existing buildings stock, most of which dates back to the period 1940-80, constructed using non-existent standards and scarce resources. Here, energy refurbishment works could represent a saving of up to 75% in energy consumption. In Spain there are 13 million homes that could be the subject of intervention, where energy refurbishment could result in a reduction in sector emissions of 34% compared to 2001.


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Mobile Laser System (MLS) applied to urban tree inventory

In urbanized Western Europe trees are considered an important component of the built-up environment. This also means that there is an increasing demand for tree inventories. Laser mobile mapping systems provide an efficient and accurate way to sample the 3D road surrounding including notable roadside trees. In this research line, a processing chain aiming at the extraction of tree locations and tree sizes from laser mobile mapping data is reached.

  • Vegetation extraction


  • Tree parameter extraction



Such steps, in combination with code optimization are expected to be sufficient to reach the final goal of automatized estimation of features sampled by mobile mapping at a rate that matches the acquisition speed and at a quality that matches the result of a human operator.