Photogrammetric Methods Research Articles

Analysis and Comparison of Technologies of Survey of Buildings and Structures for the Purpose of Obtaining a 3D Model

In the framework of the preservation of historical and cultural heritage, it is important to provide for the possibility of preserving and recreating a virtual historical model of the city, first of all - architectural structures. To obtain reliable spatial data about the location and configuration of the building, tacheometric survey, laser scanning and photogrammetric methods are usually used. In this paper, an experiment was conducted to obtain a three-dimensional model of the building using all the above methods. As a result, the following conclusions were made: all technologies allow us to obtain a 3D model of the property; in time field and office work, the advantages are laser scanning technology and photogrammetric methods with UAVS; in terms of efficiency, it is possible to distinguish aerial photography from UAVS, since it is relatively inexpensive compared to laser systems; in accuracy, tacheometric survey will have an advantage, since measurements are made at a specific point, and its coordinates are calculated, but this advantage can only be for buildings that are simple in geometry, for complex architectural forms and complex technical structures, the use of an electronic tachymeter is impractical

Contrasting whisker growth dynamics within the phocid lineage

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 634:231-236 (2020) - DOI: https://doi.org/10.3354/meps13204 NOTE Contrasting whisker growth dynamics within the phocid lineage Elizabeth A. McHuron1,3,*, Terrie Williams1, Daniel P. Costa1, Colleen Reichmuth2 1Department of Ecology and Evolution, University of California Santa Cruz, Santa Cruz, CA 95060, USA 2Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95060, USA 3Present address: Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, WA 98115, USA *Corresponding author: emchuron@uw.edu ABSTRACT: The use of biochemical analyses of whiskers to address ecological and physiological questions requires an understanding of whisker growth dynamics. To expand comparative data for phocid seals, we report fine-scale growth patterns, retention times, and temporal patterns of whisker loss for 3 captive seals using direct and photogrammetric methods. The ringed seal Pusa hispida, bearded seal Erignathus barbatus, and Hawaiian monk seal Neomonachus schauinslandi all showed rapid regrowth following whisker loss, with maximum growth rates of 0.15 to 0.20 cm d-1. After this initial growth period, tissue deposition rates contrasted between the smallest species—the ringed seal—and the other 2 species. Ringed seal whiskers exhibited an asymptotic growth pattern typical of other phocids, whereas growth of bearded and monk seal whiskers continued at a slow, linear rate until shedding. The ringed seal had a seasonal pattern of whisker loss that coincided with the timing of the annual pelage molt, whereas there was no temporal pattern of whisker loss for the other 2 species. The rapid-to-slow growth of bearded and monk seal whiskers is unique within the phocid lineage, along with the presence of smooth rather than undulated whiskers in these species. In light of phylogenetic differences in growth and shedding patterns, extrapolation of whisker growth to related species requires careful consideration. KEY WORDS: Vibrissae · Bearded seal · Ringed seal · Monk seal · Biochemical analyses Full text in pdf format Supplementary material PreviousCite this article as: McHuron EA, Williams T, Costa DP, Reichmuth C (2020) Contrasting whisker growth dynamics within the phocid lineage. Mar Ecol Prog Ser 634:231-236. https://doi.org/10.3354/meps13204 Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 634. Online publication date: January 23, 2020 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2020 Inter-Research.

Variation in soil surface roughness under different land uses in a small watershed on the Loess Plateau, China

Soil surface roughness (SSR) significantly influences hydrological and erosion processes under different conditions. Land use and its adjustment may greatly influence SSR via altering near soil surface characteristics and tillage operations, but few studies have been performed to quantify their effects on soil surface roughness. This study was conducted to investigate the variation in soil surface roughness under different land use types, and identify the main influencing factors contributing to these changes in a small watershed on the Loess Plateau, China. Eighteen sites were selected from five typical land use types (cropland, grassland, shrub land, orchard, and woodland) to measure random roughness (RR) by a photogrammetric method. The results showed that random roughness was greatly affected by land use types, plant species, and tillage operations. The mean RR under different land use types ranged from 9.47 to 10.06 mm. Woodland had the maximum RR, followed by cropland, shrub land, orchard, and grassland. For a given land use type, RR differed significantly between different plant species. The variation in random roughness was greatly influenced by the changes in near soil surface characteristics and tillage operations induced by land use adjustment. For the testing sites without tillage operations, RR increased linearly with soil median grain size, sand content, organic matter content, plant litter coverage, litter thickness, and litter density, while it decreased linearly with soil cohesion, silt content, and clay content. For the testing sites with tillage operations, RR was dominated by tillage operations. These results are helpful to understand the potential effects of vegetation restoration on hydrological and erosion processes on hillslopes in arid and semi-arid regions.

