Research

29 pages, 27134 KiB

Open AccessArticle

Topographic Base Maps from Remote Sensing Data for Engineering Geomorphological Modelling: An Application on Coastal Mediterranean Landscape

by Maurizio Barbarella, Albina Cuomo, Alessandro Di Benedetto, Margherita Fiani and Domenico Guida

Geosciences 2019, 9(12), 500; https://doi.org/10.3390/geosciences9120500 - 27 Nov 2019

Cited by 11 | Viewed by 4816

Abstract

Coastal landscapes are one of the most changeable areas of the earth’s surface. Given this spatial complexity and temporal variability, the construction of reference maps useful for geo-engineering is a challenge. In order to improve the performance of geomorphic models, reliable multiscale and [...] Read more.

Coastal landscapes are one of the most changeable areas of the earth’s surface. Given this spatial complexity and temporal variability, the construction of reference maps useful for geo-engineering is a challenge. In order to improve the performance of geomorphic models, reliable multiscale and multi-temporal base maps and Digital Elevation Models (DEM) are needed. The work presented in this paper addresses this issue using an inter-geo-disciplinary approach to optimize the processing of multisource and multi-temporal data and DEMs by using field surveys, conceptual model, and analytical computation on a test area. The data acquired with two surveying techniques were analyzed and compared: Aerial Laser Scanning (ALS) and photogrammetry from stereo pairs of High-Resolution Satellite Images (HRSI). To assess the reliability of the DEMs produced from point clouds, the residuals between the point cloud and the interpolated filtered surface were identified and analyzed statistically. In addition to the contour maps, some feature maps such as slope, planar, and profile curvature maps were produced and analyzed. The frequency distribution of the slope and curvature values were compared with the diffusion, advection, and stream power model, revealing a good agreement with the past and present geomorphic processes acting on the different parts of the study area. Moreover, the integrated geomatics–geomorphic analysis of the outliers’ map showed a good correspondence (more than 75%) between the identified outliers and some specific geomorphological features, such as micro-landforms, which are significant for erosive and gravity-driven mechanisms. The different distribution of the above singularities by different data sources allowed us to attribute their spatial model to the temporal variation of the topography and, consequently, to the geomorphic changes, rather than to the different accuracy. For monitoring purposes and risk mitigation activities, the methodology adopted seems to meet the requirements to make a digital mapping of the coast analyzed, characterized by a rapid evolution of the surface, and can be extended to other stretches of coast with similar characteristics. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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17 pages, 19564 KiB

Open AccessArticle

Non-Linear Analysis of Inter-Story Pounding between Wood-Framed Buildings during Ground Motion

by Wojciech Migda, Marcin Szczepański, Natalia Lasowicz, Anna Jakubczyk-Gałczyńska and Robert Jankowski

Geosciences 2019, 9(12), 488; https://doi.org/10.3390/geosciences9120488 - 20 Nov 2019

Cited by 8 | Viewed by 2512

Abstract

Pounding between adjacent buildings during ground motion may result in structural damage or lead to total destruction of structures. The research on the phenomenon has recently been much advanced; however, the analyses have been carried out only for concrete, steel, and masonry structures, [...] Read more.

Pounding between adjacent buildings during ground motion may result in structural damage or lead to total destruction of structures. The research on the phenomenon has recently been much advanced; however, the analyses have been carried out only for concrete, steel, and masonry structures, while pounding between wooden buildings has not been studied so far. The aim of this paper is to show the results of detailed non-linear seismic analysis of inter-story pounding between the wood-framed buildings modelled by using the finite element method. Firstly, the modal analysis of the structures was conducted. Then, the detailed non-linear analysis of earthquake-induced collisions between two wood-framed buildings of different heights was carried out. The results of the analysis indicate that the behavior of both structures in the longitudinal as well as in the transverse direction is significantly influenced by interactions. The response of the taller building is increased in both directions. On the other hand, the response of the lower building is decreased in the longitudinal direction, while it is increased in the transverse one. The results of the study presented in the paper indicate that, due to deformability of buildings made of wood, structural interactions may change their responses much more, as compared to steel, reinforced concrete, or masonry structures. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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10 pages, 2701 KiB

