- CSIC (Consejo Superior de Investigaciones Científicas-Spanish National Research Council), Institute of Heritage Sciences, Post-DocCSIC (Consejo Superior de Investigaciones Científicas-Spanish National Research Council), Institute of Heritage Sciences (Incipit), Post-DocUniversidade do Porto, Departamento de Geociências Ambiente e Ordenamento do Território, Department Memberadd
- Data Mining, Image Processing, Remote Sensing, Rural Development, Geoinformatics, Climatic Changes, and 23 moreLiDAR, Carbon Sequestration, Iberian Studies, LiDAR for Forestry, Airborne Laser Scanning, LiDAR for topographic mapping, Multispectral Imaging, LiDAR for Landscape Archaeology, Fire risk modelling, Land use and land cover, Archaeology, Landscape Archaeology, Aereal Archaeology, Geographic Information Systems (GIS), Remote sensing and GIS applications in Landscape Research, Geo-spatial analysis with GIS and GPS, 3D GIS, Environmental GIS, Computer Science, Remote sensing and GIS, Space, Archaeological Prospection, and Computer Applications & Quantitative Methods in Archaeology (CAA)edit
Roads have multiple effects on wildlife; amphibians are one of the groups more intensely affected by roadkills. Monitoring roadkills is expensive and time consuming. Automated mapping systems for detecting roadkills, based on robotic... more
Roads have multiple effects on wildlife; amphibians are one of the groups more intensely affected by roadkills.
Monitoring roadkills is expensive and time consuming. Automated mapping systems for detecting roadkills,
based on robotic computer vision techniques, are largely necessary. Amphibians can be recognised by a set of features
as shape, size, colouration, habitat and location. This species identification by using multiple features at the same time
is known as “jizz”. In a similar way to human vision, computer vision algorithms must incorporate a prioritisation
process when analysing the objects in an image. Our main goal here was to give a numerical priority sequence of
particular characteristics of roadkilled amphibians to improve the computing and learning process of algorithms. We
asked hundred and five amateur and professional herpetologists to answer a simple test of five sets with ten images
each of roadkilled amphibians, in order to determine which body parts or characteristics (body form, colour, and other
patterns) are used to identify correctly the species. Anura was the group most easily identified when it was roadkilled
and Caudata was the most difficult. The lower the taxonomic level of amphibian, the higher the difficulty of
identifying them, both in Anura and Caudata. Roadkilled amphibians in general and Anura group were mostly identified
by the Form, by the combination of Form and Colour, and finally by Colour. Caudata was identified mainly on
Form and Colour and on Colour. Computer vision algorithms must incorporate these combinations of features, avoiding
to work exclusively in one specific feature.
Monitoring roadkills is expensive and time consuming. Automated mapping systems for detecting roadkills,
based on robotic computer vision techniques, are largely necessary. Amphibians can be recognised by a set of features
as shape, size, colouration, habitat and location. This species identification by using multiple features at the same time
is known as “jizz”. In a similar way to human vision, computer vision algorithms must incorporate a prioritisation
process when analysing the objects in an image. Our main goal here was to give a numerical priority sequence of
particular characteristics of roadkilled amphibians to improve the computing and learning process of algorithms. We
asked hundred and five amateur and professional herpetologists to answer a simple test of five sets with ten images
each of roadkilled amphibians, in order to determine which body parts or characteristics (body form, colour, and other
patterns) are used to identify correctly the species. Anura was the group most easily identified when it was roadkilled
and Caudata was the most difficult. The lower the taxonomic level of amphibian, the higher the difficulty of
identifying them, both in Anura and Caudata. Roadkilled amphibians in general and Anura group were mostly identified
by the Form, by the combination of Form and Colour, and finally by Colour. Caudata was identified mainly on
Form and Colour and on Colour. Computer vision algorithms must incorporate these combinations of features, avoiding
to work exclusively in one specific feature.
Research Interests:
The Societas Europaea Herpetologica (SEH) decided in 2006 through its Mapping Committee to implement the New Atlas of Amphibians and Reptiles of Europe (NA2RE: http://na2re.ismai.pt) as a chorological database system. Initially designed... more
The Societas Europaea Herpetologica (SEH) decided in 2006 through its Mapping Committee to implement the New Atlas of Amphibians and Reptiles of Europe (NA2RE: http://na2re.ismai.pt) as a chorological database system. Initially designed to be a system of distributed databases, NA2RE quickly evolved to a Spatial Data Infrastructure, a system of geographically distributed systems. Each individual system has a national focus and is implemented in an online network, accessible through standard interfaces, thus allowing for interoperable communication and sharing of spatial-temporal data amongst one another. AWeb interface facilitates the access of the user to all participating data systems as if it were one single virtual integrated data-source. Upon user request, the Web interface searches all distributed data-sources for the requested data, integrating the answers in an always updated and interactive map. This infrastructure implements methods for fast actualisation of national observation records, as well as for the use of a common taxonomy and systematics. Using this
approach, data duplication is avoided, national systems are maintained in their own countries, and national organisations are responsible for their own data curation and management. The database could be built with different representation levels and resolution levels of data, and filtered according to species conservation matters. We present the first prototype of NA2RE, composed of the last data compilation performed by the SEH (Sillero et al., 2014). This system is implemented using only open source software: PostgreSQL database with PostGIS extension, Geoserver, and OpenLayers.