A systematic review on ear anthropometry and its industrial design applications

AbstractErgonomics is extensively studied to provide a scientific understanding of humans’ physical and cognitive use of products and workplaces. Ergonomics of the external ear is crucial for the industrial design of various ear‐related products. For this review, 50 articles regarding ear anthropometry and its applications in product design that met determined inclusion criteria were selected after searching four databases, including Scopus, Web of Science, PubMed, and Science Direct. Previous anthropometric information acquired with traditional measurement, photogrammetric method, and three dimensional (3D) anthropometric techniques (photogrammetry, magnetic resonance imaging, computerized tomography, 3D scanning, and ear impression). Those studies demonstrated that demographic factors, including age, ethnicity, gender, and ear symmetry, should be considered when designing for specific markets. Ear sizes kept growth throughout the entire lifetime. Results also showed that males had larger ear sizes than females in most populations. Most of linear, area, and ratio dimensions showed a good symmetry between left and right ears, while angular dimensions tended to be nonsymmetric. Differences in anthropometric findings existed among Asian, Western, and African populations. Hence, there is a need to establish more universal anthropometric databases for different ethnicities to meet the development of product form and function. Furthermore, fit and comfort perception was important to be examined for product design, which can be studied through questionnaire on comfort perception, analysis online comments of consumers, and virtual fit analysis. With a comprehensive presentation of literature, future research opportunities were inspired from the perspective of industrial design.

The Convent of Santa Teresa de Jesús in Havana: analysis, consolidation and restoration for the New Museum of Sacred Art

Thanks to an inter-university agreement between the University of Florence and the University College San Geronimo in La Habana, on the occasion of the Master’s thesis in Architecture of Florence it was possible to approach the case study of the Convent of Santa Teresa del Jesús in La Havana (Cuba).The Convent, built in the early 1700s for the Order of the Discalced Carmelites, maintained its function until 1827 when, following the transfer of the nuns, it was first converted into Casas de Vecindad and subsequently into Ciutadela (1960) compromising consistently the integrity of the factory. Since 1998 it has become part of the list of risk sites “2000 World Monuments Fund” [WMF (2000)] and since 2005 it has undergone a careful and long process of restoration by the Oficina del Historiador da La Habana (OHCH). [WMF, (2020)]The work focused first on the constriction of a cognitive framework of the building aimed at a correct assessment of the historical evolutionary and metrological characteristics of the local construction system adopted. Then the geometric and cracking survey of a portion of the Convent corresponding to the first cloister, the oldest, was carried out by means of a direct and photogrammetric method, which showed some structural anomalies, highlighting a progressive subsidence in correspondence with the south-east corner of the cloister.According to the information provided by the relevant campaign, some tests were made on the foundations of the portion affected by the settlement. The analyzes carried out on the specimens have evidenced soils with a low cohesive capacity, sensitive to charges in humidity with consequent variation in their volume. In the same way, the analyzes on degradation pathologies have evidenced a sensitivity to the variation in the capillary humidity amount, as well as to the multiple anthropic alterations; furthermore, the analysis of the crack pattern has revealed a widespread and complex structural degradation leading to manifestation of collapse mechanisms of the second and third types in the intrinsically weakest points.Based on the results obtained in the cognitive phase, a conservative restoration hypothesis was formulated limited to some parts not affected by substantial static degradation, instead recommending the reconstruction of the remaining parts in compliance with traditional construction materials and techniques or for anastylosis where necessary. A proposal was also made to consolidate the structure by strengthening the existing foundations through the technique of underpinning. The project proposal was formulated by adopting a participatory approach based on local planning guidelines.In order to enhance this place, a proposal was made to re-functionalize it by proposing different uses but always in line with the protection needs of the cultural heritage itself, so that it could be returned to the city and its inhabitants in the hope that it could become, in the future, a hub for both tourism and the community. To this end, the project involved the combination of public and museum areas, transforming the complex into a multifunctional cultural center including the New Museum of Sacred Art of the City with related service, an urban park and a recreation center for childhood and third age with the aim of promoting and developing cultural service and programs that may involve the resident community, helping to make the historical, architectural and artistic heritage known and enjoyed.

