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Öğe A RESEARCH ON EFFECTS OF DIFFERENT SCANNING RESOLUTIONS DEPENDING ON THE NUMBER OF TARGET USED IN TERRESTRIAL LASER SCANNING(STEF92 TECHNOLOGY LTD, 2016) Gumus, KutalmisTerrestrial Laser Scanners (TLS) are utilized in many application areas thanks to advances in technology. Accuracy and reliability of the outcome obtained through the scanners mostly depend on the resolution and accuracy of the obtained data. Location information as to smallest detail on object can be acquired thanks to point clouds obtained by virtue of terrestrial laser scanners. The point density reflecting the surface of the most appropriate object should be selected according to aim of the work carried out, the desired accuracy, time, cost, present hardware and software as well as the desired outcome. 3 or more than 3 targets have to be employed for transformation of the coordinates obtained from the laser scanner into desired coordinate system. The targets utilized have to be placed appropriately within the scanning area. It has been tried to determine the effects of targets which are used in georeferencing and which are placed in different numbers and directions and the scan resolutions thereof on point location accuracy in this study. For this purpose, a study has been carried out at the Calibration Laboratory of Faculty of Civil Engineering of Yildiz Technical University. Optech ILRIS 3D laser scanner and Leica TPS 1201 total station were employed in the cited application. 12 targets with appropriate geometry were placed in the test area to be scanned. Georeferencing performed by the use of targets with directions and numbers varying according to different scan resolutions and their point positions has been tried to be re- determined. Comparisons were made according to the locations of these 12 target points determined by the Total Station. It has been tried to determine if there was a difference between the point positions obtained by considering the changing number of targets as well as the scan resolution. It has been determined that point position accuracy has decreased depending on the increase of the scan resolution. Choice and number of appropriate targets in addition to direction and orientation of target with respect to each other affect point position accuracy.Öğe A research on the effect of different measuring configurations in Network RTK applications(ELSEVIER SCI LTD, 2016) Gumus, KutalmisThe aim of this article is to try to determine whether there's a statistically significant difference between coordinates obtained under different elevation angles and measuring epochs through different correction methods in Network Real Time Kinematic Applications. For this purpose, analysis of variance was used. When the statistical data obtained according to different variables are compared, the accuracy seems to be less in the direction of h coordinate axis. There is no a statistically significant difference among the values obtained according to different epoch numbers in all directions of the coordinate axes. The subsets formed according to satellite elevation angles show similar characteristics along Y and h coordinate axes while they differ 30 degrees according to other angles in the direction of X coordinate axis. Based on the correction methods, while FKP and VRS method show different characteristics with respect to each other, MAC method shows similar characteristics compared to other methods. (C) 2015 Elsevier Ltd. All rights reserved.Öğe A statistical investigation on the effects of different GNSS systems(2023) Gumus, Kutalmis; Çelik, Cahit; Gümüş, MünevverThis study is to investigate the effects of various solutions of GPS only, GLONASS only, and combined GPS/GLONASS observations under different elevation angles on different GNSS days by using Magic GNSS software. Different elevation angles and measurement days were considered to investigate the increasing or decreasing number of satellites’ effects on the measurement accuracy, and positioning accuracy affected by the solutions of GPS only, GLONASS only, and combined GPS/GLONASS observations, respectively. The assessment was based on statistical tests, namely ANOVA and Post Hoc tests. A test network, consisting of all the continuous stations of the ISKI CORS network in Istanbul city, was used to fulfill the aims of the study. The results showed that significant differences between positions of points obtained by GNSS in various elevation angles and with different satellite configurations were determined. Different satellite and measurement configurations affect position accuracy. In addition, the results showed that on the 136th GNSS day, significant differences in X and Z components were found while in Y components there were no significant differences encountered. In conclusion, combined GPS/GLONASS solutions produced better results under small elevation angles of 5° 10° or 15° than the solutions of GPS-only and GLONASS-only observations.