approach, data duplication is avoided, national systems are maintained in their own countries, and national organisations are responsible for their own data curation and management. The database could be built with different representation levels and resolution levels of data, and filtered according to species conservation matters. We present the first prototype of NA2RE, composed of the last data compilation performed by the SEH (Sillero et al., 2014). This system is implemented using only open source software: PostgreSQL database with PostGIS extension, Geoserver, and OpenLayers.
Research Interests:
The analysis of the spatial structure of animal communities requires spatial data to determine the distribution of individuals and their limiting factors. New technologies like very precise GPS as well as satellite imagery and aerial... more
The analysis of the spatial structure of animal communities requires spatial data to determine the distribution of individuals and their limiting factors. New technologies
like very precise GPS as well as satellite imagery and aerial photographs of very high spatial resolution are now available. Data from airborne LiDAR (Light Detection and
Ranging) sensors can provide digital models of ground and vegetation surfaces with pixel sizes of less than 1 m. We present the first study in terrestrial herpetology using
LiDAR data. We aim to identify the spatial patterns of a community of four species of lizards (Lacerta schreiberi, Timon lepidus, Podarcis bocagei, and P. hispanica), and to
determine how the habitat is influencing the distribution of the species spatially. The study area is located in Northern Portugal. The position of each lizard was recorded during 16 surveys of 1 h with a very precise GPS (error < 1 m). LiDAR data provided digital models of surface, terrain, and normalised height. From these data, we derived slope, ruggedness, orientation, and hill-shading variables. We applied spatial statistics to determine the spatial structure of the community. We computed Maxent ecological niche models to determine the importance of environmental variables. The community and its species presented a clustered distribution. We identified 14 clusters, composed
of 1–3 species. Species records showed two distribution patterns, with clusters associated with steep and flat areas. Cluster outliers had the same patterns. Juveniles and subadults were associated with areas of low quality, while sexes used space in similar ways. Maxent models identified suitable habitats across the study area for two species and in the flat areas for the other two species. LiDAR allowed us to understand the local distributions of a lizard community. Remotely sensed data and LiDAR are giving new insights into the study of species ecology. Images of higher spatial resolutions are necessary to map important factors such as refuges.
like very precise GPS as well as satellite imagery and aerial photographs of very high spatial resolution are now available. Data from airborne LiDAR (Light Detection and
Ranging) sensors can provide digital models of ground and vegetation surfaces with pixel sizes of less than 1 m. We present the first study in terrestrial herpetology using
LiDAR data. We aim to identify the spatial patterns of a community of four species of lizards (Lacerta schreiberi, Timon lepidus, Podarcis bocagei, and P. hispanica), and to
determine how the habitat is influencing the distribution of the species spatially. The study area is located in Northern Portugal. The position of each lizard was recorded during 16 surveys of 1 h with a very precise GPS (error < 1 m). LiDAR data provided digital models of surface, terrain, and normalised height. From these data, we derived slope, ruggedness, orientation, and hill-shading variables. We applied spatial statistics to determine the spatial structure of the community. We computed Maxent ecological niche models to determine the importance of environmental variables. The community and its species presented a clustered distribution. We identified 14 clusters, composed
of 1–3 species. Species records showed two distribution patterns, with clusters associated with steep and flat areas. Cluster outliers had the same patterns. Juveniles and subadults were associated with areas of low quality, while sexes used space in similar ways. Maxent models identified suitable habitats across the study area for two species and in the flat areas for the other two species. LiDAR allowed us to understand the local distributions of a lizard community. Remotely sensed data and LiDAR are giving new insights into the study of species ecology. Images of higher spatial resolutions are necessary to map important factors such as refuges.
