Hasil untuk "Geodesy"

E. S. Ince, F. Barthelmes, S. Reißland et al.

Abstract. The International Centre for Global Earth Models (ICGEM, http://icgem.gfz-potsdam.de/, last access: 6 May 2019) hosted at the GFZ German Research Centre for Geosciences (GFZ) is one of the five services coordinated by the International Gravity Field Service (IGFS) of the International Association of Geodesy (IAG). The goal of the ICGEM service is to provide the scientific community with a state-of-the-art archive of static and temporal global gravity field models of the Earth, and develop and operate interactive calculation and visualization services of gravity field functionals on user-defined grids or at a list of particular points via its website. ICGEM offers the largest collection of global gravity field models, including those from the 1960s to the 1990s, as well as the most recent ones, which have been developed using data from dedicated satellite gravity missions, CHAMP, GRACE, GOCE, advanced processing methodologies, and additional data sources such as satellite altimetry and terrestrial gravity. The global gravity field models have been collected from different institutions at international level and after a validation process made publicly available in a standardized format with DOI numbers assigned through GFZ Data Services. The development and maintenance of such a unique platform is crucial for the scientific community in geodesy, geophysics, oceanography, and climate research. In this article, we present the development history and future plans of ICGEM and its current products and essential services. We present the ICGEM's data by means of Earth's static, temporal, and topographic gravity field models as well as the gravity field models of other celestial bodies together with examples produced by the ICGEM's calculation and 3-D visualization services and give an insight into how the ICGEM service can additionally contribute to the needs of research and society.

Zechao Bai, Yuxiao Qin, Yanping Wang et al.

Monitoring the structural deformation of bridge with high precision during the operation process is crucial for assessing its health. This study proposes a practical strategy for jointly measuring multi-scale periodic dynamic deformation in bridges using both spaceborne and ground-based Interferometric Synthetic Aperture Radar (InSAR) technologies. The proposed strategy involves extracting seasonal periodic deformation by applying thermal expansion components with spaceborne Persistent Scatterer InSAR (PS-InSAR) and capturing daily periodic deformation using a two-stage atmospheric phase screen compensation ground-based InSAR method. This study focuses on a double-tower cable-stayed and rigid frame system bridge to investigate the spatiotemporal evolution of bridge multi-scale periodic dynamic deformation patterns. The monitoring results indicate that the geometric state and deformation pattern of the bridge remained stable, exhibiting significant seasonal and daily dynamic deformations that were either positively or negatively correlated with temperature changes. Seasonal periodic deformation captured by spaceborne InSAR showed maximum displacements near expansion joints, while tower deformation remained constrained within ±5 mm. Daily periodic deformation captured by ground-based InSAR revealed significant displacements at the bridge tower top, contrasting with minimal deformation of ±2 mm near fixed bearings. These deformations exhibited significant correlations with temperature changes. Both the deformation trend and magnitude confirmed to the computational results of the bridge structure design.

Fatemeh Parto Dezfooli, Mohammad Javad Valadan Zoej, Fahimeh Youssefi et al.

Zoonotic Cutaneous Leishmaniasis (ZCL) is a vector-borne disease (VBD) characterized by distinct spatiotemporal patterns. Accurate evaluation of ZCL risk patterns necessitates the utilization of comprehensive epidemiological and ecological data. This study proposes a hybrid model that integrates the advantages of geographic information systems (GIS) for trend analysis, remote sensing (RS) for environmental data extraction, and machine learning (ML) for ZCL risk assessment in Ilam Province, Iran. Utilizing data from 2014 to 2019, spatial and temporal patterns are investigated using Moran’s I, Getis-Ord Gi* statistics, and the Mann-Kendall (MK) test, while high-risk ZCL maps are generated through Extreme Gradient Boosting (XGBoost) and Random Forest (RF) models. The proposed model harnesses high-precision disease and environmental geospatial monitoring to address limitations of previous systems through robust, data-driven insights. The results reveal significant patterns, with a Moran’s I statistic of 0.68 (p < 0.01) and MK values of –2.254 for annual data (p = 0.024) and 3.340 for monthly data (p = 0.001). Temporal analysis indicates a declining trend, with peak incidence observed in late fall and early winter. Consequently, due to the incubation period, the critical infection period occurs during summer. The risk maps demonstrate high levels of accuracy (area under the curve of 0.96 for RF and 0.98 for XGBoost), pinpointing high-risk areas in the western and southern hot deserts and low-risk regions in the northeastern mountainous areas. Moreover, there is an increasing trend in high-risk zones, corresponding to rising temperatures across different cities and seasons. These findings highlight a significant relationship between ZCL spread and temperature-related factors, offering valuable insights for future research.

