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Öğe Computing of volume of excavation areas by digital close range photogrammetry(Springer Nature, 2008) Yılmaz, Hacı Murat; Yakar, MuratPerformance of volume calculation by digital close range photogrammetry has been investigated. The potential use of 3D photomodelling in volume calculation of complex objects which may not be accessible and are sometimes in a risky location was studied using an excavation area and a natural hill as examples. The volumes obtained from 3D photomodels of objects were compared with the volumes calculated using geodetic techniques. The results were analyzed with respect to time, cost, and accuracy. It was found that the photogrammetric method has advantages of 21.89% in time, 12.11% in accuracy, and 33.33% in cost as compared to the classical method.Öğe Monitoring of corrosion in fairy chimney by close range photogrammetry(ISPRS Archives, 2008) Yılmaz, Haci Murat; Yakar, Murat; Yıldız, FerruhA Fairy Chimney is a conical rock formation and typically found in the Cappadocia region of Turkey. It consists of a cap of hard rock resting on a cone-shaped pinnacle of softer rock. The geology of areas where Fairy Chimneys form typically comprises a thick layer of tuff (consolidated volcanic ash), covered by a thin layer of basalt or other volcanic rocks that are more resistant to erosion than the underlying tuff. Over time, cracks in the basalt allow the much softer tuff to be eroded and washed away. Fairy Chimneys are formed where a small cap or boulder of the original basalt remains, and protects a cone of tuff beneath it from erosion. Eventually, the tuff will be undercut to the extent that the cap falls off, and the remaining cone is then quickly eroded In this study, corrosion on the surface of fairy chimney, which is located in Selime district of Aksaray in Turkey, has been examined by digital close range photogrammetry. The fairy chimney has been evaluated by photogrammetric in two period. Its three dimensional (3D) model has been obtained. Its volume has been calculated from known heights. Corrosion in Fairy Chimney has been investigated.Öğe The effect of interpolation methods in surface definition: An experimental study(Wiley-Blackwell, 2007) Yılmaz, Hacı MuratMappings of the earth surface and their representation in 3D (three?dimensional) models are commonly used in most recent research. Modeling research, which starts with classical surveying methods, acquires new dimensions matching the modern technologies. 3D models of any object or earth surface can be used in much visual and scientific research. A digital model of the landscape is an important part within creation of geo?information systems used in the public administration and in the commercial sphere. It is an important tool in applications such as geomorphology, hydrology, geology, cartography, ecology, mining etc. Values of volume in terrains that do not have regular geometric structure can be obtained more accurately by using 3D models of surfaces with respect to developing technology. Basic data of 3D models must indicate 3D coordinates of the surveyed object in the reference frame. Distribution and intensity of points are important factors in modeling earth surfaces. A minimum number of points is desired in defining an object in 3D. Interpolation methods employing different mathematical models are used to obtain 3D models of terrain surfaces. In this study, the effect of interpolation methods in defining a terrain surface is investigated. For this purpose, a uniform surface, hill?shaped artificial object with a known volume is employed. The 3D surface and volume are calculated by using 12 different interpolation methods. Point distribution, point intensity and accuracy of point measurements are not considered. The same data set was used for all the interpolation methods. The interpolation methods are compared and evaluated based on the results.Öğe Using landsat data to determine land use/land cover changes in Samsun, Turkey(Springer Nature, 2007) Güler, Mustafa; Yomralıo?u, Tahsin; Reis, SelçukThe rapid industrialization and urbanization of an area require quick preparation of actual land use/land cover (LU/LC) maps in order to detect and avoid overuse and damage of the landscape beyond sustainable development limits. Remote sensing technology fits well for long-term monitoring and assessment of such effects. The aim of this study was to analyze LU/LC changes between 1980 and 1999 in Samsun, Turkey, using satellite images. Three Landsat images from 1980, 1987 and 1999 were used to determine changes. A post classification technique was used based on a hybrid classification approach (unsupervised and supervised). Images were classified into six LU/LC types; urban, agriculture, dense forest, open forest-hazelnut, barren land and water area. It is found that significant changes in land cover occurred over the study period. The results showed an increase in urban, open forest/hazelnut, barren land and water area and a decrease in agriculture and dense forest in between 1980 and 1999. In this period, urban land increased from 0.77% to 2.47% of the total area, primarily due to conversions from agricultural land and forest to a lesser degree. While the area of dense forest decreased from 41.09% to 29.64% of the total area, the area of open forest and hazelnut increased from 6.73% to 11.88%.