Ugur Alganci

Istanbul Technical University · Department of Geomatics Engineering

The use of satellite imagery in critical areas, such as environmental monitoring and natural disaster management, is becoming increasingly important. Applications like monitoring coastal areas, detecting coastal erosion, and tracking land use changes demand high accuracy and detailed analysis. Traditional methods for coastline segmentation are ofte...

Future simulations of land use and land cover (LULC) are required to effectively manage patterns of interactions between land use classes due to ambitious sustainability goals and integrated urban planning policies. This study investigates the performance and suitability of two simulation models, artificial neural networks (ANN) and Logistic Regres...

Wildfires have become a growing global concern due to the environmental and economic damage they cause. Climate change is a primary cause of wildfires as it increases the frequency, extent, and severity of wildfires. In addition to climate change, human activities have become a major cause of wildfires, particularly in the Mediterranean region. Sin...

Compared to natural images in artificial datasets, it is more challenging to improve the spatial resolution of remote sensing optical image data using super-resolution techniques. Historical aerial images are primarily grayscale due to single-band acquisition, which further limits their recoverability. To avoid data limitations, it is advised to em...

Land use / Land cover Urban heat islands Random Forest Google Earth Engine Change detection Global and local population growth and the rapid increase in urbanization affect nature negatively by the destruction on forests and natural lands. An additional problem can be considered as the increment of the land surface temperatures due to the heat isla...

Google Earth Engine ERA 5 Temperature Türkiye The climate system involves complicated interactions among diverse atmospheric and environmental elements, and it is essential to comprehend prolonged temperature trends for evaluating the consequences of climate change. In this study, an analysis of temperature changes in Türkiye over the period from 2...

For more than 50 years, marine and remote sensing researchers have investigated the methods of bathymetry extraction by means of active (altimetry) and passive (optics) satellite sensors. These methods, in general, are referred to as satellite-derived bathymetry (SDB). With the advances in sensor capabilities and computational power and recognition...

Satellite images have been widely used in the production of geospatial information such as land use and land cover mapping and the generation of several thematic layers via image processing techniques. The systematic sensor and platform-induced geometry errors influence images acquired by sensors onboard various satellite platforms. Thus, geometric...

Bathymetric mapping is essential for understanding ocean dynamics, mapping ecosystems, and forecasting coastal erosion. The goal of this study is to produce bathymetric models in shallow coastal area of rarely investigated Antarctic region using machine learning methods and Sentinel-2 satellite image. Based on satellite imagery and multibeam echoso...

Satellite-derived bathymetry (SDB) is the process of estimating water depth in shallow coastal and inland waters using satellite imagery. Recent advances in technology and data processing have led to improvements in the accuracy and availability of SDB. The increased availability of free optical satellite sensors, such as Landsat missions and Senti...

The measured ocean floor sits at 25%, less than the face of Mars or Venus. The main reasons for this lack of coverage are the cost and time attached to the traditional method of bathymetric surveys, which is by means of specialized sonars. Alternative approaches have been under the spotlight for the last 10 years in an effort to compensate for this...

Yeryüzündeki değişimin saptanması ve izlenmesi her zaman dikkate değer bir konu olmuştur. Zaman içinde insan faaliyetleri genişlemiş ve arazi örtüsünde bu faaliyetlerin etkisi açıkça görülmüştür. Sanayi faaliyetlerinin artması, yerleşimin fazlalaşması gibi konular nedeniyle arazi örtüsündeki değişimi izlenmesi ve takip edilmesi karar vericiler açıs...

Precipitation is an important component of the hydrological and energy cycles, as well as a key input parameter for many applications in the fields of hydrology, climatology, meteorology, and weather forecasting research. As a result, estimating precipitation accurately is critical. The purpose of this research is to conduct a comprehensive and com...