Öğe Accuracy investigation of height obtained from Classical and Network RTK with ANOVA test(ELSEVIER SCI LTD, 2016) Gumus, Kutalmis; Selbesoglu, Mahmut Oguz; Celik, Cahit TagiTo assess the accuracy of vertical components obtained by Classical RTK and Network Real Time Kinematic positioning with different correction methods with setting of different number of epoch, height differences obtained from precise geometric leveling was used as reference height differences along with those obtained from static GPS only solutions, and combined solutions of GPS and GLONASS on different GNSS days. One-way variance analysis (ANOVA) were applied to the height differences to test them whether they are significantly different or not. The significant differences, if any, were further tested by using Post Hoc test to reveal the effects of the method used, the epoch number, or the measuring time, which is responsible for the significant differences. The results from ANOVA showed that the number of epoch had not much effect on the vertical components but on the correction methods. MAC method presented the most deviated results compared to the other methods with different GNSS days' solutions. In general, VRS method was found to be the most consistent method among others used. This study is important in both; an accuracy assessment with respect to the most precise method in heights (i. e., precise geometric leveling) was carried. The techniques (ANOVA and Post Hock Test) used in the accuracy assessment. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Analyzing land use and climate change impacts of Suğla water storage in Turkey(Springer Wien, 2024) Ciftci, Hasan Cagatay; Gumus, Kutalmis; Gumus, Munevver GizemLarge water masses affect the land use of their surroundings and change the regional climate. Many methods are used to determine changes in regional climate and land use. This study aims to investigate the impact of the Su & gbreve;la water storage site in Turkey on land use and climate before and after 2006, the year the site became operational. The effects of the Su & gbreve;la water storage site on the climate and land use of the region were investigated using trend analyses, Autoregressive Integrated Moving Averages (ARIMA) models, and remote sensing techniques. For these purposes, increasing or decreasing trends in the meteorological time series covering the years 1960-2020 obtained from four meteorological stations in this region were determined by trend analysis. ARIMA models, a time series estimation and forecasting method, were used to make predictions for the next 10-year period (2020-2030) for meteorological data. With remote sensing techniques, changes in land use were determined using Landsat satellite images from 1984, 1990, 2000, 2006, 2010, 2020 and 2022. As a result of the study, increasing and decreasing trends were detected in trend analysis and ARIMA forecasts at all stations. It was observed that the water bodies have increased by 1% since 2006, when the site started to hold water, and there has been a significant increase from forest and semi-natural areas to agricultural areas. These results show that the land use around the Su & gbreve;la water storage area has changed significantly, with agricultural areas expanding.Öğe Comparison of Different Parameters of Feedforward Backpropagation Neural Networks in DEM Height Estimation for Different Terrain Types and Point Distributions(Mdpi, 2023) Sen, Alper; Gumus, KutalmisDigital Elevation Models (DEMs) are commonly used for environment, engineering, and architecture-related studies. One of the most important factors for the accuracy of DEM generation is the process of spatial interpolation, which is used for estimating the height values of the grid cells. The use of machine learning methods, such as artificial neural networks for spatial interpolation, contributes to spatial interpolation with more accuracy. In this study, the performances of FBNN interpolation based on different parameters such as the number of hidden layers and neurons, epoch number, processing time, and training functions (gradient optimization algorithms) were compared, and the differences were evaluated statistically using an analysis of variance (ANOVA) test. This research offers significant insights into the optimization of neural network gradients, with a particular focus on spatial interpolation. The accuracy of the Levenberg-Marquardt training function was the best, whereas the most significantly different training functions, gradient descent backpropagation and gradient descent with momentum and adaptive learning rule backpropagation, were the worst. Thus, this study contributes to the investigation of parameter selection of ANN for spatial interpolation in DEM height estimation for different terrain types and point distributions.