Öğe Geology and geomorphology of Gumushane area, northeastern Turkey using digitally enhanced satellite images and geographical information system(Geological Society of India, 2007) Reis, Selçuk; Yalçın, Ali; Nişancı, Recep; Yomralıoğlu, TahsinGeomorphic data is required in multi-disciplinary studies for engineering projects, hazard zone delineation, risk assessment and planning. In the present study, Landsat ETM+ data was used to delineate the geological and geomorphological features in the (semi) and Gumushane region of Turkey. This region has a complex geology and is located north of the North Anatolian Fault (NAF) in northeastern Turkey. The geological, topographical and structural characteristics of the area were studied using digital image processing techniques such as band rationing, principal component analysis (PCA) and generation of false colour composite (FCC) of ETM data. Georeferenced information such as land cover data, hydrology and digital elevation models (DEMs) were integrated with remotely sensed data to enable better interpretation, analysis and mapping of geomorphic features. The interpretation of the new data contributes to a more detailed geological mapping of selected test sites that were studied during the fieldwork. Finally, the understanding of the geologic/geomorphologic process in the complex and rugged topography of the Gumushane region was much improved by employing image enhancement and GIS techniques.Öğe Modelling the relationship between water level and vertical displacements on the Yamula Dam, Turkey(Natural Hazards and Earth System Sciences, 2007) Bayrak, Temelonitoring deformation pattern of dams is often one of the most effective ways to understand their safety status. The main objective of the study is to find the extent to which rising reservoir level affects the mechanism of deformation of The Yamula Dam under certain change in the reservoir level conditions during to the first filling period. Three different deformation analysis techniques, namely static, kinematic and dynamic, were used to analyze four geodetic monitoring records consisting of vertical displacements of nine object points established on the Dam and six reference points surrounding of it, to see whether the rising reservoir level have a role in the vertical deformations during the first filling period. The largest vertical displacements were in the middle of the dam. There is an apparent linear relationship between the dam subsidence and the reservoir level. A dynamic deformation model was developed to model this situation. The model infers a causative relationship between the reservoir level and the dam deformations. The analysis of the results determines the degree of the correlation between the change in the reservoir level and the observed structural deformation of the dam.Öğe Detection of current and potential hazelnut plantation areas in Trabzon, North East Turkey using GIS and RS(Triveni Enterprises, 2006) Reis, Selçuk; Yomralıoğlu, TahsinMonitoring agricultural products requires the periodic determination of land cover and the production of land use policies in an optimum way. The hazelnut is one of the important Turkish agricultural exports and Turkey provides 77% of the world's hazelnuts. In Turkey, hazelnut production exceeds the demand; new regulations have been enacted to create new land use policies. By putting into practice regulations restricting hazelnut plantation areas, a more efficient and productive hazelnut harvest policy could be created. Therefore, more information on existing land cover is required to determine optimum (or ideal) potential hazelnut areas (PHA) and to forecast future crop production. The principle aim of this study is to create a methodology for determining existing PHA, using Geographic information system (GIS) and remote sensing (RS) techniques regarding to support hazelnut policy developers and economists. This study was basically carried out in the province of Trabzon, which is one of the most important hazelnut production areas in Turkey. Landsat ETM+ image was used to generate a current land cover classification. Using the supervised classification method, overall accuracy was determined to be 84.7%. Suitable hazelnut areas were determined according to criteria settled by government regulations.