Open AccessArticle

Comparison of Different Measurement Techniques as Methodology for Surveying and Monitoring Stainless Steel Chimneys

by Karol Daliga and Zygmunt Kurałowicz

Geosciences 2019, 9(10), 429; https://doi.org/10.3390/geosciences9100429 - 02 Oct 2019

Cited by 3 | Viewed by 3024

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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20 pages, 6446 KiB

Open AccessArticle

Geographical Considerations in Site Selection for Small Modular Reactors in Saskatchewan

by Raid Almalki, Joseph Piwowar and Julia Siemer

Geosciences 2019, 9(9), 402; https://doi.org/10.3390/geosciences9090402 - 18 Sep 2019

Cited by 14 | Viewed by 4488

Abstract

Saskatchewan is one of Canada’s highest emitters of greenhouse gases, largely due to the burning of lignite coal to generate electricity. The province is also the world’s second largest producer of uranium. This research was intended to establish a process for evaluating geographical [...] Read more.

Saskatchewan is one of Canada’s highest emitters of greenhouse gases, largely due to the burning of lignite coal to generate electricity. The province is also the world’s second largest producer of uranium. This research was intended to establish a process for evaluating geographical considerations in site selection for small modular reactors (SMRs) in Saskatchewan. SMRs are the next generation of electrical power, producing less than 300 megawatts (MW) and featuring a basic design that offers enhanced safety, health, and environmental benefits compared to traditional reactors. Selecting an SMR site is a two-stage process: (i) Identifying candidate site locations based solely on available geographical, economic, and logistical data—an objective process—and (ii) refining the potential locations based on public perceptions, social conventions, and political will—a subjective process. This study focused on the objective geographical considerations in SMR site selection in Saskatchewan. The study areas were subjected to a multi-criteria decision analysis based on specific criteria drawn from various Canadian federal regulation documents. Criteria weights were assigned using the analytical hierarchy process, with results for two different types of criteria weights applied for the purpose of demonstration. Three distinct cases of criteria fuzzy standardization were conducted to assign spatial suitability values for all the criteria. Spatial decision-making models were implemented in a geographic information system to identify candidate sites. Geographical maps constructed from the findings showed suitable sites for SMRs, ranging from very suitable to unsuitable based on the geographical analysis of the study area. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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11 pages, 975 KiB

Open AccessArticle

Automated Parameter Determination for Horizontal Curves for the Purposes of Road Safety Models with the Use of the Global Positioning System

by Marcin Budzynski, Kazimierz Jamroz, Jerzy Pyrchla, Wojciech Kustra, Adam Inglot and Krzysztof Pyrchla

Geosciences 2019, 9(9), 397; https://doi.org/10.3390/geosciences9090397 - 12 Sep 2019

Cited by 2 | Viewed by 2248

Abstract

This paper presents the results of research conducted to develop an automated system capable of determining parameters for horizontal curves. The system presented in this article could calculate the actual course of a road by means of a two-stage positioning of recorded points [...] Read more.

This paper presents the results of research conducted to develop an automated system capable of determining parameters for horizontal curves. The system presented in this article could calculate the actual course of a road by means of a two-stage positioning of recorded points along the road. In the first stage, measurements were taken with a Real-Time Network (RTN) receiver installed in a research vehicle. In the second stage, pictures from three cameras, also installed in the vehicle, were analyzed in order to correct the accuracy of the location of the measurement points along the road. The RTN messages and the pictures from the cameras were sent to a mobile workstation which integrated the received signals in an ArcGIS (Esri) environment. The system provides a way to quickly accumulate highly accurate data on the actual geometric parameters of a road. The computer scripts developed by the authors on the basis of the acquired data could automatically determine the parameters of the horizontal curves. The solution was tested in the field and some comments on its advantages and disadvantages are presented in this paper. The automation of data acquisition with regards to the run of a road provides effective data input for mathematical models that include the effect of horizontal curve parameters on road safety. These could be used to implement more effective ways of improving road safety. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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24 pages, 13522 KiB