Research Interests:
Research Interests:
Epigraphic inscriptions that present high level of surface degradation are usually difficult and tricky to read. Until now, most epigraphic readings have been accomplished by empiric procedures, supported by the visual and tactile... more
Epigraphic inscriptions that present high level of surface degradation are usually difficult and tricky to read. Until now, most epigraphic readings have been accomplished by empiric procedures, supported by the visual and tactile perception of the observer, which is naturally subjective, and, often, complemented by lightning techniques, like raking light, that enhance surface texture and detail by casting dramatic shadows on the surface. What if some of these heavily eroded inscriptions that are no longer perceived still keep traces of engravings? To address this challenge a simple and cost-effective method is presented, the Morphological Residual Model (M.R.M.). This method creates high contrast depictions of surface irregularities using 3D scanning data and morphological filtering algorithms. In most cases, the main epigraphic reading problems are overcome by this methodology as exemplified in the case-studies presented.
Research Interests:
The objective of this article is to present the possibilities and advantages of using the Morphological Residual Model (M.R.M.) technique as a new and accurate method for epigraphic reading, through the display of four paradigmatic case... more
The objective of this article is to present the possibilities and advantages of using the Morphological Residual Model (M.R.M.) technique as a new and accurate method for epigraphic reading, through the display of four paradigmatic case studies from Portugal. For each inscription, this new application allowed to recapture nearly the entire original engraved text, including the traces unseen to the human eye that were until now, impossible to recover through traditional epigraphic procedures. Each of these cases produced new readings that enlighten not only the text but also the context to which they were associated, pushing forward the epigraphic research.
Research Interests:
This article presents an airborne Light Detection and Ranging (LiDAR)-based method to extract interesting stand attributes for forest management in high-density Eucalyptus globulus Labill. plantations. An adaptive morphological filter... more
This article presents an airborne Light Detection and Ranging (LiDAR)-based method to extract interesting stand attributes for forest management in high-density Eucalyptus globulus Labill. plantations. An adaptive morphological filter (AMF) for classifying terrain LiDAR points in forested areas is used to classify LiDAR points; canopy cover (CC), number of LiDAR-detected trees per hectare (N LD) and individual tree height (h tree) were calculated using the canopy height model (CHM); and several statistics and metrics extracted from the CHM and the normalized height of the LiDAR data cloud (NHD) were incorporated into the linear and multiplicative models for estimating mean height (H m), dominant height (H d), mean diameter (d m), quadratic mean diameter (d g), number of stems per hectare (N), basal area (G) and volume (V). The height accuracy results of the LiDAR-derived digital terrain model (DTM), root mean square error (RMSE) = 0.303 m, revealed that the developed filter behaved well. The values of the RMSE for CC, N LD and h tree were 13.2%, 733.3 stems ha–1 and 1.91 m, respectively. The regressions explained 78% of the variance in ground-truth values for H m (RMSE = 1.33 m); 92% for H d (RMSE = 1.18 m); 71% for d m (RMSE = 1.68 cm); 73% for d g (RMSE = 1.66 cm); 49% for N (RMSE = 667 stems ha–1); 78% for G (RMSE = 5.30 m2 ha–1); and 81% for V (RMSE = 53.6 m3 ha–1).
Research Interests:
Human impact on the natural environment is an evident global fact. Natural, industrial and touristic areas coexist in a more than delicate balance. In Andalusia, in the south of Spain, the Regional Ministry for the Environment is... more
Human impact on the natural environment is an evident global fact. Natural, industrial and touristic areas coexist in a more than delicate balance. In Andalusia, in the south of Spain, the Regional Ministry for the Environment is responsible for the control and preservation of natural resources. This task bears a high cost in time and money. Remote sensing and the use of intelligent techniques are excellent tools to reduce such costs. This work explores the joint use of the lidar sensor, which provides a great quantity of information describing three dimensional space, and the application of intelligent techniques for rapid and efficient land use and land cover classification with the objective of differentiating urban land from natural ground close to protected areas of Huelva province. For this, seven types of land use and land cover have been studied for a riparian area next to the mouth of the rivers Tinto and Odiel, extracting 33 distinct features from the lidar point cloud. Subsequently, a supervised learning algorithm is applied to construct a model which, with a resolution of 4m^2, obtained relative precision between 71% and 100% and an average total precision of 85%.
Research Interests:
Research Interests:
Research Interests:
The use of techniques based on 3D point-clouds for modeling and documentation of cultural heritage and the mapping and survey of archaeological landscapes has evolved remarkably and it’s becoming of a widespread use. In the case of the... more
The use of techniques based on 3D point-clouds for modeling and documentation of cultural heritage and the mapping and survey of archaeological landscapes has evolved remarkably and it’s becoming of a widespread use. In the case of the mapping and prospection of mining landscapes, areas which are usually densely forested, the identification and documentation of archaeological features, coupled with its size and complexity, is still very problematic when relying on well-known methods such as photointerpretation or fieldwork.