Selected examples of historical cartography

In World War II, the Battle of Monte Cassino (also called the Battle of Rome) was a breakthrough moment of the Italian campaign. The Battle of Monte Cassino, which was remarkably vicious and ruthless, lasted nearly five months. During the entire Italian campaign, which ran from 3 September 1943 to 2 May 1945, the Allies lost nearly 312,000 soldiers and Germans suffered about 435,000 killed and injured, i.e. an average of 1,233 people per day for both sides. The most fierce fights took place on the Gustav Line: Germans, Italians, Americans, French, British, Indians, New Zealanders, Poles, Canadians and South Africans lost about 200,000 soldiers within 129 days. The 2nd Polish Corps alone had 924 dead, 2930 injured and 345 missing. During the recognition of the site and the preparation of the assaults, soldiers of the 12th Geographical Company of the 2nd Polish Corps drew, alongside maps, many perspective sketches of hills and structures from several observation posts. The authors attempted to analyse selected sketches, in terms of their geometric parameters and compatibility with a map made in 1944, based on aerial photographs. Some of these sketches are not perspective drawings but panoramic (mapped on cylindrical or spherical surface), with specified angular graduation and distances. Probably, they were to be used for artillery fire – which is proven by their precision. The art of the terrain’s details is also noteworthy. On the other hand, photogrammetric observations, unlike geodesic ones, are not made directly on the measured object, but indirectly on properly taken photographs. They are called measuring photos or photograms. The basic requirement for measuring photos is their fidelity with a central projection (which, in view of the imperfections of image extraction techniques, is only its closest mathematical model). After taking pictures, the actual dimensions and shape of the area or object recorded in the pictures are determined by awareness of the conditions under which these photos were taken (shooting distance and camera type). For these reasons, photogrammetric methods have been used in archaeology, architecture and preservation of monuments, astronomy, ballistics, construction, geology, mining, hydrology, forensics, forestry, medicine, automotive and shipbuilding industries, and especially in surveying and cartography.

Association of Upper Quarter Posture with Depression, Anxiety, and Level of Physical Activity in Sixth Grade Elementary School Students of Karaj City, Iran

Background: Postural abnormalities are prevalent among elementary school students. The aim of this study was to investigate the association of the upper quarter posture with depression, anxiety and level of physical activity in elementary school students of Karaj. Methods: In this cross-sectional study, 346 sixth grade students were randomly selected from 10 elementary schools. Levels of physical activity, anxiety, and depression were measured and the data were collected employing International Physical Activity Questionnaire-Short form (IPAQ-SF), Revised Children’s Manifest Anxiety Scale (RCMAS), and Children’s Depression Inventory (CDI), respectively. Photogrammetric method and a flexible ruler were used to assess the students’ posture. Pearson correlation test and linear regression model at the confidence level of 95% (P<0.05) was utilized to analyze the data. Results: There was a significant relation between depression and the craniovertebral angle (P=0.003); physical activity levels were also correlated with the sagittal head angle (P=0.012), and kyphosis (P=0.012). Conclusions: Certain postural abnormalities were associated with physical activity and psychological problems. Therefore, preventive actions are of great necessity to decrease postural and psychological problems.

