MARIA TASSOPOULOU | Aristotle University of Thessaloniki (original) (raw)

Papers by MARIA TASSOPOULOU

The concept of Essential Variables (EVs) has emerged within the remote sensing community in recen... more The concept of Essential Variables (EVs) has emerged within the remote sensing community in recent years. The EVs, having previously defined as a minimal set of variables that determines the system's state and development, have attracted considerable interest not only for remote sensing scientists, but from several, diverse thematic groups and communities. The driving forces behind this evolution, relates primary to the need to support national to global monitoring, reporting, research, and forecasting of complex earth systems, to the necessity for an essential set of parameters that could be used for monitoring progress towards the goals of different thematic communities as well as to the requirement to support consistent, objective temporal information provision for policy development and implementation. Also, considering the availability of sensor data with similar characteristics from different satellites orbiting around earth, there is a need to standardize the information extracted, independently of the observational platform and the processing algorithms as well as to provide this information in a more streamlined, comprehensible form to end-users not well acquainted with the remote sensing technology and terminology. So far, EVs have been introduced and adopted for monitoring oceans, climate and biodiversity systems as well as measuring progress towards UN Sustainable Development Goals (SDGs) implementation, while several other communities are in the process of adopting this concept in their domain. This study will review the recent progress as well as the current challenges and future developments in the research agenda around EVs. In particular we review the current state of EVs and their connection to the different scientific communities, as well as cross-domain interactions and synergies. We then describe potential new thematic areas and scientific communities where the concept of EVs could be applied and provide the outline of the process to be followed for identifying these variables.

Seventh International Conference on Remote Sensing and Geoinformation of Environment, 2019

The international community has recently agreed on the need to address global challenges related ... more The international community has recently agreed on the need to address global challenges related to environmental degradation, climate change, poverty, inequality, prosperity, and peace and justice. The United Nations Agenda 2030 sets 17 Sustainable Development Goals (SDGs) that are monitored through 169 societal targets and 232 Indicators that should be accomplished till 2030, in order to ensure sustainability of the systems and the resources for the future generations. Monitoring of this progress can be implemented through the concept of the Essential Variables (EVs) defined as the minimum set of variables required to characterize a change of a system. Remote Sensing, providing multi-scale, multispectral and multi-temporal wide coverage of earth's surface, can facilitate the monitoring of EVs trends over space and time. While global initiatives and research projects are currently work on streamlining the use of remote sensing data to the SDGs and EVs monitoring process, challenges exist on the identification and the selection of the proper variables and Indicators as well as on the efficient processing of large data volumes delivering robust and comprehensible information to policy makers and managers. This study serves as a pilot for the use of EVs quantifying changes in two Indicators of SDGs over terrestrial (SDG 15) and marine ecosystems (SDG 6). Two different Mediterranean sites are selected, and a process based on multi-temporal datasets of freely available satellite imagery is used in order to identify the trends for the selected Indicators.

Lighthouses comprise a unique example of world cultural heritage, closely connected both with the... more Lighthouses comprise a unique example of world cultural heritage, closely connected both with the evolution of navigation techniques, as well as with the social and economic development of their surrounding areas. The way the lighthouse network has been organized in nodal sites along the coastlines, highlights the uniqueness of these structures as important landmarks with defined an unalterable position, regardless of the changes that may have occurred in the wider area.
The purpose of this study is to develop a methodology for identifying and controlling distortions in historical maps, using the position of lighthouses as check points. Specifically, in order to satisfy the objectives of this study, all existing information on the location and other relevant data pertaining to the structure of the lighthouses (height, luminous or nominal range, etc.) are organized in a geodatabase using Geographical Information System (GIS) tools. Moreover, historical maps for the areas of interest collected from various sources are georeferenced properly in order to be used in this analysis. The available information is visualized into individual spatial levels concerning both wider areas (e.g. National Lighthouse Network) and more specific areas (e.g. Lighthouse network in a specific region). The GIS user will be able to create spatial queries to compare the area around a lighthouse (coastline and terrain model) depicted in a new cartographic background with the corresponding area in a historical map. The results can be visualized in thematic maps and information about the terrain model (contour lines) and coastline changes can be provided. In order to evaluate these results, a statistical significance analysis is also performed. Finally, another objective of the study is the checking of the functionality of the lighthouses in older times. This objective is examined combing historical maps, a Digital Terrain Model (DTM) of the study area and relevant information about the structure of the lighthouses (e.g. height of the light, luminous range, nominal ranges etc.).

