Dimitrios D. Alexakis

Dimitrios D. Alexakis
Foundation for Research and Technology - Hellas | forth · Institute for Mediterranean Studies Geophysical - Satellite Remote Sensing and Archaeo-environment Laboratory (GeoSat ReSeArch Lab)

Assistant Researcher (Assistant Professor)Foundation for Research and Technology Hellas (FORTH)

About

136
Publications
53,255
Reads
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2,108
Citations
Introduction
Dr. Dimitrios Alexakis has received his Ph.D in 2009 from the Aristotle’s University of Thessaloniki (School of Geology). He is currently an Assistant Researcher (Assistant Professor level) at the GeoSAT ReSeArch Lab, Institute for Mediterranean Studies, Foundation for Research and Technology Hellas (IMS/FORTH). His research interests include Satellite remote sensing, GIS, Geomorphology, Landscape ecology, UAV, Landscape Archaeology, Field spectroscopy, Hydrology and applications of Geoinformati
Additional affiliations
December 2018 - December 2021
Foundation for Research and Technology - Hellas
Position
  • Professor (Assistant)
August 2014 - present
Technical University of Crete
Position
  • PostDoc Position
January 2014 - July 2014
Foundation for Research and Technology - Hellas
Position
  • PostDoc Position
Education
December 2003 - June 2009
Aristotle University of Thessaloniki
Field of study
  • School of Geology (Remote Sensing and GIS
November 2001 - October 2003
Aristotle University of Thessaloniki
Field of study
  • School of Geology
October 1996 - October 2001
Aristotle University of Thessaloniki
Field of study
  • School of Geology

Publications

Publications (136)
Article
Full-text available
Shallow bathymetry mapping using proximal sensing techniques is an active field of research that offers a new perspective in studying the seafloor. Drone-based imagery with centimeter resolution allows for bathymetry retrieval in unprecedented detail in areas with adequate water transparency. The majority of studies apply either spectral or photogr...
Preprint
Short-term changes in shallow bathymetry affect the coastal zone and therefore their monitoring is an essential task in coastal planning projects. This study provides a novel approach for monitoring shallow bathymetry change based on drone multispectral imagery. Particularly we apply a shallow water inversion algorithm on two composite multispectra...
Conference Paper
Full-text available
This study explores the potential use of integrated radar and optical freely and open access distributed satellite images, namely the Sentinel-1 and Sentinel-2, respectively, to detect areas with archaeological interest. The Google Earth Engine platform was used to extract the backscattering signal from the Sentinel-1 sensor and the reflectance val...
Book
Full-text available
The publication of this Handbook is a direct result of the European project “Digital Educational Geoinformatic Methodologies for Monitoring Landscape – GEOLAND”. It was prepared by the project consortium with partners from Greece, Belgium, Spain, Italy, and Bulgaria. The project is co-funded by the Erasmus+ Programme of the European Union (EU).
Article
Full-text available
Shallow bathymetry inversion algorithms have long been applied in various types of remote sensing imagery with relative success. However, this approach requires that imagery with increased radiometric resolution in the visible spectrum be available. The recent developments in drones and camera sensors allow for testing current inversion techniques...
Preprint
Full-text available
Shallow bathymetry inversion algorithms have long been applied in various types of remote sensing imagery with relative success. However, this approach requires that imagery with increased radiometric resolution in the visible spectrum is available. The recent developments in drones and camera sensors allow for testing current inversion techniques...
Article
Mediterranean countries are known worldwide for their significant contribution to olive oil production, which generates large amounts of olive mill wastewater (OMW) that degrades land and water environments near the disposal sites. OMW consists of organic substances with high concentrations of phenolic compounds along with inorganic particles. The...
Preprint
Shallow bathymetry inversion algorithms have long been applied in various types of remote sensing imagery with relative success. However, this approach requires that imagery with increased radiometric resolution in the visible spectrum is available. The recent developments in drones and camera sensors allow for testing current inversion techniques...
Article
Full-text available
Soil erosion is a constant environmental threat for the entirety of Europe. Numerous studies have been published during the last years concerning assessing soil erosion utilising Remote Sensing (RS) and Geographic Information Systems (GIS). Such studies commonly employ empirical erosion models to estimate soil loss on various spatial scales. In thi...