Open AccessArticle

A Comparison of WorldView-2 and Landsat 8 Images for the Classification of Forests Affected by Bark Beetle Outbreaks Using a Support Vector Machine and a Neural Network: A Case Study in the Sumava Mountains

by Premysl Stych, Barbora Jerabkova, Josef Lastovicka, Martin Riedl and Daniel Paluba

Geosciences 2019, 9(9), 396; https://doi.org/10.3390/geosciences9090396 - 11 Sep 2019

Cited by 13 | Viewed by 3490

Abstract

The objective of this paper is to assess WorldView-2 (WV2) and Landsat OLI (L8) images in the detection of bark beetle outbreaks in the Sumava National Park. WV2 and L8 images were used for the classification of forests infected by bark beetle outbreaks [...] Read more.

The objective of this paper is to assess WorldView-2 (WV2) and Landsat OLI (L8) images in the detection of bark beetle outbreaks in the Sumava National Park. WV2 and L8 images were used for the classification of forests infected by bark beetle outbreaks using a Support Vector Machine (SVM) and a Neural Network (NN). After evaluating all the available results, the SVM can be considered the best method used in this study. This classifier achieved the highest overall accuracy and Kappa index for both classified images. In the cases of WV2 and L8, total overall accuracies of 86% and 71% and Kappa indices of 0.84 and 0.66 were achieved with SVM, respectively. The NN algorithm using WV2 also produced very promising results, with over 80% overall accuracy and a Kappa index of 0.79. The methods used in this study may be inspirational for testing other types of satellite data (e.g., Sentinel-2) or other classification algorithms such as the Random Forest Classifier. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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12 pages, 3397 KiB

Open AccessFeature PaperArticle

How Well can Spaceborne Digital Elevation Models Represent a Man-Made Structure: A Runway Case Study

by Kazimierz Becek, Volkan Akgül, Samed Inyurt, Çetin Mekik and Patrycja Pochwatka

Geosciences 2019, 9(9), 387; https://doi.org/10.3390/geosciences9090387 - 04 Sep 2019

Cited by 6 | Viewed by 2839

Abstract

In this case study, an active runway of a civilian airport in Zonguldak, Turkey was used to assess the suitability of spaceborne digital elevation models (DEMs) to model an anthropogenic structure. The tested DEMs include the Advanced Spaceborne Thermal Emission and Reflection Radiometer [...] Read more.

In this case study, an active runway of a civilian airport in Zonguldak, Turkey was used to assess the suitability of spaceborne digital elevation models (DEMs) to model an anthropogenic structure. The tested DEMs include the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), the Advanced Land Observing Satellite (ALOS) World 3D 30 m (AW3D30), the Shuttle Radar Topography Mission (SRTM)-1”, the SRTM-3”, the SRTM-X, the TanDEM-3”, and the WorldDEM^TM. A photogrammetric high accuracy DEM was also available for the tests. As a reference dataset, a line-leveling survey of the runway using a Leica Sprinter 150/150M instrument was performed. The selection of a runway as a testbed for this type of investigation is justified by its unique characteristics, including its flat surface, homogenous surface material, and availability for a ground survey. These characteristics are significant because DEMs over similar structures are free from environment- and target-induced error sources. For our test area, the most accurate DEM was the WorldDEM^TM followed by the SRTM-3” and TanDEM-3”, with vertical errors (LE90) equal to 1.291 m, 1.542 m, and 1.56 m, respectively. This investigation uses a method, known as the runway method, for identifying the vertical errors in DEMs. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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13 pages, 3717 KiB

Open AccessArticle

The Idea of Using Bayesian Networks in Forecasting Impact of Traffic-Induced Vibrations Transmitted through the Ground on Residential Buildings

by Agata Siemaszko, Anna Jakubczyk-Gałczyńska and Robert Jankowski

Geosciences 2019, 9(8), 339; https://doi.org/10.3390/geosciences9080339 - 01 Aug 2019

Cited by 11 | Viewed by 2978

Abstract

Traffic–induced vibrations may constitute a considerable load to buildings. In this paper, vibrations transmitted through the ground caused by wheeled vehicles are considered. This phenomenon may cause cracking of plaster, cracks in load-bearing elements or even, in extreme cases, collapse of the whole [...] Read more.