Wenke Zheng, Zhaofeng Du, Xiaomin Zhou et al.

Land subsidence significantly impacts the accuracy of the National Elevation Datum in China. In order to solve this issue, a dynamic and economical way was proposed to update the National Elevation Datum with the assistance of InSAR in the North China Plain, which served as the research area. Moreover, the GNSS result was used to correct the InSAR result for the vertical deformation field, which has a relatively unified deformation reference. By integrating the vertical deformation field with the national elevation control point, an analysis and evaluation of changes in the National Elevation Datum were conducted. In addition, a regional remeasurement scheme was formulated to achieve dynamic updates and maintenance of the National Elevation Datum on a regional scale. Through data acquisition and processing, we successfully improved reliability within the main subsidence areas for future use. As a result, updating the elevation values utilize a regional update method, and a dynamic and economical technical process to update the National Elevation Datum is shown in the study.

Ning Zhou, Guo Zhang, Chunyang Zhu et al.

With the expansion of human activities into mountainous regions, jungles, deserts, rural roads, and off-road terrains, there is an increasing demand for reliable navigation and location services in wild unstructured environments. Unlike urban environments, where established methodologies exist for constructing navigation maps, roadless unstructured environments lack comprehensive frameworks for navigation map construction. The conventional waypoint-based structures, which are well-suited to urban environments, are often ill-suited to the expansive and unstructured nature of field regions. Moreover, the absence of predefined user paths necessitates a fundamentally different approach to map construction. To address this challenge, we propose a novel method for generating navigation maps in unstructured roadless environment. New methodology leverages remote sensing as input for environmental perception, translating user traversability into geographical parameters and constructing a navigation mesh as a computational map. Compared with existing methods, the new method can adapt to large-scale unstructured environments. To validate the proposed method, reliability sampling tests and operational experiments were conducted on traversable area delineation and the navigation map generation. The experimental results indicate an 84% accuracy in traversable area analysis, with the constructed navigation map effectively supporting positioning and path planning while significantly reducing computational complexity in large-scale path planning tasks. The navigation mesh generated through this method effectively enhances the implementation of navigation and positioning services in off-road and roadless environments. The proposed method facilitates the construction of navigation maps capable of delivering navigation and localization services without requiring human presence in the target area.

Salmanian Milad, Rastbood Asghar, Hossainali Masoud Mashhadi

This study delves into slip distribution on the North Tabriz Fault (NTF), a critical aspect of seismic hazard analysis due to its proximity to the Tabriz metropolis. The study operates within a uniform elastic half-space, maintaining constant values for fault geometry and regional rheological parameters throughout the research. To calculate strain boundary conditions, permanent and periodic global positioning system (GPS) data from the northwest region were utilized. The fault was constrained perpendicularly while allowing tangential movement, facilitating the determination of its annual slip rate using the boundary element method, with the Okada analytical model serving as the fundamental solution. The findings underscore the intricate relationship between the fault’s slip rate and boundary conditions, revealing a predominant right-lateral strike-slip motion. The study offers two slip rate assessments, obtained through earthquake focal mechanisms and GPS velocity data, yielding values of 5 and 5.5 mm/year{\rm{mm}}/{\rm{year}}, respectively. Importantly, the alignment of these calculated slip rates with paleo-seismological data underscores the credibility of the results generated via the boundary element method, distinguishing it as a reliable approach when compared to other numerical and analytical techniques. This research provides valuable insights into the behavior and slip dynamics of the NTF, which is pivotal for assessing seismic risks.