In recent years, the production of digital elevation models (DEMs) by using the interferometric synthetic aperture radar (InSAR) technique has become more useful compared to traditional methods. When DEM production is carried out by using this technique, an external DEM is used in the image processing steps. In this study, new DEMs were produced fr...

Time series analysis combined with remote sensing data allows for the study of abrupt changes in the environment due to significant and severe disturbances such as deforestation, agricultural activities, fires, and urban expansion, as well as gradual changes such as climate variability and forest degradation in the ecosystem. The precision of any c...

Land cover maps created with remote sensing images are used for observation in many areas such as urban planning, land resources management, and biodiversity changes. The study of land cover change has a very important place in order to properly analyze the rapidly developing urbanization and to make the right city planning due to the increasing po...

The classification of maritime boats and ship targets using optical satellite imagery is a challenging subject. This research introduces a unique and rich ship dataset named Very High-Resolution Ships (VHRShips) from Google Earth images, which includes diverse ship types, different ship sizes, several inshore locations, and different data acquisiti...

Remote sensing Building extraction Deep learning Automated detection Unet Architecture Building extraction from very high-resolution satellite images is an important task due to the various different usage of the extracted information such as population estimation, city planning and disaster management. Manual extraction of the buildings is a labor...

With the recent developments in remote sensing technology, satellite images with high spatial and temporal resolution have been becoming widely available. Very high resolution (VHR) satellite images are very appropriate data sources for geospatial object detection using deep learning algorithms. Airplane detection from satellite images is one of th...

The harmful impacts of fast urbanization and population growth on nature are becoming more pronounced every day. Human demands are growing in tandem with population growth, and the most common solutions advocated to address these needs are agricultural development and urbanization. The increase in urban areas causes a decrease in forest and green a...

Remote sensing data indicates a considerable ability to map post-forest fire destructed areas and burned severity. In this research, the ability of spectral indices, which are difference Normalized Burned Ratio (dNBR), relative differenced Normalized Burn Ratio (RdNBR), Relativized Burn Ratio (RBR), and difference Normalized Vegetation Index (dNDVI...

The traditional way of conducting a hydrographic survey with subject-specific sonars fails to deliver satisfactory results globally; in terms of time, effectiveness, and safety in shallow water zones. Therefore, Satellite-derived Bathymetry applications arose as an alternative approach to the traditional hydrographic surveying methods. In this stud...

This study focused on the determination of maize cultivated lands in Cukurova Basin, Turkey with the object-based classification of Sentinel 2 satellite images assisted with near real-time field campaigns. Cukurova Basin includes one of the biggest agricultural plains of Turkey and ranks first in the production of maize, soybean and pistachio. In a...

Olive, a crucial crop for the economies of Mediterranean countries, is expanded to Aegean, Mediterranean, Marmara, SouthEast and Black Sea regions of Turkey. Identification of olive trees in heterogeneous land surfaces, particularly in mountainous regions is essential for exploitation of un-grafted olive trees. In this study, several samples of oli...

Convolutional neural network (CNN)-based approaches have shown promising results in the pansharpening of the satellite images in recent years. However, they still exhibit limitations in producing high-quality pansharpening outputs. To that end, we propose a new self-supervised learning framework, where we treat pansharpening as a colorization probl...

Pan-sharpening is a fundamental task of remote sensing, aiming to produce a synthetic image having high spatial and spectral resolution of original panchromatic and multispectral images. In recent years, as in other tasks of the remote sensing field, deep learning based approaches have been developed for this task. In this research, a detailed comp...

Günümüzde gelişen uydu teknolojilerine bağlı olarak uydu görüntülerinin mekânsal, spektral ve zamansal çözünürlüğünde önemli seviyede artışlar meydana gelmiştir. Bu artışlar aynı zamanda veri boyutunda ve hacminde artışa ve buna bağı olarak veri paylaşımında zorluklara sebep olmaktadır. Artan veri boyutları, web üzerinden coğrafi verilerin paylaşım...