Traffic–induced vibrations may constitute a considerable load to buildings. In this paper, vibrations transmitted through the ground caused by wheeled vehicles are considered. This phenomenon may cause cracking of plaster, cracks in load-bearing elements or even, in extreme cases, collapse of the whole structure. Measurements of vibrations of real structures are costly and laborious. Therefore, the aim of the present paper is to propose a method of using Bayesian networks combined with implementation of geoscience for assessment of impact of traffic–induced vibrations on residential buildings. Firstly, the experimental tests were performed on different buildings using specialized equipment taking into account five factors: Distance from the building to the edge of the road, condition of road surface, condition of the building, the absorption of soil and the type of vehicle. Then, probabilistic analyses applying Bayesian networks were conducted and two methods of assessing the information value (EVSI method and entropy method) were compared. Finally, the developed diagnostic–decision support model was tested, so as to verify the most important parameter, affecting the possibility of structural vibrations to occur. The results of the study clearly showed that the use of Bayesian networks was a very effective approach to assess the impact of traffic-induced vibrations. The developed algorithm could be successfully applied both to existing and planned buildings, for which the source of vibration is already present or may appear in the future. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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10 pages, 1133 KiB

Open AccessArticle

The Integrated Management of Information about the Geodetic Point Fields—A Case of the Czech Republic

by Karel Janečka

Geosciences 2019, 9(7), 307; https://doi.org/10.3390/geosciences9070307 - 12 Jul 2019

Cited by 2 | Viewed by 3160

Abstract

The geodetic point fields play a crucial role in measuring a terrain, in surveying, and mapping applications. Due to the rapid development in the domain of information technologies, it makes sense to consider using the database and web technologies to manage and disseminate [...] Read more.

The geodetic point fields play a crucial role in measuring a terrain, in surveying, and mapping applications. Due to the rapid development in the domain of information technologies, it makes sense to consider using the database and web technologies to manage and disseminate the available information about the geodetic point fields. The paper presents the creation of a spatial database which integrates the information about the various kinds of established geodetic point fields (horizontal, vertical and gravitational) with the aim of enabling their effective management. Furthermore, based on the integrated spatial database, the prototype of the new information system of geodetic point fields has been developed. The functionality of the prototype also considers the requirements coming from the international efforts, i.e., the Infrastructure for Spatial Information in Europe (INSPIRE) directive. The prototype, based on Java Enterprise Edition (EE) technology, implements the features reflecting the cyber-security issues and ensures the modularity and scalability of the system, which is important for further development of the system and dissemination and accessibility of the information about the geodetic point fields via modern web technologies. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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15 pages, 2777 KiB

Open AccessArticle

Geo-Analysis of Compatibility Determinants for Data in the Land and Property Register (LPR)

by Katarzyna Kocur-Bera and Marta Stachelek

Geosciences 2019, 9(7), 303; https://doi.org/10.3390/geosciences9070303 - 10 Jul 2019

Cited by 10 | Viewed by 3220

Abstract

The development of modern technologies and accessibility of data on space and the natural environment has led to their increasing use for socio-economic purposes. Data users believe that these systems reflect the reality in the field. This applies in particular to databases used [...] Read more.