Kosmas Pavlopoulos, Daniel Moraetis, Michael Foumelis et al.

Abstract Eustatic sea level changes and vertical tectonic movements are producing uplifted paleoshorelines. Along subduction zones, uplifted terraces are used to study fault activities and, overall, allow to interpret the tectonic history of plate convergence. Northeastern Oman is experiencing plate convergence following the late Cretaceous obduction of the Semail Ophiolite. Post‐obduction shallow‐marine carbonates have been uplifted to different elevations from 133 to >2,000 m. The present study employs a multidisciplinary approach to elucidate the variability in relief and to introduce a geodynamic model that extends beyond the temporal constraints imposed by the late Quaternary age of the sediments found on the uplifted terraces. Stratigraphic and fault analyses produced a post‐obductional geodynamic model to advance the existing regional models in the framework of the subduction of the Arabian Plate in the Makran Zone. In addition, we rely on imaging geodesy, geomorphology and dating to explain the late Quaternary uplift scenario. Overall, analyses of geomorphology, stratigraphy, and fault patterns reveal spatially heterogeneous post‐late Cretaceous uplift in the region. Compartmentalization by major faults created individual blocks and relief variability. Within the timeframe of marine terrace formation (late Quaternary), we also observed spatially varied displacements. Ground displacements by Interferometric Synthetic Aperture Radar document an ongoing spatial heterogenous uplift at approximately 1.3 mm/a. Finally, temporal variability was evident during the late Quaternary by unusually high late Pleistocene (<40 ka) uplift rates averaging ≥2 mm/a in younger terraces, while for older terraces (>40 ka) the uplift rate is distinctly lower (<1 mm/a).

Atınç Pırtı

The European Commission (EC) originally proposed ideas for a European Galileo satellite navigation system in 1999. A four-phase development is planned, involving investment from both the public and commercial sectors. Galileo is intended for both public and government use; the system is administered and operated by civil administration. Galileo will consist of a constellation of 30 satellites, a number of globally situated ground stations, and a ground control and monitoring system – all of which are quite similar to the structure, format, and layout of GPS. This document discusses an experiment at the project site that used the static approach to integrate GPS, GLONASS, GALILEO, Beidou, and QZSS signals. This research analyses the possible precision of GPS-only and GPS/GLONASS/GALILEO/Beidou/QZSS. These results suggest that combining a GPS system with GALILEO, GLONASS Beidou, and QZSS is preferable for surveying purposes. Integrating GPS/GLONASS/GALILEO/Beidou/QZSS static measurements in the study region with 0–120 millimetre accuracy looks to be possible in three days.

Ruoming Zhai, Jingui Zou, Yifeng He et al.

Point-based networks have been widely used in the semantic segmentation of point clouds owing to the powerful 3D convolution neural network (CNN) baseline. Most of the current methods resort to intermediate regular representations for reorganizing the structure of point clouds for 3D CNN networks, but they may neglect the inherent contextual information. In our work, we focus on capturing discriminative features with the interactive attention mechanism and propose a novel method consisting of the regional simplified dual attention network and global graph convolution network. Firstly, we cluster homogeneous points into superpoints and construct a superpoint graph to effectively reduce the computation complexity and greatly maintain spatial topological relations among superpoints. Secondly, we integrate cross-position attention and cross-channel attention into a single head attention module and design a novel interactive attention gating (IAG)-based multilayer perceptron (MLP) network (IAG–MLP), which is utilized for the expansion of the receptive field and augmentation of discriminative features in local embeddings. Afterwards, the combination of stacked IAG–MLP blocks and the global graph convolution network, called IAGC, is proposed to learn high-dimensional local features in superpoints and progressively update these local embeddings with the recurrent neural network (RNN) network. Our proposed framework is evaluated on three indoor open benchmarks, and the 6-fold cross-validation results of the S3DIS dataset show that the local IAG–MLP network brings about 1% and 6.1% improvement in overall accuracy (OA) and mean class intersection-over-union (mIoU), respectively, compared with the PointNet local network. Furthermore, our IAGC network outperforms other CNN-based approaches in the ScanNet V2 dataset by at least 7.9% in mIoU. The experimental results indicate that the proposed method can better capture contextual information and achieve competitive overall performance in the semantic segmentation task.