Article
Monitoring sedimentary bedforms is crucial for coastal planning projects. Detailed shallow bathymetry is a fundamental tool for analyzing sedimentary bedforms, however it is often unavailable due to fieldwork limitations. This study utilizes high resolution satellite-derived bathymetry (SDB) for monitoring nearshore bedforms at the northern coast o...
Article
Full-text available
Over the last few years, landslides have occurred more and more frequently worldwide, causing severe effects on both natural and human environments. Given that landslide susceptibility (LS) assessments and mapping can spatially determine the potential for landslides in a region, it constitutes a basic step in effective risk management and disaster...
Presentation
Full-text available
Integrating spectral and multi view features from drone based imagery for effective shallow bathymetry retrieval
Article
Full-text available
The risk of erosion is particularly high in Mediterranean areas, especially in areas that are subject to a not so effective agricultural management–or with some omissions–, land abandonment or wildfires. Soils on Crete are under imminent threat of desertification, characterized by loss of vegetation, water erosion, and subsequently, loss of soil. S...
Article
Full-text available
Among the environmental threats, the intensification of natural hazards, such as soil erosion may threaten the integrity and value of cultural heritage sites. In this framework, the present study’s main objective was to identify archaeological sites susceptible by soil erosion, taking the case study of Chania prefecture in Crete Island. Remotely se...
Article
Full-text available
Soil erosion is a severe and continuous environmental problem caused mainly by natural factors, which can be enhanced by anthropogenic activities. The morphological relief with relatively steep slopes, the dense drainage network, and the Mediterranean climate are some of the factors that render the Paleochora region (South Chania, Crete, Greece) pa...
Poster
Full-text available
Cultural heritage monuments and sites, as an integral part of the human-built environment, are completely exposed to natural hazards' adverse actions. Hence, the identification of the sites being exposed to soil erosion can be considered as a crucial need. In this framework, this study's main objective was to identify archaeological sites susceptib...
Poster
Full-text available
The present study has as main objectives: (a) to estimate the soil loss rate by water-induced erosion for the Crete Island between January and December 2020 as a result of RUSLE modeling, and (b) to explore the impact of intra-annual variabilities of rainfall erosivity (R) and cover management (C) factors and their temporal interactions on estimate...
Article
Full-text available
The European Space Agency (ESA), through the Climate Change Initiative (CCI), is currently providing nearly 4 decades of global satellite‐observed, fully homogenized soil moisture data for the uppermost 2‐5 cm of the soil layer. This data is valuable as it comprises one of the most complete remotely sensed soil moisture datasets available in time a...
Article
Research efforts related to better understanding and capture of the fertility trends over the time are considered to be of significant interest in the fields of demography and social sciences. In Greece, the overall relationships between fertility and numerous determinants that influence it have been explored at national level. However, the possibl...
Technical Report
Full-text available
Η έντονη βροχόπτωση που έπληξε τον νησιωτικό χώρο της Κρήτης το διήμερο 9-10 Νοεμβρίου 2020 είχε ως αποτέλεσμα την εκδήλωση εκτεταμένων πλημμυρικών και κατολισθητικών φαινομένων σε οικιστικές και αγροτικές περιοχές του νησιού. Μεταξύ των σοβαρά πληγεισών περιοχών ήταν η Περιφερειακή Ενότητα Ρεθύμνης, με τις επιπτώσεις της κακοκαιρίας τόσο στις υποδ...
Article
Full-text available
We present and assess a method to estimate missing values in daily precipitation time series for the Mediterranean island of Crete. The method involves a quantile mapping methodology originally developed for the bias correction of climate models’ output. The overall methodology is based on a two-step procedure: (a) assessment of missing values from...
Article
Full-text available
Under the continuously changing conditions of the environment, the exploration of spatial variability of soil erosion at a sub-annual temporal resolution, as well as the identification of high-soil loss time periods and areas, are crucial for implementing mitigation and land management interventions. The main objective of this study was to estimate...
Data
Message from the Guest Editors Dear Colleagues, The aim of this Special Issue is to collect original manuscripts on innovative research using state-of-the-art remote sensing sciences and technologies to assess the impact of soil salinity (or salinization) in different environments (semi-arid, arid, etc.) on agricultural land, land degradation, ve...