Öğe Investıgatıon of spatıal accuracy of hıgh-resolutıon (50cm) worldvıew-2(Selçuk Üniversitesi, 2016) Mutluoğlu, Ömer; Yakar, Murat; Yılmaz, Hacı MuratNowadays, Very High Resolution Satellite (VHRS) images have been used for many applications intensively. Using of the digital satellite images in relevant approaches may give more accurate ideas about the researched fields. Besides, different methods could be used for geospatial informations from relevant digital data in many disciplines. The most importance reason of using the maps, which are derived from VHRS images, is accuracy of data. To obtain maps from VHRS images or use VHRS images as map, the VHRS images require rectification. For an accurate rectification process, Ground Control Points (GCPs) must be marked in the field. In this study, spatial accuracy of the stereo WorldView-2 satellite image (0.5 m resolution) was investigated at a test area. For this, 31 GCP points were established. These points were used as controls and check point. Block adjustment was made using a different number of control and check points. The impact of the number of control points upon the adjustment results was also investigated. As a result of adjustment using a 5-point control and 26 check points; root mean square error in the 53 cm x direction, 17 cm y direction, 63 cm in z-direction for control points have been obtained. For check points, 55 cm x direction, 26 cm y direction and z direction 65 cm root mean square error were found. Also coordinates obtained from the stereo model and the field determined by the geodetic methods coordinates of points were compared. The average position error of a point is 48 cm according to comparison results.Öğe Yamula barajındaki düşey deformasyonların jeodezik yöntemlerle izlenmesi(Harite ve Kadastro Mühendisleri Odası, 2006) Bayrak, TemelKayseri iline 35 km uzaklıkta Kızılırmak nehri üzerinde inşa edilmiş olan Yamula barajının zamansal davranışı yapımından itibaren 1,5 yıl sürecinde gerçekleştirilmiş dört periyotjeodezik ölçü ile izlenmiştir. Su seviyesinin yükselmesine bağlı olarak barajın düşey yönde gerçekleşen deformasyonlarının belirlenmesi amacıyla, çalışmada, biri statik ve diğeri kinematik olmak üzere iki farklı deformasyon analizi yöntemi kullanılmıştır. Sonuçlar baraj üzerindeki tüm noktaların hareket halinde olduğunu göstermiştir. Kinematik yöntem sonuçları, özellikle baraj ortasındaki noktaların su seviyesinin yükselmesine bağlı olarak anlamlı bir ivmeli hareket sergilediklerini ortaya koymuştur. Çizilen grafikler, su seviyesinin yükselmesi ile baraj üzerindeki kontrol noktalarının düşey deformasyonlan arasında bir lineer ilişkinin var olduğunu ortaya koymuştur.Öğe Identification of vertical total electron content by time series analysis(Elsevier, 2009) Erdoğan, Hediye; Arslan, NiyaziTime series analysis of the vertical total electron content (VTEC) is carried out in order to model variations in these observations dependent on time and frequency for various station-satellite pairs. The data of global positioning system (GPS) from four stations are processed in order to obtain the VTEC. The experiment was conducted on two successive days, the 12th and 13th April 2006 (days of year, DOY, 102-103). The mean of the squares of correlation coefficients (R(2)) between time and short-term VTEC is 0.81, which shows high linear correlation for the linear trend component analysis of the time series. For each VTEC observation arc, one significant frequency value is found using the peak-peaking (PP) method in the frequency domain for the periodical component analysis. The stochastic component is modeled with a second-order autoregressive [AR(2)] model. VTEC is recovered by 98% combining trend, periodical and stochastic components. In order to analyze the efficiency of these models for prediction, a 5 min ahead prediction is carried out resulting in a 0.19 mean root mean squared error (RMSE). Also. good results were obtained for 10, 15 and 20 min ahead predictions in some VTEC observation arcs. (c) 2008 Elsevier Inc. All rights reserved.Öğe A GIS-based comparative study of frequency ratio, analytical hierarchy process, bivariate statistics and logistics regression methods for landslide susceptibility mapping in Trabzon, NE Turkey(Elsevier Science Bv, 2011) Yalçın, Ali; Reis, Selçuk; Aydınoğlu, Arif Ça?daş; Yomralıoğlu, TahsinOver the last few decades, many researchers have produced landslide susceptibility maps using different techniques including the probability method (frequency ratio), the analytical hierarchy process (AHP), bivariate, multivariate, logistics regression, fuzzy logic and artificial neural network In addition, a number of parameters such as lithology, slope, aspect, land cover, elevation, distance to stream, drainage density, distance to lineament, seismicity, and distance to road are recommended to analyze the mechanism of landslides. The data quality is a very important issue in landslide studies, and more accurate results will be achieved if the data is adequate, appropriate and