Satrio Muhammad Alif, Erlangga Ibrahim Fattah, Munawar Kholil

65 km Semangko Fault is part of southern segments of Sumatran Fault Zone (SFZ) which is complex corresponds to the transition from the strike-slip regime of the SFZ to the normal faulting tectonics of the Sunda Strait. The recent publication showed branches of Semangko Fault: West Semangko Fault (WSF) and East Semangko Fault (ESF). This study estimated geodetic slip rate and locking depth of ESF using Global Positioning System (GPS) time series data from 2007 to 2019 from all available GPS sites. GPS velocities refer to Sundaland Plate were used to estimate the fault parameters of the WSF and ESF simultaneously. Non-uniformity of velocity direction shows the complexities of Semangko Fault possibly caused by the contribution of all faults around ESF. An ESF geodetic slip rate, which is 12.5 ± 2 mm/yr was lower than WSF, which is 16.5 ± 2 mm/yr. It is consistent with the rigid block nature of the SFZ system as northern segment slip rates have similar value. Small slip rates are possibly leading to lower generated seismic moment than the major segment of SFZ.

M. Mohammadi, F. Tabib Mahmoudi, M. Hedayatifard

Automatic vehicle recognition has an important role for many applications such as supervision, traffic management and rescue tasks. The ability of online supervision on the distribution of vehicles in urban environments prevents traffic, which in turn reduces air pollution and noise. However, this is extremely challenging due to the small size of vehicles, their different types and orientations, and the visual similarity to some other objects in very high resolution images. In this paper, an automatic vehicle recognition algorithm is proposed based on very high spatial resolution aerial images. In the first step of the proposed method, by generating the image pyramid, the candidate regions of the vehicles are recognized. Then, performing reverse pyramid, decision level fusion of the vehicle candidates and the land use/cover classification results of the original image resolution are performed in order to modify recognized vehicle regions. For evaluating the performance of the proposed method in this study, Ultracam aerial imagery with spatial resolution of 11&thinsp;cm and 3 spectral bands have been used. Comparing the obtained vehicle recognition results from the proposed decision fusion algorithm with some manually selected vehicle regions confirm the accuracy of about %80. Moreover, the %78.87 and 0.71 are respectively the values for overall accuracy and Kappa coefficient of the obtained land use/cover classification map from decision fusion algorithm.

Karol Daliga, Zygmunt Kurałowicz

The measurement of a chimney axis is an engineering geodesy task. These measurements allow to assess the technical condition of chimneys and are usually carried out for reinforced concrete chimneys. When measuring high chimneys, the main problem may be the need to go a long distance to take a measurement. The surface of the chimney can also be problematic because it can absorb so much light from the range finder that total station reflectorless measurement or laser scanning will not be possible or will be affected by significant error. Chimneys made of stainless steel are also used today. They are not as high as reinforced concrete chimneys, but measuring them using reflectorless total stations or laser scanning can also be problematic. Problems arise from the reflective surface of these chimneys. The article presents a comparison of measurement results of a stainless steel chimney fragment obtained from total station measurement and laser scanning. Similarities and differences in the obtained axis of this chimney fragment are presented.

Nedjeljko Frančula, Miljenko Lapaine

The aspect of a projection is the position of the axis of the projection in relation to the axis of rotation of the Earth’s sphere. The aspect may be normal, transverse, or oblique.

