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  Subjects -> GEOGRAPHY (Total: 493 journals)
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Journal of Geodesy and Geoinformation
Number of Followers: 2  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2147-1339 - ISSN (Online) 2667-8519
Published by UCTEA Homepage  [1 journal]
  • Determination of the most suitable wind power plant locations with
           geographical information systems: Kocaeli province example

    • Authors: Serdar EKİZ; Ahmet ŞİRİN, Arzu ERENER
      Abstract: In their lifetime, people need the energy to fulfill their needs. Beforehand, production of energy and, in parallel, the determination of the areas where the energy will be produced has gained importance. In this study, the most suitable site research was carried out in the Geographic Information Systems (GIS) for the construction of wind power plants (WPP) for the environment. It obtains electrical energy by using wind energy, which is one of the renewable energy sources. First of all, 13 factors that have an impact on the WPP site selection process were determined based on similar studies conducted in the past, these are; wind speed, protected areas, bird migration routes, transformer centers, power transmission lines, residential areas, highways, fault lines, elevation, slope, streams, lakes and airports. These determined factors are divided into 6 score classes, ranging from 0 (not suitable) to 5 (extremely appropriate). Then, a mask area map was created by separating the areas in the score class (0) not suitable for WPP from the areas in the other score class. With the mask area map obtained, suitable and unsuitable areas for WPP were clearly determined. The weighted overlay method was used to classify the suitable areas according to their degree of suitability. While applying the weighted overlay method, the weights of the factors with respect to each other were determined in two different ways. In the first study, the factors were weighted and overlapping analysis was performed by using the Analytical Hierarchy Process (AHP), which is one of the Multi-Criteria Decision Analysis (MCDA) methods. In the second study, weighted overlapping analysis was applied by accepting the factors as equally weighted. By overlapping the maps obtained as a result of two different analyzes with the masking area, WPP suitability maps for Kocaeli were obtained. Area calculations were made for the suitability classes over the resulting suitability maps and the two methods were compared with each other. As a result of this study, which was carried out on the entire province of Kocaeli, the most suitable areas where WPP could be established were determined by using GIS and AHP.
      PubDate: Sun, 01 May 2022 00:00:00 +030
       
  • Investigation on the generation of bathymetric maps by combining
           Sentinel-2 imagery and ICESat-2 ATL03 photon height data

    • Authors: Mehmet Güven KOÇAK
      Abstract: Bathymetry maps can be produced with high accuracy by using active acoustic and laser sensing systems. Various acoustic systems such as side-scan sonar, single and multi-beam echosounder are difficult to operate in shallow waters, and measurement with laser systems depends on the presence of appropriate optical transparency. Disadvantages such as workload, time, and economic costs should also be mentioned in the implementation of the two systems. On the other hand, bathymetry maps can be obtained in shallow waters up to a depth of 15 m at an affordable cost with multispectral images covering larger areas and remote/inaccessible locations. This method, known as the experimental approach, requires however sufficient field depth data. In this study, bathymetric map of a study area was generated by combining external depth measurements obtained from ICESat-2 ATL03 photon heights and Sentinel-2 multispectral images. This study aimed to test the accuracy of this bathymetric map against an existing map. Reflectance values measured in Sentinel-2’s coastal aerosol, blue and green bands were modelled under multiple linear regression by using both log-linear and log-rational approaches, and as a result a relative depth map was obtained. The resultant non-metric map is scaled by refraction corrected ICESat-2 depth values building the model’s training set. The bathymetry map was calculated with the multiple linear regression model obtained from this training set and compared with the existing side-scan sonar bathymetric map of the test area. The comparison tests revealed that the atmospheric correction did not improve the results, and better accuracy values were achieved with the log-linear approach compared to the log-rational approach. A root mean square error of ±1.6 m was calculated from the comparisons to the acoustic bathymetry map. The number of differences having absolute values of 5 m and below constituted 94% of the total comparison points. Although the expected accuracy for navigation is not met, bathymetric maps of shallow areas with high optical transparency can still be obtained at a low cost by combining two independent satellite-based datasets for research and other applications.
      PubDate: Sun, 01 May 2022 00:00:00 +030
       
  • Analysis of soil moisture in semi-arid areas with multi-temporal
           RADARSAT-2 data