For centuries, many Christians, Jews and Muslims prayed and exercised their religious beliefs and... more For centuries, many Christians, Jews and Muslims prayed and exercised their religious beliefs and practices in sanctuaries belonging to another religion. The presence of “shared sacred sites” is a well-established phenomenon in the Mediterranean, revealing the permeability of the frontiers between various religious communities. Thessaloniki (Greece) is a prominent example of a historic city to narrate the story of these “shared sacred sites”, as the three monotheistic religions have traditionally flourished within its walls. The documentation of these sacred sites starts at the beginning of the 20th century. Terrestrial and aerial photographs, urban planning maps, sketches, drawings, post-cards and gravures are important forms and means of recording through time of these noteworthy landmarks that are still present or have been destroyed completely or in some cases partially. In reality, all of the above consist of the essential technical data and tools in order to study, analyze and visualize the ever-changing religious landscape of the city. In this context, this project is meant, among other things, to complete a thorough research on the evolution of Thessaloniki’s “shared sacred sites” using the tools and the know-how that are now at our disposal and create the necessary geographic background for a detailed and accurate documentation of its cultural and religious identity, highlighting at the same time the historical value and cultural significance of these places to the public.

In this paper, the photogrammetric procedure and the development of a G.I.S. application for the ... more In this paper, the photogrammetric procedure and the development of a G.I.S. application for the digital documentation of the Macedonian Palace in the archaeological site of Vergina-Aegeae in northern Greece are described. Within this framework, the focus is targeted towards the use of UAV (unmanned aerial vehicle) for the production of high resolution orthoimages, essential for the interpretation, detection and measurement of archeological features. The advantages of model helicopters are seen in their ability to operate close to the object, to be flexible in navigation and in viewing directions. For the acquisition of the aerial images in the area of the 4 th B.C. Palace in Vergina-Aegeae, a flight planning prior to fieldwork and a careful acquisition of the images was required to ensure successful postprocessing. The images were downloaded and processed already in the field in order to ensure good image quality, sufficient overlap between them and avoid large scale differences as well. The photogrammetric image processing of the data, comprising of the tie point measurement, bundle adjustment, DSM and orthophoto generation was done with the commercial software package LPS (Leica Photogrammetry Suite, Leica Geosystems), which offers functionalities for a complete photogrammetric working process. The resulting accuracy was acceptable for the 1:100 mapping. In addition to the above, within the general framework of the project, the development of a G.I.S. application with the commercial software package ArcGIS is described.

Within the framework of excavations at Keros Island in the Cyclades, the focus of this study is t... more Within the framework of excavations at Keros Island in the Cyclades, the focus of this study is targeted mainly towards the use of UAV (unmanned aerial vehicle) for the production of high resolution orthoimages, essential for the interpretation, detection and measurement of archaeological features and the use of laser scanner for the 3D documentation of archaeological trenches, dtm collection of the whole archeological site, Kavos and Dhaskalio, and 3D modelling of Cycladic figurines. For the acquisition of the aerial images in the site of Kavos and Dhaskalio, a flight planning prior to fieldwork and a careful acquisition of the images was required to ensure successful post processing. The photogrammetric image processing of the data, comprising of the tie point measurement, bundle adjustment, dsm and orthophoto generation was completed and the resulting accuracy was acceptable for the 1:500 mapping. A flythrough video was created also using the produced orthophotos and a Quick Bird Image in order to place the archeological site among a wider context. For the DTM collection and the modelling of the archaeological trenches an Optech ILRIS-3D laser scanner was used. The trenches were scanned with a 1cm resolution, while the DTM was scanned with a 20 cm resolution. Multiple scans of the objects were realized and they finally merged to produce were photorealistic three-dimensional triangle models. For the figurines modelling a next engine portable scanner was used. The figurines were scanned from multiple angles in order to cover every detail of their surface and were merged to produce high resolution photorealistic 3D models.