The development of modern technologies and accessibility of data on space and the natural environment has led to their increasing use for socio-economic purposes. Data users believe that these systems reflect the reality in the field. This applies in particular to databases used for construction investment projects or as the basis for calculations of financial obligations, e.g., taxes. The Land and Property Register (LPR), which is part of the Land Administration System, serves a number of economic and legal purposes. This geo-system often contains low-quality information regarding the technical potential of modern data acquisition methods and is continuously updated. The authors propose a two-step analysis of data contained in the LPR. The first step identified the sources of discrepancies between data from the LPR and the reality in the field. The second step emphasises the importance of the factors under analysis, which include both a plot’s geometric parameters, the geo-location features (associated with the natural environment elements) and factors associated with the supplementary data acquisition methods. The results show that sufficient quality data play the main role in achieving compatibility between the data in the Land and Property Register and with reality. Studies conducted so far have dealt with data on a global scale and were based on in situ data and focused on the specific values of each plot under analysis. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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16 pages, 6831 KiB

Open AccessEditor’s ChoiceArticle

Combined Close Range Photogrammetry and Terrestrial Laser Scanning for Ship Hull Modelling

by Pawel Burdziakowski and Pawel Tysiac

Geosciences 2019, 9(5), 242; https://doi.org/10.3390/geosciences9050242 - 26 May 2019

Cited by 29 | Viewed by 5475

Abstract

The paper addresses the fields of combined close-range photogrammetry and terrestrial laser scanning in the light of ship modelling. The authors pointed out precision and measurement accuracy due to their possible complex application for ship hulls inventories. Due to prescribed vitality of every [...] Read more.

The paper addresses the fields of combined close-range photogrammetry and terrestrial laser scanning in the light of ship modelling. The authors pointed out precision and measurement accuracy due to their possible complex application for ship hulls inventories. Due to prescribed vitality of every ship structure, it is crucial to prepare documentation to support the vessel processes. The presented methods are directed, combined photogrammetric techniques in ship hull inventory due to submarines. The class of photogrammetry techniques based on high quality photos are supposed to be relevant techniques of the inventories’ purpose. An innovative approach combines these methods with Terrestrial Laser Scanning. The process stages of data acquisition, post-processing, and result analysis are presented and discussed due to market requirements. Advantages and disadvantages of the applied methods are presented. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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23 pages, 5696 KiB

Open AccessArticle

The Noise Properties and Velocities from a Time-Series of Estonian Permanent GNSS Stations

by Tarmo Kall, Tõnis Oja, Karin Kollo and Aive Liibusk

Geosciences 2019, 9(5), 233; https://doi.org/10.3390/geosciences9050233 - 21 May 2019

Cited by 7 | Viewed by 3658

Abstract

The aim of this study was to estimate the noise properties, velocities, and their uncertainties from a time-series of selected (~9 years long) Estonian continuously operating Global Navigation Satellite System (GNSS) stations. Two software packages based on different processing methods, Gipsy–Oasis and Bernese, [...] Read more.

The aim of this study was to estimate the noise properties, velocities, and their uncertainties from a time-series of selected (~9 years long) Estonian continuously operating Global Navigation Satellite System (GNSS) stations. Two software packages based on different processing methods, Gipsy–Oasis and Bernese, were used for daily coordinate calculations. Different methods and software (Tsview, Hector, and MIDAS) were used for coordinate time-series analysis. Outliers were removed using three different strategies. Six different stochastic noise models were used for trend estimation altogether with the analysis of the noise properties of the residual time-series with Hector. Obtained velocities were compared with different land uplift and glacial isostatic adjustment models (e.g., ICE-6G (VM5a), NKG2016LU, etc.). All compared solutions showed similar fit to the compared models. It was confirmed that the best fit to the time-series residuals were with the flicker noise plus white noise model (for the North and East component) and generalized Gauss–Markov model (for Up). Velocities from MIDAS, Tsview, and Hector solutions within the same time-series (Gipsy–Oasis or Bernese) agreed well but velocity uncertainties differed up to four times. The smallest uncertainties were obtained from Tsview; the MIDAS solution produced the most conservative values. Although the East and Up component velocities between Gipsy and Bernese solutions agreed well, the North component velocities were systematically shifted. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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Graphical abstract

14 pages, 2394 KiB

Open AccessArticle

Estimating Residential Property Values on the Basis of Clustering and Geostatistics

by Beata Calka

Geosciences 2019, 9(3), 143; https://doi.org/10.3390/geosciences9030143 - 24 Mar 2019

Cited by 19 | Viewed by 3968

Abstract

The article presents a two-stage model for estimating the value of residential property. The research is based on the application of a sequence of known methods in the process of developing property value maps. The market is divided into local submarkets using data [...] Read more.