    • Authors: Sevinç MADENOĞLU; Hesna ÖZCAN, Murat REMZİ, Melis Özge PINAR, Suat AKGÜL, Mehmet KEÇECİ, Tülay TUNÇAY, Mahmut Hilmi SEÇMEN, Ali KOÇ, Mustafa ÜSTÜNER, Aliihsan ŞEKERTEKİN, Saygin ABDİKAN, Mustafa Tolga ESETLİLİ, Aynur SENSOY, Şinasi KAYA, Günay ERPUL, Füsun BALIK ŞANLI
      Abstract: Soil moisture content is a very important factor in terms of energy exchange and water cycle on Earth and has a great impact in many areas regarding assessment of natural risks, hydrology, ecology, agriculture, and climate science. Soil moisture can greatly change spatially and temporally, especially depending on land use changes, and the changing soil moisture may cause various environmental and ecological problems. In this respect, it is an important research subject to examine the spatial change of soil moisture content on large scales. Synthetic Aperture Radar (SAR) sensors play an important role in detecting soil moisture because they are sensitive to soil moisture and they cover large areas. In this study, it was aimed to investigate the determination of the spatial and temporal variation of soil moisture content using fully polarimetric RADARSAT-2 images in wheat cultivated field and fallow land located in The General Directorate of Agricultural Enterprises Gözlü Agricultural Enterprise. The in-situ measurements obtained monthly from field surveys between March and October 2016 were compared with the backscatter values of SAR images. As a result of the study, negative and positive correlation coefficients varying from -0.65 to 0.67 were obtained between backscatter values and in-situ soil moisture values. The highest correlations for soil moisture were obtained in the cultivated area during the May-June period, which is the growing stage of wheat, and the best results for both areas were determined with VV polarimetric data.
      PubDate: Sun, 01 May 2022 00:00:00 +030
       
  • Current situation of national and local CORS networks in Turkey, standards
           and their integration

    • Authors: Ömer GÖKDAŞ; Mustafa Tevfik ÖZLÜDEMİR
      Abstract: Turkey's National Permanent GNSS Network-Active (TUSAGA-Active) that has been started to use since 2009 is currently the most widely used geodetic infrastructure element in point positioning in Turkey. In addition to this network operating with the network RTK principle, there are also local Continuously Operating Reference Stations (CORS) networks in our country, which are mainly operated by local governments and a small number of private sector organizations. These networks, which are used nationally and locally, are used effectively in scientific studies as well as in basic engineering works. Integration of local networks in the axis of standards to be defined with the national TUSAGA-Active network is an important issue that should be on the agenda of our country's geodesy community. In this study, CORS networks established at national and local levels in different countries, and examples of the developed standards are given, the current situation in Turkey and contribution of local networks to the scientific studies are discussed. The studies conducted for the comparison of national and local CORS networks were examined, emphasizing the importance of distance between stations in determining the positioning. In this context, the contribution of local networks to the national network has been demonstrated. In this framework, it has been evaluated that shortening the baseline lengths as a result of integration and thus increasing the point density may contribute positively to the network solution quality. However, in order to achieve this development, it is recommended that the development of standards for the design and operation of CORS networks established locally in our country should be addressed with priority.
      PubDate: Sun, 01 May 2022 00:00:00 +030
       
  • An analysis of international geospatial information models for urban
           utility networks

    • Authors: Azer İLGAR; Volkan ÇAĞDAŞ
      Abstract: Utility networks consist of physical constructions which transport utility service products such as power, water, gas and telecommunication. The pressure of urban population growth increases the density of urban underground areas, moreover, privatization of utilities increases decentralization and fragmentation in the utility sector. Geographic information related to utility networks are mainly held in various formats by utility organizations for operation and asset management activities. Integration and information exchange of utility data are required for numerous activities, namely design, construction and repair of utility networks, disaster planning, emergency response. The differences in data models and information systems limit the ability of integration of different utility data, as well as information exchange among relevant parties such as utility companies, local authorities and other public bodies. Several national and international standardization organizations develop data models and/or data exchange methods that focus on the needs for different use cases which require geospatial data exchange. This paper examines international data models for sharing and exchange of utility network data. It is emphasized that there is no international data model addressing the needs of all use cases, while the models’ content, scope, functionality, and geographic representation capabilities depend on the use cases they focus on.
      PubDate: Sun, 01 May 2022 00:00:00 +030
       
  • ITRF96-ED50 Conversion: Radial basis interpolation and modelling with
           spherical harmonics

    • Authors: İlke DENİZ; Şenol Hakan KUTOĞLU, Rasim DENİZ
      Abstract: Datum transformation is carried out directly by geometric relations between the coordinates of common points or by gridding or modeling the coordinate differences of common points. In this study, to obtain a grid frame using 2591 common point data, the inverse distance weighted interpolation method and spherical harmonic functions modeling method are applied and the accuracies of these methods are determined with 25 control points. Before the evaluations, the trend in the data has been largely eliminated by “Standard Molodensky Transformation”. A grid frame of 15′x15′ from 66x20 = 1320 points is generated by the inverse distance weighted interpolation of the original data. Using this frame, the accuracy of the datum parameters derived from the inverse distance weighted interpolation of the control points is found to be ± 0.225 m for longitude and ± 0.189 m for latitude. The precision of the spherical harmonic functions modeling of the original data is obtained as ±0.035″ (~0.84 m) for longitude and ±0.0245″ (~0.76 m) for latitude. Gridded data is also modeled with spherical harmonic functions. The precision of this modeling is found to be ±0.0177″ (~0.424 m) for longitude and ±0.0129″ (~0.398 m) for latitude. Using this model, the datum parameters of the control points are calculated. The accuracy of the datum parameters of the control points is found to be ±0.38 m for longitude and ±0.28 m for latitude.
      PubDate: Sun, 01 May 2022 00:00:00 +030
       
 
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