This paper deals with the application of Unmanned Aerial Vehicles (UAV) techniques and high resolution photogrammetry to study the evolution of a landslide affecting olive groves. The last decade has seen an extensive use of UAV, a technology in clear progression in many environmental applications like landslide research. The methodology starts with the execution of UAV flights to acquire very high resolution images, which are oriented and georeferenced by means of aerial triangulation, bundle block adjustment and Structure from Motion (SfM) techniques, using ground control points (GCPs) as well as points transferred between flights. After Digital Surface Models (DSMs) and orthophotographs were obtained, both differential models and displacements at DSM check points between campaigns were calculated. Vertical and horizontal displacements in the range of a few decimeters to several meters were respectively measured. Finally, as the landslide occurred in an olive grove which presents a regular pattern, a semi-automatic approach to identifying and determining horizontal displacements between olive tree centroids was also developed. In conclusion, the study shows that landslide monitoring can be carried out with the required accuracy-in the order of 0.10 to 0.15 m-by means of the combination of non-invasive techniques such as UAV, photogrammetry and geographic information system (GIS).

ABSTRACT:This paper presents a methodology for slope instability monitoring using photogrammetric techniques with very high resolution images from an unmanned aerial vehicle (UAV). An unstable area located in La Guardia (Jaen, Southern Spain), where an active mud flow has been identified, was surveyed between 2012 and 2014 by means of four UAV flights. These surveys were also compared with those data from a previous conventional aerial photogrammetric and LiDAR survey. The UAV was an octocopter equipped with GPS, inertial units and a mirrorless interchangeable-lens camera. The flight height was 90 m, which allowed covering an area of about 250 x 100 m with a ground pixel size of 2.5 cm. The orientation of the UAV flights were carried out by means of ground control points measured with GPS, but the previous aerial photogrammetric/LiDAR flight was oriented by means of direct georeferencing with in flight positioning and inertial data, although some common ground control points were used to adjust all flights in the same reference system. The DSMs of all surveys were obtained by automatic image correlation and then the differential models were calculated, allowing estimate changes in the surface. At the same time, orthophotos were obtained so horizontal and vertical displacements between relevant points were registered. Significant displacements were observed between some campaigns (some centimeters on the vertical and meters on the horizontal). Finally, we have analyzed the relation of displacements to rainfalls in recent years in the area, finding a significant temporal correlation between the two variables.

Abstract:In this work a detailed analysis of the temporal evolution of the Almegíjar landslide is presented. It is a rock slide located in the Alpujarras region (Granada, Spain) that has developed over the last 30 years. Six datasets and photogrammetric flights corresponding to the years 1956, 1984, 1992, 2001, 2008, and 2010 were surveyed. The more recent flight of 2010 combined an aerial digital camera and a LiDAR sensor and was oriented by means of in-flight data and tie points. This 2010 flight allowed for the generation of a reliable and high-precision Digital Terrain Model (DTM). The other flights were oriented using second-order ground control points transferred from the 2010 flight, and the corresponding DTMs were prepared by automatic matching and subsequent editing from the stereoscopic models. After comparing the DTMs of different dates, it has been observed that the landslide was triggered after 1984 and since then has evolved in an irregular pattern with periods of variable activity. On average, the ground surface dropped more than 8 m in depleted zones and rose nearly 4 m in the accumulation zones, with a velocity catalogued as very slow (about 15-30 cm/year) over a time span corresponding to a degree VIII of diachroneity. The total volume of the mobilized mass of this large contemporary slide was about 300 × 10 3 m 3 .

In the present work, the case of the Cármenes del Mar resort (Granada, Spain) is shown. It can be considered one of the most extreme examples on the Mediterranean coast of severe pathologies associated with urban development on coastal landslides. The resort, with 416 dwellings, was partially built on a deepseated landslide which affects a soft formation composed of dark graphite schists. In November 2015, the City Council officially declared a state of emergency in the resort and 24 dwellings have already been evacuated. We have used two remote sensing techniques to monitor the landslide with the aim of identifying and measuring a wide range of displacements rates (from mm/year to m/year): (1) PSInSAR, exploiting 25 ENVISAT SAR images acquired from May 2003 to December 2009, and (2) photogrammetry, considering the output from two Unmanned Aerial Vehicle (UAV) flights made in June 2015 and January 2016 and the outdated photos from a conventional flight in 2008. The relationship between the geology of the site, data from PS deformation measurements, building displacements, rainfall and damage observed and their temporal occurrence allows a better understanding of the landslide kinematics and both the spatial and temporal evolution of the instability. Results indicate building displacements of up to 1.92 m in 8 years, a clear lithological control in the spatial distribution of damage and a close relationship between the most damaging events and water recharge episodes (rainy events and leaks from swimming pools and the water supply network). This work emphasises the need to incorporate geohazards into urban planning, including policies to predict, prepare for and prevent this type of phenomenon.

