Saffet Erdogan

Geographical information systems aided traffic accident analysis system case study: city of Afyonkarahisar.

Geographical Information System (GIS) technology has been a popular tool for visualization of accident data and analysis of hot spots in highways. Many traffic agencies have been using GIS for accident analysis. Accident analysis studies aim at the identification of high rate accident locations and safety deficient areas on the highways. So, traffic officials can implement precautionary measures and provisions for traffic safety. Since accident reports are prepared in textual format in Turkey, this situation makes it difficult to analyze accident results. In our study, we developed a system transforming these textual data to tabular form and then this tabular data were georeferenced onto the highways. Then, the hot spots in the highways in Afyonkarahisar administrative border were explored and determined with two different methods of Kernel Density analysis and repeatability analysis. Subsequently, accident conditions at these hot spots were examined. We realized that the hot spots determined with two methods reflect really problematic places such as cross roads, junction points etc. Many of previous studies introduced GIS only as a visualization tool for accident locations. The importance of this study was to use GIS as a management system for accident analysis and determination of hot spots in Turkey with statistical analysis methods.

Explorative spatial analysis of traffic accident statistics and road mortality among the provinces of Turkey.

INTRODUCTION The aim of the study is to describe the inter-province differences in traffic accidents and mortality on roads of Turkey. METHOD Two different risk indicators were used to evaluate the road safety performance of the provinces in Turkey. These indicators are the ratios between the number of persons killed in road traffic accidents (1) and the number of accidents (2) (nominators) and their exposure to traffic risk (denominator). Population and the number of registered motor vehicles in the provinces were used as denominators individually. Spatial analyses were performed to the mean annual rate of deaths and to the number of fatal accidents that were calculated for the period of 2001-2006. Empirical Bayes smoothing was used to remove background noise from the raw death and accident rates because of the sparsely populated provinces and small number of accident and death rates of provinces. Global and local spatial autocorrelation analyses were performed to show whether the provinces with high rates of deaths-accidents show clustering or are located closer by chance. The spatial distribution of provinces with high rates of deaths and accidents was nonrandom and detected as clustered with significance of P<0.05 with spatial autocorrelation analyses. RESULTS Regions with high concentration of fatal accidents and deaths were located in the provinces that contain the roads connecting the Istanbul, Ankara, and Antalya provinces. Accident and death rates were also modeled with some independent variables such as number of motor vehicles, length of roads, and so forth using geographically weighted regression analysis with forward step-wise elimination. The level of statistical significance was taken as P<0.05. Large differences were found between the rates of deaths and accidents according to denominators in the provinces. The geographically weighted regression analyses did significantly better predictions for both accident rates and death rates than did ordinary least regressions, as indicated by adjusted R(2) values. Geographically weighted regression provided values of 0.89-0.99 adjusted R(2) for death and accident rates, compared with 0.88-0.95, respectively, by ordinary least regressions. IMPACT ON INDUSTRY Geographically weighted regression has the potential to reveal local patterns in the spatial distribution of rates, which would be ignored by the ordinary least regression approach. The application of spatial analysis and modeling of accident statistics and death rates at provincial level in Turkey will help to identification of provinces with outstandingly high accident and death rates. This could help more efficient road safety management in Turkey.

Modelling the spatial distribution of DEM error with geographically weighted regression: An experimental study

Digital elevation models are digital representations of topography and are the principal digital data source for many disciplines. The accuracy of a digital elevation model is particularly important with its intended use. The assessment of accuracy is usually undertaken by deriving some measures of indices. These indices are usually global indices and summarise the accuracy. In this study, a more detailed accuracy is discussed by examining the magnitudes and spatial patterning of elevation errors. Many researches have demonstrated the effects of interpolation methods and the nature of errors in digital elevation models for small-scale areas. On the contrary, this study investigated the size and spatial patterning of errors in a large-scale area, by comparing three different interpolation algorithms. This research also examined the accuracy related with data density and surface characteristics at the field scale. Finally, ordinary least squares and geographically weighted regression models were used to model the relationship between error and surface characteristics. Geographically weighted regression modelling gave better results than ordinary least-squares regression modelling.

GPS Velocity and Strain Rate Fields in Southwest Anatolia from Repeated GPS Measurements

Southwestern Turkey is a tectonically active area. To determine kinematics and strain distribution in this region, a GPS network of sixteen stations was established. We have used GPS velocity field data for southwest Anatolia from continuous measurements covering the period 2003 to 2006 to estimate current crustal deformation of this tectonically active region. GPS data were processed using GAMIT/GLOBK software and velocity and strain rate fields were estimated in the study area. The measurements showed velocities of 15–30 mm/yr toward the southwest and strain values up to 0.28–8.23×10−8. Results showed that extension has been determined in the Burdur-Isparta region. In this study, all of strain data reveal an extensional neotectonic regime through the northeast edge of the Isparta Angle despite the previously reported compressional neotectonic regime. Meanwhile, results showed some small differences relatively with the 2006 model of Reilinger et al. As a result, active tectonic movements, in agreement with earthquake fault plane solutions showed important activity.