The article presents a two-stage model for estimating the value of residential property. The research is based on the application of a sequence of known methods in the process of developing property value maps. The market is divided into local submarkets using data mining, and, in particular, data clustering. This process takes into account only a property’s non-spatial (structural) attributes. This is the first stage of the model, which isolates local property markets where properties have similar structural attributes. To estimate the impact of the spatial factor (location) on property value, the second stage involves performing an interpolation for each cluster separately using ordinary kriging. In this stage, the model is based on Tobler’s first law of geography. The model results in property value maps, drawn up separately for each of the clusters. Experimental research carried out using the example of Siedlce, a city in eastern Poland, proves that the estimation error for a property’s value using the proposed method, evaluated using the mean absolute percentage error, does not exceed 10%. The model that has been developed is universal and can be used to estimate the value of land, property, and buildings. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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20 pages, 5787 KiB

Open AccessArticle

Geoscience Methods in Real Estate Market Analyses Subjectivity Decrease

by Malgorzata Renigier-Bilozor, Artur Janowski and Marek Walacik

Geosciences 2019, 9(3), 130; https://doi.org/10.3390/geosciences9030130 - 16 Mar 2019

Cited by 27 | Viewed by 4807

Abstract

Real estate management, including real estate market analysis, is part of a so-called geosystem. In recent years, the popularity of creating various types of systems and automatic solutions in real estate management, including those related to property classification and valuation, has been growing [...] Read more.

Real estate management, including real estate market analysis, is part of a so-called geosystem. In recent years, the popularity of creating various types of systems and automatic solutions in real estate management, including those related to property classification and valuation, has been growing in the world, mainly to reduce the impact of human subjectivity, to increase the scope of analyses and reduce research time. A very important fact that should be underlined is that properties are strongly related to geolocation (space) and strongly determine it. Authors proposed in the paper solutions that highlight implementation of geoscience and “geo-approach” combined with fuzzy logic methods that allow to decrease subjectivity in property analyses and diminish uncertainty in decision making process. The proposed methodology involves three main problematic components of decision support system in property investment analyses development with the use of geo-technologies such as: determination of the database model; elaboration geo-property-zones with geoprocessing activities; identification of homogeneous group of properties transactions. The influence of spatial decision factor determined in the study lead to objective and precise calculation of value differentiation from 22 to 43% depending on the property’s remoteness to the sea. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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11 pages, 5409 KiB

Open AccessArticle

The Optimal Location of Ground-Based GNSS Augmentation Transceivers

by Jacek Rapinski and Artur Janowski

Geosciences 2019, 9(3), 107; https://doi.org/10.3390/geosciences9030107 - 27 Feb 2019

Cited by 3 | Viewed by 2857

Abstract

Modern Global Navigation Satellite Systems (GNSS) allow for positioning with accuracies ranging from tens of meters to single millimeters depending on user requirements and available equipment. A major disadvantage of these systems is their unavailability or limited availability when the sky is obstructed. [...] Read more.

Modern Global Navigation Satellite Systems (GNSS) allow for positioning with accuracies ranging from tens of meters to single millimeters depending on user requirements and available equipment. A major disadvantage of these systems is their unavailability or limited availability when the sky is obstructed. One solution is to use additional range measurements from ground-based nodes located in the vicinity of the receiver. The highest accuracy of distance measurement can be achieved using ultra wide band (UWB) or ZigBee phase shift measurement. The position of the additional transmitter must be carefully selected in order to obtain the optimal improvement in the dilution of precision (DOP), which reflects the improvement in the geometry of solution. The presented case study depicts a method for selecting the optimal location of a ground-based ranging source. It is based on a search of a minimum DOP value as a transmitter location function. The parameters of objective function are the elevation and azimuth of the transceiver. The solution was based on a limited-memory Broyden–Fletcher–Goldfarb–Shanno with Box constraints (L-BFGS-B) method and a numerical optimization algorithm for parameter value estimation. The presented approach allows for the selection of the optimal location of a ground-based source of ranging signals in GNSS processing from a geometry of solution point of view. This can be useful at the design stage of an augmentation network of ground-based transceivers. This article presents a theoretical basis and a case study presenting the selection of the optimal location of a ground-based ranging source. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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14 pages, 5319 KiB