drawn from a wide range of parameters. The aim of this study was to evaluate the susceptibility of the occurrence of landslides in Trabzon province, situated in north east Turkey. This was achieved using the following five methods the frequency ratio model, AHP, the statistical index (Wi), weighting factor (Wf) methods, and the logistics regression model, incorporating a Geographical Information System (GIS) and remote sensing techniques. In Trabzon province there has been an increasing occurrence of landslides triggered by rainfall. These landslides have resulted in death, significant injury, damage to property and local infrastructure and threat of further landslides continues. In order to reduce the effects of this phenomenon, it is necessary to scientifically assess the area susceptible to landslide. To achieve this, landslide susceptible areas were mapped the landslide occurrence parameters were analyzed using five different methods. The results of the five analyses were confirmed using the landslide activity map containing 50 active landslide zones. Then the methods giving more accurate results were determined. The validation process showed that the Wf method is better in prediction than the frequency ratio model, AHP, the statistical index (Wi), and logistics regression model. (C) 2011 Elsevier By. All rights reserved.Öğe Analyzing land use/land cover changes using remote sensing and GIS in Rize, North-East Turkey(Molecular Diversity Preservation İnternational-Mdpi, 2008) Reis, SelçukMapping land use/land cover (LULC) changes at regional scales is essential for a wide range of applications, including landslide, erosion, land planning, global warming etc. LULC alterations (based especially on human activities), negatively effect the patterns of climate, the patterns of natural hazard and socio-economic dynamics in global and local scale. In this study, LULC changes are investigated by using of Remote Sensing and Geographic Information Systems (GIS) in Rize, North-East Turkey. For this purpose, firstly supervised classification technique is applied to Landsat images acquired in 1976 and 2000. Image Classification of six reflective bands of two Landsat images is carried out by using maximum likelihood method with the aid of ground truth data obtained from aerial images dated 1973 and 2002. The second part focused on land use land cover changes by using change detection comparison (pixel by pixel). In third part of the study, the land cover changes are analyzed according to the topographic structure (slope and altitude) by using GIS functions. The results indicate that severe land cover changes have occurred in agricultural (36.2%) (especially in tea gardens), urban (117%), pasture (-72.8%) and forestry (-12.8%) areas has been experienced in the region between 1976 and 2000. It was seen that the LULC changes were mostly occurred in coastal areas and in areas having low slope values.Öğe Identification of dynamic systems using Multiple Input-Single Output (MISO) models(Elsevier, 2009) Erdogan, H.; Gülal, E.System identification is a method used to obtain the modal characteristics of existing structural systems through dynamic observations. Modal characteristics of the system can be used for a variety of purposes, including model updates, damage assessment, active control and original design re-evaluation. In this paper, the transfer functions relating the input quantities (traffic load, wind speed and temperature variations) and output quantities (lateral and longitudinal movement) of the towers of the Bosphorus Suspension Bridge were defined with the help of two models, namely, the parametric Multiple Input-Single Output (MISO) Auto-Regressive with eXogenous input (ARX) and the multiple regression models. The latter model was primarily used to check for the existence of outlier measurement(s) and to identify the input quantities that have a significant contribution to the structural movements since outlier measurements in observations and insignificant input quantities increases the difficulty of defining the parameters of the inherently complex MISO ARX model. Least Squares (LS) and bi-square weighted robust predictors were used to determine the parameters of the multiple regression model used in this study. Regression analysis showed that there were no outlier measurements in the tower observations and the effect of wind speed on the longitudinal movements was statistically insignificant. Furthermore, the sensitivity of LS and bi-square robust predictors to outlier measurements were also checked in the regression analysis by adding rough errors to the observations. Finally, it was also observed that the MISO ARX512, ARX511, ARX411 and ARX415 models defined by taking into account the results of regression analysis estimate structural movements more accurately than the multiple regression model ARX010. (C) 2008 Elsevier Ltd. All rights reserved.