Geographic Information Systems (GIS) create the basis for dynamic, integrated data management lea... more Geographic Information Systems (GIS) create the basis for dynamic, integrated data management leading to the creation of a modern recording of our cultural heritage. This feature of GIS is the main tool for the documentation and preservation of our cultural wealth. In this project, we represent an attempt to build on the fundamental characteristics of GIS, which is the connection between spatial and descriptive data into a single reference system in order to create a standard model registration of traditional rural settlements of Greece. Furthermore, we examine different ways in order to use this model in the future to build a web application that will be able to be used by both specialist and non-specialists users as a travel guide of the settlements.
As an example of this application, we selected and present the traditional rural settlement of Asfontylitis in Amorgos Island. The settlement of Asfontylitis, is a small rural village in Oxo Meria of Amorgos, which is concerned as a rare and unique example of the traditional Cycladic Architecture. The settlement is also known since pre-historic years as one of the most important historical places of the Island.
The data collected using classic topographic methods and architectural analysis with in situ documentation and mapping of the whole area, are recorded and organized in a Geographical Information System (GIS), using as spatial background the topographic mapping of the settlement. After this first “in situ” documentation, the Geographical Information System, is organized and enhanced in different forms and ways that are presented in this project, so as to create a standard recording registry of this rural settlement.

Conference Presentations by MARIA TASSOPOULOU

ΛΕΞΕΙΣ ΚΛΕΙΔΙΑ: πυκνοδομημένος αστικός ιστός, Τεκμηρίωση, πολεοδομικός έλεγχος κτιρίου, Ιστορικό ... more ΛΕΞΕΙΣ ΚΛΕΙΔΙΑ: πυκνοδομημένος αστικός ιστός, Τεκμηρίωση, πολεοδομικός έλεγχος κτιρίου, Ιστορικό κέντρο Θεσσαλονίκης ΠΕΡΙΛΗΨΗ: Οι σύγχρονες τοπογραφικές, αρχιτεκτονικές και φωτογραμμετρικές μέθοδοι αποτύπωσης αποτελούν τα πλέον διαδεδομένα και χρησιμοποιούμενα εργαλεία για την καταγραφή και διάσωση του πολιτιστικού μας πλούτου. Η εφαρμογή των εν λόγω μεθόδων είναι μία πολύπλοκη διαδικασία όταν πρόκειται για νεότερα μνημεία που βρίσκονται σε πυκνοδομημένο αστικό ιστό και φιλοξενούν σύγχρονες χρήσεις. Τυπικό παράδειγμα αποτελεί το διατηρητέο κτίριο επί της οδού Αριστοτέλους 8 στο ιστορικό κέντρο της Θεσσαλονίκης που είναι ευρύτερα γνωστό ως «Βοσπόριον Μέγαρον». Το κτίριο ανεγέρθη την περίοδο 1921-1922 σε σχέδια του αρχιτέκτονα Ζακ Μωσσέ που σχεδίασε και το επιβλητικό κτίριο του κινηματογράφου Ολύμπιον στην πλατεία Αριστοτέλους. Το 1983 χαρακτηρίστηκε διατηρητέο στο σύνολό του με σχετική απόφαση του τότε ΥΠΕΧΩΔΕ (νυν εποπτείας ΥΜΑΘ) και σήμερα βρίσκεται στην κυριότητα ιδιωτών αποτελώντας ένα κτίριο – ορόσημο για την πόλη της Θεσσαλονίκης, φιλοξενώντας πλήθος εμπορικών και επαγγελματικών χρήσεων. Το οικόπεδο που αναπτύσσεται το κτίσμα είναι μία πλήρως διαμορφωμένη έκταση με πρόσωπο στον ιστορικό άξονα της Αριστοτέλους και περιβάλλεται από όμορα διατηρητέα κτίρια, αλλά και σύγχρονες κατασκευές. Η εργασία παρουσιάζει τα αναλυτικά βήματα για την τεκμηρίωση του μνημείου τόσο ως προς την αποτύπωσή του, όσο και ως προς την εν γένει διαχείρισή του με σκοπό την σύνταξη ενός πλήρους αρχείου καταγραφής του μνημείου (νομικός και πολεοδομικός έλεγχος, καταγραφή οικοδομικών φάσεων κλπ). Παράλληλα, τίθεται μία προβληματική όσον αφορά τη διαχείριση αντίστοιχων νεότερων μνημείων που παρουσιάζουν σημαντικές τεχνικές δυσκολίες τεκμηρίωσης εξαιτίας της θέσης τους σε ένα πυκνοδομημένο αστικό περιβάλλον. Τέλος, καταγράφονται όλες οι απαιτούμενες διεργασίες με τους αρμόδιους φορείς που είναι υπεύθυνοι για την προστασία του μνημείου.

Seventh International Conference on Remote Sensing and Geoinformation of Environment, 2019