The introduction of airborne laser scanning (ALS) or airborne Light Detection and Ranging (LiDAR) helped to overcome this problem because of its unique capability to penetrate vegetation canopies, allowing the documentation of the underneath topographic surface
and thus the identification of archaeological remains. The effectiveness of airborne LiDAR in detecting new archaeological sites and features and in improving the documentation of the already known is well proved, so ALS has completely revolutionized the area of archaeological survey. Given this, we present in this study some preliminary results related to the potential of airborne LiDAR to archaeological research of ancient mining landscapes.
The introduction of airborne laser scanning (ALS) or airborne Light Detection and Ranging (LiDAR) helped to overcome this problem because of its unique capability to penetrate vegetation canopies, allowing the documentation of the underneath topographic surface
and thus the identification of archaeological remains. The effectiveness of airborne LiDAR in detecting new archaeological sites and features and in improving the documentation of the already known is well proved, so ALS has completely revolutionized the area of archaeological survey. Given this, we present in this study some preliminary results related to the potential of airborne LiDAR to archaeological research of ancient mining landscapes.
Research Interests: Archaeology, Geoarchaeology, Landscape Archaeology, Cultural Heritage Recording, Documentation and Information Systems, Remote sensing and GIS applications in Landscape Research, and 9 moreArcheology of Roman mining, LiDAR for topographic mapping, Spatial analysis (Archaeology), 3D Laser Scanning (Archaeology), LiDAR for Landscape Archaeology, Roman Gold Mining, Technology and 3D Visualisation for Scientific Research in Archaeology, Roman Archaeology, and Airborne Laser Scanning (ALS)
The interpretation of archaeological features in LiDAR-derived Digital Elevation Models (DEM) is very dependent on visualization techniques. Different methods have been proposed to highlight microtopographies, from the “simple”... more
The interpretation of archaeological features in LiDAR-derived Digital Elevation Models (DEM) is very dependent on visualization techniques. Different methods have been proposed to highlight
microtopographies, from the “simple” hillshading, which can be easily computed in any GIS software, to more complex ones like Local Relief Models (LRMs). LRMs is a relevant visualization technique that allow us to discriminate between positive and negative microtopographies at a local scale, representing real changes in elevation rather than calculations based on steepness and direction of slope or exposure to light. In general terms, this procedure first calculates a trend DEM and then subtracts it from the original DEM, producing a LRM. In this study we present a Morphological Relief Model (MRM) which uses the quadric edge collapse decimation algorithm to produce a course mesh similar to the original model but free of small morphological details and thus improving the effects of smoothing filters that are normally used to calculate the trend DEM.
microtopographies, from the “simple” hillshading, which can be easily computed in any GIS software, to more complex ones like Local Relief Models (LRMs). LRMs is a relevant visualization technique that allow us to discriminate between positive and negative microtopographies at a local scale, representing real changes in elevation rather than calculations based on steepness and direction of slope or exposure to light. In general terms, this procedure first calculates a trend DEM and then subtracts it from the original DEM, producing a LRM. In this study we present a Morphological Relief Model (MRM) which uses the quadric edge collapse decimation algorithm to produce a course mesh similar to the original model but free of small morphological details and thus improving the effects of smoothing filters that are normally used to calculate the trend DEM.
Research Interests:
Herdade da Contenda (HC), located in Moura municipality, Beja district (Alentejo province) in the south of Portugal (southwestern Iberia Peninsula), is a national hunting area with 5270ha. The development of an integrated system that aims... more
Herdade da Contenda (HC), located in Moura municipality, Beja district (Alentejo province) in the south of Portugal (southwestern Iberia Peninsula), is a national hunting area with 5270ha. The development of an integrated system that aims to make the management of the natural and cultural heritage resources will be very useful for an effective management of this area. This integrated system should include the physical characterization of the territory, natural conservation, land use and land management themes, as well the cultural heritage resources. This paper presents a new tool for an integrated environmental management system of the HC, which aims to produce maps under a GIS open source environment (QGIS). The application is composed by a single button which opens a window. The window is composed by twelve menus (File, DRASTIC, Forest Fire Risk, Revised Universal Soil Loss Equation (RUSLE), Bioclimatic Index, Cultural Heritage, Fauna and Flora, Ortofoto, Normalizes Difference Vegetation Index (NDVI), Digital Elevation Model (DEM), Land Use Land Cover Cover (LULC) and Help. Several inputs are requires to generate these maps, e.g. DEM, geologic information, soil map, hydraulic conductivity information, LULC map, vulnerability and economic information, NDVI. Six buttons were added to the toolbar which allows to manipulate the information in the map canvas: Zoom in, Zoom out, Pan, Print/Layout and Clear. This integrated and open source GIS environment management system was developed for the HC area, but could be easily adapted to other natural or protected area. Despite the lack of data, the methodology presented fulfills the objectives.