МЕТОДЫ И ТЕХНОЛОГИИ АЭРОФОТОСЪЕМКИ И НАЗЕМНОЙ ФОТОГРАММЕТРИЧЕСКОЙ СЪЕМКИ ПРИ АРХЕОЛОГИЧЕСКИХ ИЗЫСКАНИЯХ

This article we consider methods and technologies of unmanned aerial surveying and close-range photogrammetric survey as applied for archeological research. We summed up the practical experience of the specialists of the Moscow State University of Geodesy and Cartography (MIIGAiK), obtained with the participation in the Bosporus archaeological expedition of the State Historical Museum on the Taman Peninsula in 2018–20. During the 3 expeditions, 18 archaeological sites were surveyed by aerial methods using UAV Geoscan 101 Geodesy and UAS DJI Phantom 4 Pro. In addition to aerial surveying, the Canon 30D digital camera with 50 mm and 14 mm focal lengths was used for groundbased, close-range photogrammetric surveys of archaeological sites. Some sites were surveyed many times during different periods of archaeological research. At all surveyed archaeological sites using photogrammetric processing methods at the Agisoft Metashape software we received survey documents (orthophoto, digital terrain models, 3D models). For some artifacts, three-dimensional metric models have been obtained using digital photogrammetry methods. Various methods of aerial surveying were used to study archaeological sites. The article gives recommendations on optimization of photography process in order to obtain reliable and informative documents for archaeological excavations. Comparison and analysis of aerial and close-range survey data was performed by the QGIS geographic information system. The information obtained using geo-information technologies will improve the quality and reliability of forecasts and hypotheses in archaeological studies.

Фотограмметрические и дистанционные методы создания и обновления топографических карт

Фотограмметрические и дистанционные методы создания и обновления топографических карт

Posture of adolescent volleyball players – a two-year study

Summary Study aim: The aim of this study was to assess and compare the posture of male and female adolescent volleyball players and non-training individuals over a 2-year period. Material and methods: The study group comprised 32 volleyball players and 30 non-athlete peers. Posture was assessed with a photogrammetric method based on the moiré phenomenon. Participants were examined 3 times at the ages of 14, 15 and 16 years. Training experience of the studied volleyball players at the time of the 1st measurement was less than 5 months. Results: In volleyball players greater asymmetry in the pelvis position was noted (rotation to the right). The right scapula was more outlying than the left, and the right shoulder was more elevated than the left. Volleyball training did not result in sagittal spinal curvatures. Male non-athlete participants exhibited a significant increase in thoracic kyphosis and a decrease in lumbar lordosis over a two-year period. Conclusion: Volleyball training affects the alignment of the pelvis, shoulder girdle and scapulae. The study revealed a number of differences in spinal curvatures between male volleyball players and non-athletes which could be associated with growth velocity and differences in body height.

Innovative photogrammetric methods for monitoring agrolandscapes nanorelief

The object of the study is the materials of aerial photography obtained with the application of an unmanned aerial vehicle (UAV) DJI Phantom 3 Advanced and processed by Agisoft PhotoScan Professional Edition software. The objective of the present research is to study the feasibility of the data obtained by innovative photogrammetric methods for monitoring and analyzing the agrolandscapes nanorelief as well as for the design of agrolandscapes in adaptive landscape farming, to identify the possibilities of assessing the occurrence of erosion and make a forecast of their development in the study area using photographic plans. In the course of the work, methods and means of obtaining aerial photographs of a site in the Voronezh region were considered. The altitude map and orthophotomap resulting from image processing were analysed. It has been revealed that such digital models make it possible to study and analyze the state of the surface of agrolandscapes up to the smallest forms of nanorelief both visually and with the application of mathematical characteristics. However, deficiencies in the accuracy of the obtained plans along the edges of the shooting area were noted and the methods for solving the problem of inacuracy were proposed.

Research into harmful effect of underground mining operations on the state of buildings and structures located in the displacement area

An urgent task of both the mine surveyor service and the entire mining sector is to develop and implement in production the remote digital methods for monitoring the deformations of buildings and structures, which are located in areas influenced by underground mining operations. When developing a new methodology for determining the buildings and structures deformations, special attention is paid to improving the photogrammetric method. The study is aimed at determining the optimal conditions for digital imaging of buildings and structures in order to obtain the deformation values with the required accuracy. Based on the results of experimental work on the simultaneous different-scale images processing, the accuracy of determining the planimetric coordinates and heights of the studied points is much higher compared to the previously used methodology, in which digital models of an object are plotted from images obtained by a single camera lens, that is, with the same metric characteristics. The use of high degree of detail and fragmentation of large-scale images, as well as a significantly smaller number of small-scale images, covering the surveyed object, improve the accuracy of determining the position of points, which in turn affects the reduction of the error in combining the models.