E. Oniga, C. Chirilă, F. Stătescu

Nowadays, Unmanned Aerial Systems (UASs) are a wide used technique for acquisition in order to create buildings 3D models, providing the acquisition of a high number of images at very high resolution or video sequences, in a very short time. Since low-cost UASs are preferred, the accuracy of a building 3D model created using this platforms must be evaluated. To achieve results, the dean's office building from the Faculty of “Hydrotechnical Engineering, Geodesy and Environmental Engineering” of Iasi, Romania, has been chosen, which is a complex shape building with the roof formed of two hyperbolic paraboloids. Seven points were placed on the ground around the building, three of them being used as GCPs, while the remaining four as Check points (CPs) for accuracy assessment. Additionally, the coordinates of 10 natural CPs representing the building characteristic points were measured with a Leica TCR 405 total station. The building 3D model was created as a point cloud which was automatically generated based on digital images acquired with the low-cost UASs, using the image matching algorithm and different software like 3DF Zephyr, Visual SfM, PhotoModeler Scanner and Drone2Map for ArcGIS. Except for the PhotoModeler Scanner software, the interior and exterior orientation parameters were determined simultaneously by solving a self-calibrating bundle adjustment. Based on the UAS point clouds, automatically generated by using the above mentioned software and GNSS data respectively, the parameters of the east side hyperbolic paraboloid were calculated using the least squares method and a statistical blunder detection. Then, in order to assess the accuracy of the building 3D model, several comparisons were made for the facades and the roof with reference data, considered with minimum errors: TLS mesh for the facades and GNSS mesh for the roof. Finally, the front facade of the building was created in 3D based on its characteristic points using the PhotoModeler Scanner software, resulting a CAD (Computer Aided Design) model. The results showed the high potential of using low-cost UASs for building 3D model creation and if the building 3D model is created based on its characteristic points the accuracy is significantly improved.

Yuanjin Pan, Wen-Bin Shen, Cheinway Hwang et al.

Surface vertical deformation includes the Earth’s elastic response to mass loading on or near the surface. Continuous Global Positioning System (CGPS) stations record such deformations to estimate seasonal and secular mass changes. We used 41 CGPS stations to construct a time series of coordinate changes, which are decomposed by empirical orthogonal functions (EOFs), in northeastern Tibet. The first common mode shows clear seasonal changes, indicating seasonal surface mass re-distribution around northeastern Tibet. The GPS-derived result is then assessed in terms of the mass changes observed in northeastern Tibet. The GPS-derived common mode vertical change and the stacked Gravity Recovery and Climate Experiment (GRACE) mass change are consistent, suggesting that the seasonal surface mass variation is caused by changes in the hydrological, atmospheric and non-tidal ocean loads. The annual peak-to-peak surface mass changes derived from GPS and GRACE results show seasonal oscillations in mass loads, and the corresponding amplitudes are between 3 and 35 mm/year. There is an apparent gradually increasing gravity between 0.1 and 0.9 μGal/year in northeast Tibet. Crustal vertical deformation is determined after eliminating the surface load effects from GRACE, without considering Glacial Isostatic Adjustment (GIA) contribution. It reveals crustal uplift around northeastern Tibet from the corrected GPS vertical velocity. The unusual uplift of the Longmen Shan fault indicates tectonically sophisticated processes in northeastern Tibet.

M. Mustafa Berber, D. Uğur Şanli

After geodetic networks (e.g., horizontal control, leveling, GNSS etc.) are established, they are measured and point coordinates are estimated by the method of Least Squares. If one or more observations are burdened with errors, these contaminated observations affect the other good observations and may produce incorrect estimates of the parameters. Thus, these contaminated observations should be detected and corrected. Generally, in practice, they are removed and the network is readjusted. To detect the outliers among the observations statistical tests are performed. Yet, reliability measures should be accompanied to statistical tests to find out more about the ability of error detection and the effects of errors on the solutions. Now it is possible that reliability measures can be calculated for the cases of single or multiple outliers. In this paper, a GNSS network is analyzed using reliability measures in both cases. The results show that in the case of multiple outliers reliability measures worsen.

Miroslav Malinović

The work deals with the architecture of the Franciscan convent and church of Saint Peter and Paul in Tuzla – a complex built during the 80s of the XX century, according to а project done by one of the most prominent domestic architects, the academician Zlatko Ugljen. Although the Franciscan convent existed in Tuzla even earlier, the site of the contemporary complex is entirely new, which allowed Ugljen to produce а new language in architecture and the identity of the place, unburdened by the historical legacy.After the introductory historical discussion, the work addresses several proposed solutions, and afterwards the developed project, as well as its transformation and changes throughout the time, up until nowadays. Besides that, short review on the interior design and artistic decoration of the complex is presented. Work also gives short insight on the important Ugljen’s projects, with the aim of correct positioning of this project within the rich author’s opus. 