Öğe DESIGN OF DOUBLE-EGG CURVE IN THE LINK ROADS OF TRANSPORTATION NETWORKS(UNIV OSIJEK, TECH FAC, 2015) Koc, Ibrahim; Gumus, Kutalmis; Selbesoglu, Mahmut OguzThe turns from highways to settlement areas are achieved by link roads. For the safety of these turns, turning radii are required to be large. However, it is not always possible to achieve these turnings by means of arcs of circle with large radius, as different factors, such as topography, the state of settlement, problems impossible to overcome and economic conditions, do not allow designing such a route. Instead, for the sake of traffic, linear variation of the line curvature or maintaining the line curvature at constant value is highly desirable. One of the line geometries is the clothoid egg curve. Single and double type clothoid egg curves are used in many applications. In this study, the calculation and design of double-egg curve are explained by equations and figures in detail. For the design of two egg curves used in rotation from main road to connecting road in transportation networks as application, an example is provided for a better understanding of the subject. The main points of rotation geometry with the coordinates of auxiliary points and other intermediate results are given in a table. The main purpose of this study, the theory and calculations of two egg curves will provide basis to practitioners on a sample in a detailed way. By the fulfilment of design and its calculation of this rotation geometry which provides safer and more comfortable driving, it is hoped to be useful for practitioners.Öğe FINDING AN APPROPRIATE METHOD FOR SMALL-SCALE SURVEYING APPLICATION AMONG REAL TIME SATELLITE-BASED METHODS IN TURKEY(UNIV OSIJEK, TECH FAC, 2013) Gumus, Kutalmis; Celik, Cahit Tagi; Koc, IbrahimIn this paper, for small-scale surveying applications, investigation of appropriate methods among classical RTK, net-RTK which provides Virtual Reference Station (VRS), and Fl chen-Korrektur Parameter (FKP) corrections were performed. A test network consisting of 56 stations has been established in Istanbul. Measurements were carried out using the above methods. Five separate tests were applied on the coordinates obtained by the methods. The results showed that the methods from the most accurate to the least accurate one were classical RTK, Net-RTK-VRS and Net-RTK-FKP. In general, horizontal components were found to be two times better than vertical components ranging from 1 mm to approximately 5 cm.Öğe GIS INVESTIGATION OF SITE SELECTION OF HISTORICAL STRUCTURES: THE CASE OF KNIDOS (DATCA, TURKEY)(Univ Agean, Dept Mediterranean Stud, 2017) Gumus, M. Gizem; Durduran, S. Savas; Bozdag, Asli; Gumus, KutalmisIn archaeological research, the collection, storage, query and analysis of data is conducted with the help of the Geographical Information System (GIS) in order to acquire the most accurate information about the area. Spatial analyses made with the help of GIS in ancient cities contribute to revealing the social, cultural and survival features of these cities. The aim of this study is to examine the rationale for spatial site selection in Knidos ancient city, which is in the Turkish province of Mugla and which has different city planning with its geographical features. For this reason, firstly, a digital elevation model that reveals the topography of the city was constituted. Then, the database design and spatial analyses (slope, aspect and visibility) were conducted in line with the aim of the study in ArcGIS 10.2 Software. The site selection rationale for structures was evaluated through spatial analyses (slope, aspect and visibility) in Knidos ancient city. Site selection rationales of the historical structures have been ascertained related to the preferred planning form of the period (grille planning), the geography of the city, the functions given to the historical structures, the visibility of structures, the ports which were as a focal point of the city, the ideological point of view and the reflection power of the ruler's.