Open AccessEditor’s ChoiceArticle

Down-Sampling of Point Clouds for the Technical Diagnostics of Buildings and Structures

by Czesław Suchocki and Wioleta Błaszczak-Bąk

Geosciences 2019, 9(2), 70; https://doi.org/10.3390/geosciences9020070 - 30 Jan 2019

Cited by 32 | Viewed by 4258

Abstract

Terrestrial laser scanning (TLS) is a non-destructive testing method for the technical assessment of existing structures. TLS has been successfully harnessed for monitoring technical surface conditions and morphological characteristics of historical buildings (e.g., the detection of cracks and cavities). TLS measurements with very [...] Read more.

Terrestrial laser scanning (TLS) is a non-destructive testing method for the technical assessment of existing structures. TLS has been successfully harnessed for monitoring technical surface conditions and morphological characteristics of historical buildings (e.g., the detection of cracks and cavities). TLS measurements with very high resolution should be taken to detect minor defects on the walls of buildings. High-resolution measurements are mostly needed in certain areas of interest, e.g., cracks and cavities. Therefore, reducing redundant information on flat areas without cracks and cavities is very important. In this case, automatic down-sampling of datasets according to the aforementioned criterion is required. This paper presents the use of the Optimum Dataset (OptD) method to optimize TLS dataset. A Leica ScanStation C10 time-of-flight scanner and a Z+F IMAGER 5016 phase-shift scanner were used during the research. The research was conducted on a specially prepared concrete sample and real object, i.e., a brick citadel located on the Kościuszko Mound in Cracow. The reduction of dataset by the OptD method and random method from TLS measurements were compared and discussed. The results prove that the large datasets from TLS diagnostic measurements of buildings and structures can be successfully optimized using the OptD method. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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23 pages, 2974 KiB

Open AccessArticle

A Comparative Study of the AHP and TOPSIS Techniques for Dam Site Selection Using GIS: A Case Study of Sistan and Baluchestan Province, Iran

by Ali Jozaghi, Babak Alizadeh, Mohsen Hatami, Ian Flood, Mohammad Khorrami, Nastaran Khodaei and Erfan Ghasemi Tousi

Geosciences 2018, 8(12), 494; https://doi.org/10.3390/geosciences8120494 - 17 Dec 2018

Cited by 116 | Viewed by 15890

Abstract

The application of multiple criteria decision-making (MCDM) techniques in real-life problems has increased in recent years. The need to build advanced decision models with higher capabilities that can support decision-making in a broad spectrum of applications, promotes the integration of MCDM techniques with [...] Read more.

The application of multiple criteria decision-making (MCDM) techniques in real-life problems has increased in recent years. The need to build advanced decision models with higher capabilities that can support decision-making in a broad spectrum of applications, promotes the integration of MCDM techniques with applicable systems, including artificial intelligence, and Geographic Information Systems (GIS). The Analytic Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are among the most widely adopted MCDM techniques capable of resolving water resources challenges. A critical problem associated with water resource management is dam site selection. This paper presents a comparative analysis of TOPSIS and AHP in the context of decision-making using GIS for dam site selection. The comparison was made based on geographic and water quality criteria. The geographical criteria are geology, land use, sediment, erosion, slope, groundwater, and discharge. The water quality criteria include Soluble Sodium Percentage, Total Dissolved Solid, Potential of Hydrogen, and Electrical Conductivity of water. A ratio estimation procedure was used to determine the weights of these criteria. Both methods were applied for selection of optimal sites for dams in the Sistan and Baluchestan province, Iran. The results show that the TOPSIS method is better suited to the problem of dam site selection for this study area. Actual locations of dams constructed in the area were used to verify the results of both methods. Full article

(This article belongs to the Special Issue Geodesy and Geomatics Engineering)

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