Unmanned aerial vehicles (UAV) have been used in a variety of fields in the last decade. In forestry, they have been used to estimate tree heights and crowns with different sensors. This approach, with a consumer-grade onboard system camera, is becoming popular because it is cheaper and faster than traditional photogrammetric methods and UAV-light detecting and ranging systems (UAV-LiDAR). In this study, UAV-based imagery reconstruction, processing, and local maximum filter methods are used to obtain individual tree heights from a coniferous urban forest. A low-cost onboard camera and a UAV with a 96-cm wingspan made it possible to acquire high resolution aerial images (6.41 cm average ground sampling distance), ortho-images, digital elevation models, and point clouds in one flight. Canopy height model, obtained by extracting the digital surface model from the digital terrain model, was filtered locally based on the pixel-based window size using the provided algorithm. For accuracy assessment, ground-based tree height measurements were made. There was a high 94% correlation and a root-mean-square error of 28 cm. This study highlights the accuracy of the method and compares favourably to more expensive methods.
ABSTRACT:Water resources are getting more and more important with each passing day in case of survival of humanity. For this reason, assessing water resources' quality and also monitoring them have attracted lots of attention in the recent years. Remote sensing has been growing widely in the last decade and its resources are very usable when it comes to water resources management. In this study, by using remote sensing technology, satellite images that have 350 to 1050 nanometres wavelength band sensors (e.g. CHRIS Proba) are used to determine the quality of the Kizilirmak River's water. Kizilirmak River is born and also pours out to sea in country limits of Turkey. It is the longest river of the country by the length of 1355 kilometres. Through the river's resources, ground based spectral measurements are made to identify the quality differences of the water at the test spots that have been determined before. In this context at Imranli, where the river contacts civilization for the first time, which is located in Sivas city of Turkey, samples are gathered in order to do ground based spectroradiometer measurements. These samples are gathered simultaneously with the image acquiring time of CHRIS Proba satellite. Spectral signatures that are obtained from ground measurements are used as reference data in order to classify CHRIS Proba satellite's hyperspectral images over the study area. Satellite images are classified based on Chemical Oxygen Demand (COD), Turbidity and Electrical Conductivity (EC) attributes. As a result, interpretations obtained from classified CHRIS Proba satellite hyperspectral images of the study area are presented.
Climate is one of the most important factors that enable the existence of life on Earth. The climate has been studied by many scientists throughout the history for its influence on all living and non-living beings. Researchers have used climatological parameters (temperature, humidity, rainfall, sunshine duration, evapotranspiration etc.) with different approaches and created a variety of methods. When putting these classifications into consideration, they have taken different criteria into account and have produced different classification. Some of these formulas are short and simple, some are very long and complex. Using these formulas, researchers have determined different climatic types suited to different regions. In this study, two separate climate classification methods were used (Erinç and De Martonne). Meteorological data ranging from 1980 to 2011 were examined periodically and arranged according to determined classification methods. The data were processed in accordance with De Martonne and Erinç classification formulas by GIS and the climate change of İzmir province has been revealed between 1980-1989 and 2006-2011 time periods.
Unmanned Aerial Vehicles (UAVs) are successfully used in many different fields such as military, forest fire, archaeological sites, agricultural applications, traffic control, radiation monitoring, natural disasters, urban management etc. At the same time, UAVs are extremely important tools for achieving accurate and up-to-date information quickly and economically. Today, UAVs can stay in the air for up to about 3.5 hours, and during this time they can take in aerial images that can produce ortho-images of an area of about 15 square kilometers. All of these features make UAV the tool of professional land surveying and ortho-image production that is fast, accurate and easy to use. The most important basic component in Geographical Information Systems (GIS) is geographical data. UAVs which produces this data quickly and accurately, are one of the most important data collection methods. In recent years, it has been utilized effectively from the production of ortho-images used as basic data in GIS. In this study, the data obtained from the UAV at the study area of Cumhuriyet University Campus (Sivas city, Turkey) were evaluated with the photogrammetric data evaluation software Pix4D and the Digital Terrain Model (DTM) and ortho-images were produced. By interpreting these products, geographical layers such as buildings, electric poles, roads and manholes related to the campus were created on the GIS environment and the infrastructure of the Campus Information System (CIS) was established. Thus, a inquirable and analysable GIS-based system has been created to contribute to the management and planning activities to be carried out on the campus. As a result, UAV photogrammetry is a fast and easy to get economic geographical data for GIS-based studies, and is a tool for updating these systems in efficient times to provide effective and productive results and updates to information systems.
Hydrothermal alteration is one of the most important steps in the exploration of precious ore deposits. In this study, it is aimed to detect the hydrothermal alteration areas and mineral contents they preserve with ASTER and Hyperion satellite images and compare the obtained results. Because of the presence of intensive hydrothermal alteration and poor vegetation, the area which is located at the northern part of Zara district of Sivas Province has been chosen as the study area. Contact zones of Argillic (Kaolinite, illite), phyllic (serisite, muscovite) and propylitic (chlorite, calsite, epidote) alteration areas were detected with field studies, petrographic and geochemical investigations. The spectral signatures of hydrothermal minerals were measured via ASD spectroradiometer from the representative samples belonging to hydrothermal alteration study areas. According to the results, obtaining the hydrothermal alteration maps from ASTER and Hyperion satellite data are in coincide with the geological map.
Arazi uygunluk analizi, en uygun arazi kullanımı amacına yönelik arazi kullanımının esaslarını belirleyen bileşenlerden biridir. En uygun arazi kullanımı, bölgeye ait topografik etmenler ve tarımsal veriler ışığında, çiftçi alışkanlıkları ile bölgenin doğal ve kültürel potansiyeli dikkate alınıp ekolojik esaslar gözetilerek hazırlanan bir arazi kullanımının tercih edilmesi ile sağlanır. Bu çalışmada en uygun arazi kullanım planlanmasının CBS ile belirlenmesine yönelik bir uygulama gerçekleştirilmiştir. Sivas İli Merkez İlçe Dikmencik köyüne ait kadastral sınırlar içerisinde yer alan tarımsal alanlar ile mera ve orman arazileri olmak üzere üç ana sınıflandırmaya tabii tutulan arazilerin arazi kullanım biçimleri dikkate alınmıştır. Daha sonra, en uygun arazi kullanım haritaları üretilmiş ve sonuçlar günümüzdeki mevcut arazi kullanım özellikleri ile karşılaştırılmıştır. Elde edilen sonuçlara göre çalışma alanındaki arazilerin büyük bir bölümünün en uygun arazi planlamasına uygun bir şekilde kullanılmadığı tespit edilmiştir.
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