Öğe INVESTIGATION OF ACCURATE METHOD IN 3-D POSITION USING CORS-NET IN ISTANBUL(UNIV FEDERAL PARANA, CENTRO POLITECNICO, 2012) Gumus, Kutalmis; Celik, Cahit Tagi; Erkaya, HalilIn this study, for Istanbul, there are two Cors Networks (Cors-TR, Iski Cors) providing Virtual Reference Station (VRS), and Flachen Korrektur Parameter (FKP), corrections to rover receiver for determining 3-D positions in real time by Global Positioning System (GPS). To determine which method (or technique) provides accurate method for position fixing, a test network consisting of 49 stations was set up in Yildiz Technical University Davudpasa Campus. The coordinates of the stations in the test network were determined by conventional geodetic, classical RTK, VRS and FKP methods serviced by both Cors-TR and Iski Cors. The results were compared to the coordinates by the conventional method by using total station. The results showed a complex structure as the accuracy differs from one component to another such as in horizontal coordinates, Y components by CorsTR_VRS and Cors_TR_FKP showed 'best' results while the same technique provided X components consistent accuracy with the Y component but less accurate than by real time kinematic (RTK). In vertical components, of all the techniques used for the h components, CorsTR_VRS showed 'best' accuracy with three outliers.Öğe REAL TIME DIGITAL AND META DATA COLLECTION IN FORMING URBAN INFORMATION SYSTEM: CASE STUDY ELAZIG (TURKEY)(STEF92 TECHNOLOGY LTD, 2016) Kisaaga, M. Gizem; Durduran, S. Savas; Gumus, KutalmisIn general, the cost of field study and time spend are high in the process of collecting data for urban information system. The precision and accuracy of the data varies depending on the complexity of the conditions. Furthermore, data standardization is also a problem. To bring the data into the same standard demands extra cost. Therefore, various problems become apparent concerning extra time spend, cost and workforce by the process of the data collected from the field. In this study, advantageous and disadvantageous of use of a tablet computer in real time data collection compared to conventional printed documents, problems faced during the field study and possible recommendations for these problems were to be discussed. This study concerned the urban information system case of Elazig, Turkey where an application by Mapcodex Mapland installed in a tablet with windows operating system was used for real time GIS-based data collection, and the results were presented. This study also aimed at compensation of the gaps experienced in the process of data collections in existing current city information system and giving more flexible recommendations to the problems faced.Öğe Studying the Repeatability of Measurements Obtained via Network Real-Time Kinematic Positioning at Different Times of the Day(Univ Nac Colombia, Fac Ingenieria, 2024) Gumus, KutalmisThe network real-time kinematic (NRTK) positioning technique is currently used in numerous applications. The aim of this study was to better understand the process of obtaining accurate positions by statistically evaluating the significance of differences between repeated measurements for a single point at different times of the day (morning, noon, and evening) using the Virtual Reference Station (VRS), Fl & auml;chen Korrektur Parameter (FKP), and Master Auxiliary Concept (MAC) correction methods. An analysis of variance (ANOVA) was used to this effect. Further analysis was carried out to determine the accuracy and precision of the coordinate differences obtained via a static GNSS (global navigation satellite system) and by averaging the repeated measurements. It was determined that the accuracy and precision of the vertical component of the coordinates were lower than that of the horizontal component. The FKP correction method yielded the best results. It was observed that the accuracy and precision of the measurements taken at noon were the lowest. The ANOVA showed that the differences between repeated measurements were statistically significant and that there were outlier measurements. The results of this study are important for NRTK users to be able to statistically evaluate different measurement configurations and obtain positions with the desired accuracy and precision.Öğe TESTING REAL TIME KINEMATIC GNSS (GPS AND GPS/GLONASS) METHODS IN OBSTRUCTED AND UNOBSTRUCTED SITES(ASSOC SURVEYORS SLOVENIA, 2013) Pirti, Atinc; Yucel, Mehmet Ali; Gumus, KutalmisThis paper describes an experiment carried out with the GNSS RTK method to combine GPS and GLONASS measurements in obstructed and unobstructed sites. This study investigates the RTK achievable accuracy and repeatability under different satellite constellations and site conditions in Samatya (coastal area), Istanbul, Turkey. The RTK (GPS and GPS/GLONASS) measurement techniques are described and compared in terms of productivity and precision. Surveyed area, control and test points as well as the impact area of trees where the precision decreases are visualised using Autodesk LandXplorer Studio ProfessionalTM Software. These obtained results indicate that integrating RTK GPS system with GLONASS is favoured for surveying applications.