Разработка модифицированной системы управления БПЛА для оперативного мониторинга состояния природных и техногенных территориальных комплексов

This paper discusses the issues of creating an aerial survey complex based on an unmanned aerial vehicle. The analysis of the efficiency of using aerial survey complexes based on unmanned aerial vehicles for operational monitoring of the state of natural and man-made territorial complexes is carried out. The paper considers the process of developing a modified control system for unmanned aerial vehicles, as well as the subsequent photogrammetric processing of aerial photographs. The quality of electronic units installed on unmanned aerial vehicles has been determined. The created modified control system for unmanned aerial vehicles and geographically referenced terrain orthophotomaps obtained by photogrammetric methods make it possible to classify the captured objects, perform their vectorization and provide each object with semantic information. The developed modified aerial survey complex will allow real-time monitoring of the state of natural and man-made territorial complexes based on remote sensing data from UAVs.

PHOTOGRAMMETRIC METHOD OF FORENSIC PHOTOGRAPHY Artem Kovalenk

The article is devoted to defining the essence and directions of application of the photogrammetric method of forensic photography in criminal proceedings. It is determined that the photogrammetric method of forensic photography is to photograph objects according to special rules in order to further measure them on the obtained images. It is determined that the photogrammetric method of judicial photography consists in photographing objects according to special rules in order to perform their further measurements using the obtained images. The method of measuring objects using a single image is called monophotogrammetric and is known in the theory of forensic photography as measuring (scale) method; using a pair of images is called stereophotogrammetric (known as stereoscopic); measurement with more than two images is a polyphotogrammetric method. As a result of polyphotogrammetric fixation of an object with the help of a serial digital camera and computer image processing, it is possible to obtain its high-quality geometrically accurate textured three-dimensional model. Objects of different sizes, from micro-objects, to entire buildings or areas, interiors can be scanned with polyphotogrammetric method. The 3D model of the scanned object reconstructed as a result of polyphotogrammetric photography and software processing can be saved in a number of conventional formats in electronic form, viewed and researched using special software. The rules and algorithm of polyphotogrammetric scaning are given, the process of reconstruction of 3D model on the basis of received images is described. The advantages of the researched method of forensic photography are its non-invasiveness, clarity and accuracy of the obtained models, wide possibilities of their use and research.

Two Camera 3D Time Series Reconstruction of a Mesh Subjected to Differential Excitation

The present study proposes a novel bio-inspired scheme for the 3D time series reconstruction of a Mesh. The key motivation of this study is to develop a cost effective and accessible system without compromising capabilities for the fundamental understanding in complicated external stimuli-induced vibration of a Mesh. A bio-inspired algorithm traces along the strands of the mesh to match a known control point to the next keypoint until the entire surface is matched for the critical reconstruction at the first frame/timestep. The match is then disseminated to the subsequent frames steps via digital image correlation and photogrammetric methods applied to effectively recover the time series response of the dynamic surface. This study offers significant and quantitative insight into the vibration and fluctuation of the entire excited surface. A 160mm×160mm mesh fluctuation is successfully re-constructing with a sampling density of approximately 1600 points at 24 frames per second. The proof-of-concept experiment was able to detect the undulation of mesh under an in-phase and an out-of-phase excitation, which result in the reconstruction of the point cloud with a 0.38mm error, as well as the frequency and phase angle accuracy attainments of about 99.1% and 86.0%, respectively. In short, the current reconstruction scheme may provide insights into the control and response of a piezoelectric mesh.

Estimating tree stem diameters and volume from smartphone photogrammetric point clouds

AbstractMethods for the three-dimensional (3D) reconstruction of forest trees have been suggested for data from active and passive sensors. Laser scanner technologies have become popular in the last few years, despite their high costs. Since the improvements in photogrammetric algorithms (e.g. structure from motion—SfM), photographs have become a new low-cost source of 3D point clouds. In this study, we use images captured by a smartphone camera to calculate dense point clouds of a forest plot using SfM. Eighteen point clouds were produced by changing the densification parameters (Image scale, Point density, Minimum number of matches) in order to investigate their influence on the quality of the point clouds produced. In order to estimate diameter at breast height (d.b.h.) and stem volumes, we developed an automatic method that extracts the stems from the point cloud and then models them with cylinders. The results show that Image scale is the most influential parameter in terms of identifying and extracting trees from the point clouds. The best performance with cylinder modelling from point clouds compared to field data had an RMSE of 1.9 cm and 0.094 m3, for d.b.h. and volume, respectively. Thus, for forest management and planning purposes, it is possible to use our photogrammetric and modelling methods to measure d.b.h., stem volume and possibly other forest inventory metrics, rapidly and without felling trees. The proposed methodology significantly reduces working time in the field, using ‘non-professional’ instruments and automating estimates of dendrometric parameters.