This study presents a semi-automatic algorithm for mapping floods. Both Optical and Synthetic Aperture Radar (SAR) data are used to observe the flood that hit the Cukurova region of Adana (Turkey) in 2019. The performance of the interferometric coherence in complementing intensity component of SAR data is investigated for mapping the floods occurre...

Convolutional Neural Networks (CNN)-based approaches have shown promising results in pansharpening of satellite images in recent years. However, they still exhibit limitations in producing high-quality pansharpening outputs. To that end, we propose a new self-supervised learning framework, where we treat pansharpening as a colorization problem, whi...

Object detection from satellite images has been a challenging problem for many years. With the development of effective deep learning algorithms and advancement in hardware systems, higher accuracies have been achieved in the detection of various objects from very high-resolution (VHR) satellite images. This article provides a comparative evaluatio...

Recent very high spatial resolution (VHR) remote sensing satellites provide high spatial resolution panchromatic (Pan) images in addition to multispectral (MS) images. The pan sharpening process has a critical role in image processing tasks and geospatial information extraction from satellite images. In this research, CIELab color based component s...

Digitial Surface Model (DSM) is an important spatial data source for several planning, engineering and remote sensing studies such as city planning, 3D city model production, hydrological and geological modelling and monitoring, construction design, image orthorectification and 3D geospatial analysis. High geometric accuracy and level of detail pro...

Improving urban land cover/use classification accuracy has been an essential issue due to growing demand for precise urban mapping, especially for the regions that represent complex land cover in frequently changing urban and pre-urban areas because of ongoing rapid urbanization. The normalized spectral indices were proved reliable information sour...

Index based approaches are proved to improve the performance of land-cover/use (LCLU) determination from satellite images. In addition, spectral indices derived from multi-temporal satellite images enable continuous monitoring of the crops and plants in their growing seasons. Changes on starting time and duration of phenological stages of plants an...

In this research, multi-criteria decision analysis with pairwise comparison weighting method was utilized to determine the suitable locations for vineyard plantation in Sarkoy region of Turkey. Soil maps, meteorological measurements, slope, aspect, elevation maps were used as input to conduct spatial analysis. Different methods were compared and pa...

This research aims to determine the flooded agricultural lands after the flood that occurred in April 2015 on the Menderes Plain. The unexpected heavy and continuous precipitation in spring season induced a flash flood on the Menderes River, which directly damaged the agricultural lands. The flooded areas are determined by geographic object based G...

Global warming, which triggers climatic changes, has direct effects on the phenology of plants. For a sustainable agricultural production, continuous monitoring of crops and trees is critical to have updated information and producing effective agricultural plans. Remote sensing is an efficient option for this purpose and is a very popular technique...

For spatial analyses, raster land cover/use maps are converted into points, where each point holds attribute of its corresponding land cover/use. However, these are not identical in terms of areas or shapes, thus assigning a point to each isolated shape is not an adequate solution and for that gridding is suggested. Square, hexagon and triangle are...

Günümüzde gelişen uydu teknolojilerine bağlı olarak uydu görüntülerinin mekânsal, spektral ve zamansal çözünürlüğünde önemli seviyede artışlar meydana gelmiştir. Bu artışlar aynı zamanda veri boyutunda ve hacminde artışa ve buna bağı olarak veri paylaşımında zorluklara sebep olmaktadır. Artan veri boyutları, web üzerinden coğrafi verilerin paylaşım...

Uncontrolled and continuous urbanization is an important problem in the metropolitan cities of developing countries. Urbanization progress that occurs due to population expansion and migration results in important changes in the land cover characteristics of a city. These changes mostly affect natural habitats and the ecosystem in a negative manner...

Climate change, rapid urbanization and industrialization have so far resulted in substantial loss of agricultural land, forestry and green areas that are environmentally of utmost importance. This is noted considerably in many coastal regions and highly populated cities such as metropolis Istanbul in Turkey. In that sense, there is an urgent need f...