At present, airborne laser scanner systems are one of the most frequent methods used to obtain digital terrain elevation models. While having the advantage of direct measurement on the object, the point cloud obtained has the need for classification of their points according to its belonging to the ground. This need for classification of raw data has led to appearance of multiple filters focused LiDAR classification information. According this approach, this paper presents a classification method that combines LiDAR data segmentation techniques and progressive densification to carry out the location of the points belonging to the ground. The proposed methodology is tested on several datasets with different terrain characteristics and data availability. In all case, we analyze the advantages and disadvantages that have been obtained compared with the individual techniques application and, in a special way, the benefits derived from the integration of both classification techniques. In order to provide a more comprehensive quality control of the classification process, the obtained results have been compared with the derived from a manual procedure, which is used as reference classification. The results are also compared with other automatic classification methodologies included in some commercial software packages, highly contrasted by users for LiDAR data treatment.

Abstract:This paper describes the methodology used to capture information from a religious sculpture. The study also shows the results obtained in using free software and fusion of data from laser scanner and photographs. In this sense, one of the problems that can occur when Heritage documentation is made, is the impossibility of move the object of study from other places with appropriates environment conditions to capture data. This problem is especially important in the case of sculptures found upright with certain height, where many upper portions are hidden by the inability to locate safely locate the instruments. This paper show a case of study with this problem and provides the solution to capture data in cenital position with laser scanner. Finally, the overall results are showed and some considerations in terms of conservation and diffusion of the cultural heritage. Key words: cultural heritage, 3D documentation, instrumentation, data fusion Resumen:En este trabajo se presenta la metodología empleada para la captura de información de una imagen cofrade objeto de estudio, así como los resultados obtenidos en su modelado haciendo uso de software libre y la fusión de datos procedentes de escáner láser y de tomas fotográficas. En este sentido, uno de los problemas que pueden existir a la hora de la documentación tridimensional del patrimonio cultural es la imposibilidad de su desplazamiento a zonas de trabajo donde las condiciones y entorno de trabajo sean los idóneos para llevar a cabo la captura de los datos. Este problema es especialmente importante en el caso de imágenes o esculturas que se encuentran en posición vertical con cierta altura, donde muchas partes superiores se quedan ocultas por la imposibilidad de situar de manera segura el instrumental que suele ser pesado, sobre el objeto a digitalizar. En este trabajo, se presenta un caso de estudio donde aparece esta problemática y la solución aportada para realizar capturas de tipo cenital con láser escáner. Finalmente, se muestran los resultados generales obtenidos, así como algunas consideraciones de los mismos en cuanto a los resultados en cuanto a la conservación como la difusión del objeto modelizado.Palabras clave: patrimonio cultural, documentación 3D, instrumentación, fusión de datos IntroducciónEl modelado tridimensional se podría describir como la descripción numérica de una superficie a partir de un conjunto de puntos medidos por diferentes técnicas. De esta forma, a partir de datos discretos, se idealiza una superficie matemática a partir de distintos algoritmos de reconstrucción superficial, como son los métodos de Poisson, Ball Pivoting o el VCG (Berger et al. 2014).En cuanto a las principales técnicas para la obtención de esta información discreta del objeto, podemos diferenciar dos grandes grupos. En un primer lugar, las técnicas fotogramétricas, las cuales basan la obtención de la geometría del objeto de estudio en la reconstrucción de la posición de la fotografías y en la detección de puntos homólogos, de manera que se reconstruye s...

ABSTRACT:The province of Jaen (Southern Spain) has one of the largest concentrations of medieval fortresses of all Europe. Moreover ancient Iberian settlements located in oppida (fortified villages) and dated at VI-IV BC also are outstanding examples of historical heritage landmarks in the region. Most of these places are being restored or under documentation analysis to prevent their progressive deterioration. These places have several geometric characteristics in common, such as isolated locations, elongated shapes, largemedium size objects (in the order of tens to few hundred of meters), architectural features with vertical development (such as masonry or rammed earth walls, towers, gates, battlements, etc) or without it (walls, buildings or paths layouts at ground level). The object size, the required level of details and accuracy (of the order of some few cm) and both vertical and horizontal features imply that present UAS techniques can be advantageously used with respect to conventional aerial and terrestrial photogrammetric techniques. Vertical stereoscopic and oblique convergent UAS photogrammetric networks combined with processing techniques based on Structure from Motion (SfM) algorithms allow detailed low cost 2D/3D products. The proper selection of the UAS, camera, image acquisition mode (stop and/or cruising), the network and the processing software will determine the quality of final products and their usefulness in metric documentation, 3D modelization or museology. The efficiency of the use of UAS has been analyzed in several selected examples in Jaen (Burgalimar and Berrueco castles, Xth and XIIIth centuries, respectively, and the Iberian Puente Tablas oppidum, Vth-IVth centuries BC).

The cultural heritage plays a very important role in the Smart management of an area, and geospatial technologies are a perfect tool for the heritage knowledge, management and analysis. Photogrammetry, UAV systems and geographic information systems, can help in cataloguing the cultural heritage of a city. The main turistic value for Alcalá la Real, is the Monumental Group of the Fortress of La Mota and their related monuments.As the principal objetive of the Project, an analysis and the calculation of the optimal location of the watchtower network is made. To achieve this, on the one hand photogrammetry technics are used to get the geometric information of the studied area. On the other hand, photogrammetry through UAV systems is used to obtain the 3D model of one of the watchtowers, which is better preserved than others. Finally, programming tools are applied over GIS for the analysis and calculation of the optimal location of this watchtower network.