M. Shangguan, M. Bender, M. Ramatschi et al.

Water vapor plays an important role in meteorological applications; GeoForschungsZentrum (GFZ) therefore developed a tomographic system to derive 3-D distributions of the tropospheric water vapor above Germany using GPS data from about 300 ground stations. Input data for the tomographic reconstructions are generated by the Earth Parameter and Orbit determination System (EPOS) software of the GFZ, which provides zenith total delay (ZTD), integrated water vapor (IWV) and slant total delay (STD) data operationally with a temporal resolution of 2.5 min (STD) and 15 min (ZTD, IWV). The water vapor distribution in the atmosphere is derived by tomographic reconstruction techniques. The quality of the solution is dependent on many factors such as the spatial coverage of the atmosphere with slant paths, the spatial distribution of their intersections and the accuracy of the input observations. Independent observations are required to validate the tomographic reconstructions and to get precise information on the accuracy of the derived 3-D water vapor fields. To determine the quality of the GPS tomography, more than 8000 vertical water vapor profiles at 13 German radiosonde stations were used for the comparison. The radiosondes were launched twice a day (at 00:00 UTC and 12:00 UTC) in 2007. In this paper, parameters of the entire profiles such as the wet refractivity, and the zenith wet delay have been compared. Before the validation the temporal and spatial distribution of the slant paths, serving as a basis for tomographic reconstruction, as well as their angular distribution were studied. The mean wet refractivity differences between tomography and radiosonde data for all points vary from −1.3 to 0.3, and the root mean square is within the range of 6.5–9. About 32% of 6803 profiles match well, 23% match badly and 45% are difficult to classify as they match only in parts.

Žilvinas Stankevičius, Aušra Kalantaitė

The paper treats experiment of LIDAR points filtering. The goal of filtering is to remove redundancy points for map sheets printing and designing tasks. General aim is the precision of filtering data for designing tasks. Result of experiment is the chosen parameters of filters. Functions of smoothing, thinning, preservation of important points and combination of these functions were applied in analysis process. To compare results collected from different parameters of functions, the method of digging capacity was used. The values of parameters, that fulfill conditions, the calculation precision of digging capacity using in practice were defined. Article in Lithuanian LIDAR žemės paviršiaus taškų masyvo supaprastinimo algoritmų parametrų parinkimas Santrauka. Straipsnyje pristatomas LIDAR taškų filtravimo eksperimentas. Filtravimo tikslas – panaikinti perteklinius spaudinių planams sudaryti ir projektuoti taškus. Siekiama sumažinti LIDAR duomenų apimtį išlaikant filtruotais duomenimis paremtų sprendimų tikslumą ir patikimumą. Tyrimų rezultatas – parinkti tinkami filtrų parametrai. Tyrimų eigoje buvo taikomos taškų glodinimo, retinimo, būdingųjų taškų išsaugojimo funkcijos. Taip pat tirtas kombinuotasis filtrų taikymo būdas. Skirtingų parametrų dydžių taikymo rezultatai įvertinti tūrių palyginimo metodu. Leistinasis tūrių skirtumas po filtravimo funkcijos pritaikymo nustatytas remiantis praktikoje taikomos Žemės darbų tūrių skaičiavimo metodikos tikslumu. Reikšminiai žodžiai: LIDAR, skaitmeninis paviršiaus modelis, filtravimas.

M. Y. Yang, W. Förstner, D. Chai

The classification of building facade images is a challenging problem that receives a great deal of attention in the photogrammetry community. Image classification is critically dependent on the features. In this paper, we perform an empirical feature evaluation task for building facade images. Feature sets we choose are basic features, color features, histogram features, Peucker features, texture features, and SIFT features. We present an approach for region-wise labeling using an efficient randomized decision forest classifier and local features. We conduct our experiments with building facade image classification on the eTRIMS dataset, where our focus is the object classes <i>building</i>, <i>car</i>, <i>door</i>, <i>pavement</i>, <i>road</i>, <i>sky</i>, <i>vegetation</i>, and <i>window</i>.