The main objective of this study is to compare the performance of two interpolation approaches, namely Inverse Distance Weighting (IDW) and Ordinary Kriging (OK) methods, for mapping spatial distribution of soil characteristics including electrical conductivity (EC), organic matter, phosphorus, lime and boron in the Tuz Lake Basin of Turkey. A tota...

Rapid and uncontrolled urbanization is one of the most important land cover change phenomenon, which has important environmental impacts on ecosystem and climate. Due to the urbanization, green areas and natural permeable surfaces transform into non-permeable impervious surfaces, yielding an increase in urban land surface temperatures (LST). This c...

Performing point-based land cover/use analysis traditionally compels converting thematic clusters into representative points located at their corresponding centroids. Yet, various spatial analyses require to grid thematic maps into smaller regular geometric grids such as square and triangle, where the attribute of the dominant land cover/use class...

Determination of cotton and maize cultivated areas with multi-temporal satellite images using vegetation indices is the main objective of this research. Study area was located on Sanliurfa province, Turkey, which hosts huge amount of agricultural production of cotton and maize in spring-summer season with its suitable and effective irrigation syste...

In this research work, a multi-index-based support vector machine (SVM) classification approach has been proposed to determine the complex and morphologically heterogeneous land cover/use (LCU) patterns of cities, with a special focus on separating bare lands and built-up regions, using Istanbul, Turkey as the main study region, and Ankara and Kony...

Identification of fruit trees and determination of their spatial distribution is an important task for several agricultural activities including fruit yield estimation, irrigation planning, disease management and supporting agricultural policies. This research aims to determine spatial distribution of olive trees at parcel level by using geographic...

Gelişmekte olan ülkelerde büyük şehirler, nüfus artışı ve göçe bağlı olarak dinamik bir şehirleşme sürecine maruz kalmaktadır. Şehirleşme sürecinin ivmesine bağlı olarak sürekli inşa edilen yerleşim bileşenleri, arazi örtüsü ve kullanımında önemli değişikliklere neden olmaktadır. Bu değişimler genellikle doğal örtü ve ekosistem üzerinde negatif etk...

Raw remotely sensed images contain geometric distortions and cannot be used directly for map-based applications, accurate locational information extraction or geospatial data integration. A geometric correction process must be conducted to minimize the errors related to distortions and achieve the desired location accuracy before further analysis....

Digital elevation models (DEMs), which can occur in the form of digital surface models (DSMs) or digital terrain models (DTMs), are widely used as important geospatial information sources for various remote sensing applications, including the precise orthorectification of high-resolution satellite images, 3D spatial analyses, multi-criteria decisio...

This manuscript presents an on-going research project, where the aim is to develop a Geographic Information System (GIS) based decision making method for supporting the sustainable transportation policies of Istanbul Electricity, Tramway and Tunnel General Management (IETT). The main approach is to design a spatiotemporal model for detecting the in...

Construction projects being carried out in our country, especially road projects, despite all practical benefits, have serious effects on the natural environment. In this study, the effects of the construction of D-020 highway between Sile-Kefken on the natural environment were examined. To investigate the natural land cover change, Landsat 5 and 8...

In this study, the changes in land cover/use is detected using remote sensing, GIS and stochastic modelling for part of metropolitan Istanbul city. The selected area has changed significantly in the last 40 years making it ideal case of study. The followed methodology is as follows. Firstly, five satellite imageries going back to 1975, 1987, 1997,...

Land cover/land use change become an important aspect of global change, because of its interactions with climate, ecosystem processes, biodiversity, and even more human activities. Within city boundaries, areas of arable lands, green and open spaces are dynamically changing according to human activities. Mostly observed is a drop of their areas due...