Changes in sediment connectivity following glacial debuttressing in an Alpine valley system

Increasing air temperature and declining winter snowfalls are resulting in rapid glacier recession and the expansion of proglacial margins in Alpine regions. Such margins include substantial debris accumulations (e.g. frontal/lateral moraine ridges; till-covered and steep valley sidewalls) which may be unstable due to glacial debuttressing. Rainfall, snowmelt and ice melt out may then cause mass movements. Here, we quantify the decadal-scale erosion and deposition patterns and changes in connectivity for two valley sidewall geomorphological systems following retreat of the Glacier d'Otemma, Switzerland. We apply archival digital photogrammetric methods to the period 1964 to 2009 to determine high resolution digital elevation models. These were differenced to calculate patterns of erosion and deposition and to quantify the evolution of sediment connectivity. We found that gully headward erosion (rates between ca. −10.6 mm/year and −1002.1 mm/year) was the main geomorphological process during glacier thinning but increasing depositional rates downslope of the gullies (ca. +21.3 to +298.5 mm/year) were recorded in the following years associated with significant alluvial fan growth at the slope base. While gullying enhanced connectivity by removing glacially conditioned sediment transfer buffers, so connecting side-slopes to upstream sediment sinks (the upslope contributing area between 1964 and 2009 increased by +73.8% and +195.1% in each subsystem), alluvial fans reduced the rates of sediment transfer to the rapidly enlarging glacial forefields. The detail of these responses is conditioned by three generic processes: (1) the wider geomorphic setting – here, the presence of a moraine bastion as a primary part of the sediment cascade strongly influenced gully morphology evolution and the likely length of the paraglacial period length; (2) the thickness of sediment left by the retreating glacier which controlled the influence of bedrock topographic buffers on connectivity; and (3) the extent to which diffusive drainage systems develop in response to the deposition at the hillslope base, which tend to disconnect sediment flux. Post-glacially, gully development has a self-limiting effect on sediment connectivity in that while gullying increases sediment connectivity, the eroded sediment leads to deposition on the alluvial plain that reduces sediment connectivity.

The use of small-Unmanned Aerial Systems for high resolution analysis for intertidal wetland restoration schemes

Coastal and estuarine wetlands provide a range of important ecosystem services, but are currently being damaged and degraded due to human activities, reduced sediment supply and sea level rise. Managed realignment (MR) is one approach used to compensate for the loss of intertidal habitat, however saltmarshes in MR sites have been recognised to have lower biodiversity than natural environments. This has been associated with differences in the physical functioning including the sediment structure, reduced hydraulic connectivity, and lower topographic variability such as the abundance of intertidal creek networks. Intertidal morphology, including creek networks, play an important role in supporting and regulating saltmarsh environments through the supply of sediment, nutrients and water, and in draining intertidal marshes. However, there is a lack of empirical data on the formation and evolution of topographic features and variability in saltmarsh environments. This is likely to be due to creek networks in natural marshes already being in a state of quasi-equilibrium, making MR sites an ideal environment to investigate creek development. However, traditional remote sensing techniques (such as LiDAR) tend to be relatively expensive, infrequent and at a coarse resolution meaning small, but important (cm-scale), changes are often missed. This study advances the ability to detect these small scale changes by demonstrating the suitability and potential applications of using the emerging photogrammetric method Structure-from-Motion (SfM) on images taken using a small-Unmanned Aerial System (sUAS). Three surveys from a rapidly changing, near-breach site were taken at the Medmerry Managed Realignment Site in July 2016, September 2017 and July 2018. A suitable degree of confidence was found between the modelled surface and independent check points (vertical root-mean-square-errors of 0.0245, 0.0704 and 0.1571 for 2016, 2017 and 2018 respectively). DSMs of Difference (DoD) analysis was performed to evaluate elevation change, with areas experiencing up to 85 cm of accretion between 2016 and 2018. However, when considering the error associated with both surveys, between 2016 and 2017, only 34.39% of the survey area experienced change above the level of detection (LoD). In contrast, 76.97% experienced change greater than the LoD between 2017 and 2018. Stream order analysis classified the creek networks into five orders in 2016 and four orders in 2017 and 2018, with 2016 having a higher abundance (291 in 2016 compared to 117 (2017) and 112 (2018)) and density (0.44 m/m2 in 2016 compared to 0.27 m/m2 in both 2017 and 2018) of creek networks. These results provide an innovative high resolution insight into the evolution of restored intertidal wetlands, and suggest that SfM analysis of images taken using a sUAS can be a useful tool with the potential to be incorporated into studies of MR and natural saltmarsh sites. sUAS analysis can, therefore, advance the management of these environments to ensure the provision of ecosystem services and to protect against future anthropogenic activity, sea level rise and climate change.