Cover Page
Full-text available
Multi-temporal Land use and Land cover (LULC) monitoring is a crucial parameter for assessing an area’s landscape ecology regime. LULC changes can be effectively used to describe dynamics of both urban or rural environments and vegetation patterns as an important indicator of ecological environments. In this context, spatial land use properties can...
Article
Full-text available
Interactions between soil and rainfall plays a vital role in ecological, hydrological and biogeochemical cycles of land. Among those interactions, the phenomenon of rainfall induced soil erosion is crucial to the soil functions, as it affects the soil structure and organic matter content that subsequently affects soil ability to hold moisture and n...
Poster
Full-text available
Land cover describes the general biophysical state of the surface providing also information about other aspects of the land, such as soils and water. Changes in land cover may have noticeable impact on the ecosystem biodiversity, water resources, climate system and socio-economic sectors. Therefore, the need for detecting these changes is more and...
Poster
Full-text available
Cornerstone of the meteorological and climatological science is the quality measurements of the precipitation. Large instrumentation gaps occur due to network destructions (fires, wars) or even technical limitations that dictate network reorganizations. This is a difficult to tackle issue as there are legacy networks that provide decades of valuabl...
Poster
Full-text available
The regular patterns of soil erosion tend to change at different scales of observation, affecting the mechanism of soil erosion and its evolution characteristics. Fragmentation and land loss are two critical, interrelated processes that influence the entire landscape. In this study, we examine how the relationship between landscape fragmentation an...
Article
Soil erosion constitutes an increasing thread for soil productivity and food security. Projected changes in Eastern Mediterranean rainfall regime show less but more intense rainfall events that are expected to affect the soil erosion processes. Research on the field has shown that the accurate estimation of rainfall erosivity dependents on the temp...
Poster
Full-text available
This work constitutes part of the research project named with the acronym "5DARE". In general, "5DARE" aims to develop an advanced 5D (3D + time + scale) multipurpose system for integrating and managing various types of information concerning soil erosion in the island of Crete, Greece, with means of Earth Observation (EO). Modeling techniques will...
Article
Full-text available
The main objective of this study was to explore the impact of various spectral indices on the performance of change vector analysis (CVA) for detecting the land cover changes on the island of Crete, Greece, between the last two decades (1999-2009 and 2009-2019). A set of such indices, namely, normalized difference vegetation index (NDVI), soil adju...
Article
Full-text available
Earth observation sensors continually provide datasets with different spectral and spatial characteristics, while a series of pre- and postprocessing techniques are needed for calibration purposes. Nowadays, a variety of satellite images have become accessible to researchers, while big data cloud platforms allow them to deal with an extensive numbe...
Poster
Full-text available
Multi-temporal Land use/Land cover (LULC) monitoring is a crucial parameter for assessing an area’s landscape ecology regime. LULC changes can be effectively used to describe dynamics of both urban or rural environments and vegetation patterns as an important indicator of ecological environments. In this context, spatial land cover properties can b...
Article
Full-text available
Soil erosion is one of the main causes of soil degradation among others (salinization, compaction, reduction of organic matter, and non-point source pollution) and is a serious threat in the Mediterranean region. A number of soil properties, such as soil organic matter (SOM), soil structure, particle size, permeability, and Calcium Carbonate equiva...
Conference Paper
Full-text available
This study aims to research the potential of Earth Observation (EO) products, such as Synthetic Aperture Radar (SAR) (Sentinel-1), and Landsat 8, in estimating volumetric Soil Moisture Content (SMC) in support of hydrological modeling. Ground SMC data were collected during 2015 from a gauge station network established in Western, Crete, Greece. Sat...
Article
Differential Interferometric Synthetic Aperture Radar (DInSAR) methodology hasbeen successfully employed to detect water level changes and produce corresponding water level variation maps. In this study, Agia and Kournas lakes, located in Western Crete, Greece, were used as pilot areas to monitor water level change with means of SAR interferometry...
Article
Full-text available
In this study, an attempt was made to identify the tracks of the synoptic-scale cyclones associated with flood events in Crete, a Greek island in the southern Aegean Sea and to investigate their kinematic and dynamic characteristics and vertical structure for a period of 25 years. Furthermore, a comparison is made with the corresponding characteris...