Modeling crop yield potential of Eastern Anatolia by using geographically weighted regression

Wheat is a very important cereal crop in Eastern Anatolia in terms of acreage and production. It is a staple food and plays an important role in peoples livelihood. Drought often occurs in the region and it dramatically influences wheat yield. The yield also depends upon prevailing climatic conditions, rainfall, temperature and humidity. Crop-modeling studies to forecast crop yield are important not only for people now but for planning studies and precautionary measures for the future. Traditional decision support systems based on crop simulation models are normally site-specific. In order to address the effect of spatial variability of weather variables on crop production, we modeled wheat yield potential on certain climatic conditions by using Geographically Weighted Regression and Geographical Information Systems in Eastern Anatolia in Turkey.

Monitoring of Deformations Along Fethiye-Burdur Fault Zone (Turkey) with GPS

Afyonkarahisar, Burdur and Fethiye region, southwest of Turkey is located on a tectonically active area. According to the historical recordings, the region was destructed by earthquakes many times. Since the beginning of the 20th century, more than 35 earthquakes with magnitudes bigger than 4 occurred in Afyonkarahisar region. Seven earthquakes recorded over the last 90 years in the region between Burdur and Fethiye whose magnitudes are between 5.0 and 7.0. This new project “Monitoring of Deformations Along Fethiye-Burdur Fault Zone With GPS”, is founded by The Scientific and Technical Research Council of Turkey (TUBITAK), Istanbul Technical University (ITU), Karadeniz Technical University (KTU) and Afyon Kocatepe University (AKU). The aim of the project is to determine strain accumulation of the study area.

The determination of relations between statistical seismicity data and geodetic strain analysis, and the analysis of seismic hazard in southwest Anatolia

This study aims the relations between seismicity data and strain analysis based on geodetic space techniques in order to define the seismicity hazard of the southwest Anatolian region of Turkey. This region has complex tectonic formations and requires sophisticated techniques and approaches to investigate seismic activities. In this study, global navigation satellite system (GNSS) observations were used to determine the velocity field of the region. The strain rates of the region were obtained from the evaluation of this velocity field. In addition, seismicity b parameters of the region were calculated from the analysis of seismicity data. Furthermore, the seismicity data and the geodetic strain rates obtained from the GNSS observations were combined to show the statistical correlation. This correlation was interpreted to define the seismicity. According to the results derived from the correlation analysis, the geodetic strain analysis and seismicity data were highly and inversely correlated (r = −0.96). After the determination of the correlation, the seismic hazard data of the region was added to the analysis. This process shows that seismic hazards are highly and negatively correlated to seismicity data (r = −0.90), even though they are highly but positively correlated to geodetic strain analysis (r = 0.88).

3 Boyutlu Bina Modelleme ve WEB Tabanlı Sunumu: Ahmet Necdet Sezer Kampüsü Örneği

The developments in technology in recent years have provided significant opportunities in the collection, processing and presentation of data. 3D‐modeling has been used in various areas; such as, virtual reality, virtual tours in the panoramic images, tourism and even virtual museums. In particular, the 360° panoramic tours have an increasing use in the promotional purposes and tourism in recent years. Places and locations are presented to users through virtual tours on the web. This study is realized in accordance with current base map of Ahmet Necdet Sezer (ANS) campus. All buildings in campus have been modeled in 3D and facedes were covered with real textures. The generated models have been transferred in to Google Earth. Moreover, the streets map of ANS campus has also been transferred in to web for virtual trip.

Türkiye'de Buğday (T. aestivum L.) Ekim Alanı, Üretim ve Veriminin Krigging Yöntemi ile Değerlendirmesi

The purpose of this study was to reveal similarities and dissimilarities of provinces and to determine the potential of provinces on wheat in terms of for acreage, production and yield by using krigging method in Turkey. Wheat is the most important and strategic crop for Turkey and plays important a role in crop production, food industry and animal husbandry whether it is given greater importance in production marketing and valorization. Results revealed that, significant relationships appear between acreage, production and crop yield. Besides, climatic, topographic and soil conditions are very significant factors in determining acreage, yield and production of wheat. The use of cultivars having higher yield, more tolerance to drought cold, and have a shorter growing period allowing rapid development will increase crop, yield therefore acreage and production.