Soil properties considerably affect sustainability of land use, plant growth, agricultural productivity, and may pose soil compaction risk. Spatial interpolation is very useful to predict unknown values of any geographic location by using limited number of field measurements. Spatial interpolation approaches are extensively used to analyze, predict...

Determination of the cultivated areas and crop types is crucially important in yield estimation and gross agricultural production determination but also considerably essential in terms of environmental monitoring as agricultural activities affect the environment directly by increasing the use of water resources and nutrient loads in soil. Moreover,...

Istanbul is one of the biggest metropolitans around the world. According to Turkish Statistical Institute (TUIK) census database while the population of the city in 1980 was around 4.74 million, in 2016 it reached to 14.8 million. Over three decades, the large-scale growth in population of the city caused to a dramatic increase in urbanisation. Nat...

This research aims to analyze geometric correction accuracy of empirical Rational Function Model (RFM), empirical Rational Polynomial Coefficient (RPC) Refinement Model and physical Toutin Model applied to Very High Resolution (VHR) Pleiades satellite images. Two different pilot regions located in Turkey with different topographic characteristics w...

Günümüzde uydu teknolojilerinin kullanım alanları, gelişen algılayıcı çözünürlüğüne bağlı olarak oldukça genişlemiştir. Ancak uydu görüntülerinin mekansal çözünürlüklerindeki artışa rağmen bu verilerden otomatik bilgi çıkarım sürecinde hala istenilen doğruluğa ulaşılamamıştır. Otomatik bilgi çıkarımında hataların giderilmesi ve görüntülerden yüksek...

Determining the hydroelectric power potential of ungauged or poorly gauged basins gains importance parallel with the increasing electricity consumption. This study presents some simple methods to predict flow to determine the hydroelectric power potential of poorly gauged basins, such as the precipitation-elevation, average precipitation, and avera...

Determining physical parameters of a watershed is essential to understand its structure, to assess the hydrological processes and to well-define the negative pressures on it. Linear and areal morphological parameters enable scientists to acquire quantitive data, and thus fundamental information that is required in planning and managment of the wate...

Turkey is divided into 25 hydrologic basins depending on the topographic structure. These basins have different productivities and potentials in relation with the annual rainfall they receive. Among them, Firat-Dicle Basin that constitutes approximately 47.7% of the water potential of the whole country, takes the first place in terms of water produ...

Bu çalışma kapsamında ulaşım sisteminin temel ürünü olan erişilebilirlik ve arazi kullanımı etkileşimi belirlenerek farklı senaryoların test edilmesini sağlamak üzere İstanbul için tasarlanan ve halen yürütülen araştırma projesi tanıtılacaktır. Sürdürülebilir ulaştırma politikalarını desteklemek üzere tasarlanan sistem, Coğrafi Bilgi Sistemleri (CB...

In this study, topographic, hydrologic and land use/cover parameters of Melen Watershed, Turkey, were determined using remote sensing and GIS techniques. Melen Watershed located in Duzce Province supplies an important amount of water demand of the megacity Istanbul. Initially, height, slope and aspect maps of the watershed were determined using AST...

In this study, topographic, hydrologic and land use/cover parameters of Melen Watershed, Turkey, were determined using remote sensing and GIS techniques. Melen Watershed located in Duzce Province supplies an important amount of water demand of the megacity Istanbul. Initially, height, slope and aspect maps of the watershed were determined using AST...

Main focus of this study is to determine the destructions and infractions in forest areas of Istanbul, Turkey using multi-temporal Landsat satellite imagery. Analysis was mainly constructed on supervised classification of multi-temporal satellite images. Determined changes were exported to GIS and spatial overlay and intersection analyses were perf...

ABSRACT: In this study, vegetation changes in 39 Istanbul districts of between 1984 and 2011 were analyzed using Landsat 5 TM satellite sensor images. Satellite sensor images were registered to each other in order to ensure the locational and geometric accuracy in multi-temporal analysis. In the next step, Normalized Difference Vegetation Index (ND...