Article
A methodology for elaborating multi-temporal Sentinel-1 and Landsat 8 satellite images for estimating topsoil Soil Moisture Content (SMC) to support hydrological simulation studies is proposed. After pre-processing the remote sensing data, backscattering coefficient, Normalized Difference Vegetation Index (NDVI), thermal infrared temperature and in...
Article
Full-text available
The study focuses on the creation of an innovative methodology for the development of a risk assessment model for the archaeological sites of western Cyprus (Paphos district). On site observation is the most common way for monitoring cultural heritage sites and monuments in Cyprus. However, this procedure which includes data collection, periodical...
Article
The development of high spatial resolution Digital Elevation Models takes place via the use of GeoEye-1 stereo-pair imagery, providing high accurate geometry representation of a complex riverine system. The combination of geographic information systems with hydraulic models facilitates the exploitation of the satellite extracted topographic informa...
Article
Salinisation is one of the major soil degradation threats occurring worldwide. This study evaluates the feasibility of operational surface soil salinity mapping based on state-of-the-art Earth Observation (EO) products captured by sensors on-board WorldView-2 (WV2) and Landsat 8 satellites. The proposed methods are tested in Timpaki, south-central...
Article
To date, archived aerial photographs or recently declassified satellite CORONA images have been used to support archaeological research. However the use of such images is limited to the interpretation of greyscale images, which can be improved by image analysis processes including filters, edge detection techniques, etc. This article presents a met...
Article
Full-text available
Precipitation plays a significant role to energy exchange and material circulation in Earth’s surface system. According to numerous studies, traditional point measurements based on rain gauge stations are unable to reflect the spatial variation of precipitation effectively. On the other hand, satellite remote sensing could solve this limitation by...
Article
Olive oil mill wastes (OOMW) constitute a major pollution factor in olive-growing regions and an important problem to be solved for the agricultural industry. Olive oil mill wastes are normally deposited in tanks, or directly into the soil or even on adjacent torrents, rivers, and lakes, posing a high risk of environmental pollution in regard to pu...
Article
Full-text available
This paper investigates the potential use of the high resolution FormoSAT-2 sensor for supporting archaeological research. Although satellite remote sensing data have been widely used in the context of archaeological research, the high-resolution FormoSAT-2 dataset has attracted little attention. For a better understanding of the Neolithic habitati...
Conference Paper
Full-text available
A number of methods have been proposed for the atmospheric correction of the multispectral satellite images, based on either atmosphere modelling or images themselves. Full radiative transfer models require a lot of ancillary information about the atmospheric conditions at the acquisition time. Whereas, image based methods cannot account for all th...
Poster
The development of high impact climate systems over the Eastern Mediterranean is often associated with extreme weather conditions that cause flood disasters. The proposed research will include the use of state of the art hydro-meteorological and remote sensing products towards an innovative and effective forecasting and mitigation of flood events o...
Article
Full-text available
Urbanisation processes as a result of population growth, migration and infrastructure initiatives have a direct impact to cultural heritage sites. This paper aims to monitor growth dynamics of the urbanisation process that took place in the Paphos district, southwest Cyprus during the last decades, and evaluate its impact to monuments and archaeolo...
Book
New geoinformatic technologies have recently had a transformative effect on landscape archaeology, particularly by facilitating the high resolution acquisition and analysis of data over large areas. These techniques have fundamentally changed the nature and scope of questions that can be addressed regarding the archaeological record. Despite this s...
Article
A linear 3-D transformation that can be used for the enhancement of crop marks related to buried archaeological features is developed and presented in this article. The methodology is based on three steps: (1) recalculation of the ground narrowband spectroradiometric measurements to the multispectral Landsat 5 Thematic Mapper (TM) sensor, based on...
Article
Full-text available
Water pipelines need to be systematically monitored in order to minimize losses from possible leakages. In this paper, remote sensing techniques have been exploited in semiarid areas of Cyprus. In addition, ground spectroradiometer has been used to define the leakage's threshold values. The data were analysed in a GIS environment. Two known leakage...
Conference Paper
Full-text available
The olive-oil industry is one of the most important sectors of agricultural production in Greece, which is the third in olive-oil production country worldwide. Olive oil mill wastes (OOMW) constitute a major factor in pollution in olive-growing regions and an important problem to be solved for the agricultural industry. The olive-oil mill wastes ar...