3D MODELING OF ROMAN BRIDGE BY THE INTEGRATION OF TERRESTRIAL AND UAV PHOTOGRAMMETRIC SURVEY FOR STRUCTURAL ANALYSIS PURPOSE

Abstract. The 3D survey of the masonry bridges is rather complex and may require the integration of terrestrial and aerial surveys. In fact, in order to perform the survey of the superstructure of a bridge, the photogrammetric survey may be realized by the use UAV (Unmanned Aerial Vehicle) since it allows acquiring all the details of the upper part of the bridge. Indeed, especially the extreme lateral parts of the bridge cannot be performed through a traditional terrestrial survey. In addition, the UAV photogrammetry allows speeding up and optimizing work. As regards the terrestrial survey, instead, it has the advantage of being able to use highly performing optics and cameras (high resolution of the sensor, stabilized optics, etc.). However, these types of sensors are quite heavy and, in general, could not be mounted on an aerial platform on commercial and low-cost drones. In any case, beyond the payload of common commercial drones at low cost, there is also the problem that the digital cameras mounted on the UAV platforms cannot observe the arches of the bridge from the bottom upwards by low-cost tools. Therefore, a simple way to build a unique 3D model consists in the integration of terrestrial and aerial surveys; in this way, using a suitable procedure, sensor and software based on the Structure from Motion (SfM) and Multi View Stereo (MVS) approaches, it was possible to build detailed, precise and textured three-dimensional models of structures, such as the buildings, historical artefact, bridges etc.In this paper, a case study concerning the construction of a three-dimensional model according a photogrammetric method of a Roman bridge is discussed. In particular, the bridge taken under investigation, belong to the Cultural Heritage, is called “San Cono” and is located in south of Italy. After built the 3D model of masonry bridge (3D point cloud and 3D mesh), it was identified a special procedure that allowed to obtain the model of the bridge suitable for a structural analysis within of dedicate software.

Photogrammetric Bathymetry for the Canadian Arctic

Remote sensing is becoming common in the estimation of bathymetry for navigational charting through a process known as Satellite Derived Bathymetry (SDB). Most SDB techniques currently used by hydrographic offices employ an empirical approach, requiring the use of in-situ data to calibrate a relationship between spectral information and coincident depths. This article reports on a multi-site test of an alternative SDB method which uses photogrammetry to extract depths from stereo WorldView-2 imagery. In areas with heterogeneous seafloors, the empirical approach faces difficulties in establishing the relationship between colour and depth, while the photogrammetric approach uses the contrasting seafloor features for triangulation. Additionally, the photogrammetric method may be applied in areas lacking previous survey data. Five study areas in Nunavut, Canada were selected to test the robustness of the method in different environments and under different imaging conditions. Study areas were (with resulting RMSE/Bias given in metres) Coral Harbour (0.84/−0.47), Cambridge Bay (1.16/−0.15), Queen Maud Gulf (0.97/0.06), Arviat (0.99/−0.009), and Frobisher Bay, where extraction largely failed due to environmental conditions. Accuracies demonstrated here are similar to those seen using the empirical approach, suggesting that these two methods may be used in conjunction, each applied to regions where they are better suited.