Modern technological advances have enriched the means for electronic representation of 3-D data. ... more Modern technological advances have enriched the means for electronic representation of 3-D data. Proper data acquisition enables the production of visualisations of the built environment as close to reality as possible. In this paper such an effort is described. The theoretical approach is followed by the description of a specific application concerning the representation of an old traditional settlement, which was destroyed by an earthquake. The data collection and the processing of the 3-D data are described in detail. Finally sample renderings are presented and compared to old amateur photographs available. The results are discussed and assessed for their representation value and usefulness. KURZFASSUNG Die modernen technologischen Fortschritte haben zweifellos die Mitteln fur die elektronische Representierung von 3-D Daten bereichert. Geeignete Datenerfassung erleichtet die Produktion von Visualisierungen der gebauten Umwelt so nah der Realitat wie moglich. In diesem Bericht wird ein solcher versuch beschreibt. Nach der theoretischen Einfuhrung folgt die Beschreibung der spezifischen Anwendung, die sich mit der Representierung von einer traditionellen Siedlung, die von einem Erdbeben zerstort wurde, beschaftigt. Die Datenerfassung und die Verarbeitung der 3-D Daten werden ausfuhrlich beschrieben. Die Ergebnisse werden ausgewertet fur ihre Representationswert und Benutzbarkeit.
Cartographers are simplifying lines by eliminating unneeded details or by exaggerating several ch... more Cartographers are simplifying lines by eliminating unneeded details or by exaggerating several characteristics when they are performing any generalisation task on the basis of their experience and knowledge. The results of manual simplification should preserve the shape or the ...
ISPRS international journal of geo-information, Jun 22, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Euro-Mediterranean Journal for Environmental Integration
A strategic instrument for the sustainable conservation of the fragile marine ecosystem is the de... more A strategic instrument for the sustainable conservation of the fragile marine ecosystem is the designation of Marine Protected Areas (MPAs), within which various regulations exist for the protection of highly vulnerable species and habitats. These regulations can be depicted on Electronic Navigational Charts (ENCs) based on the new International Hydrographic Organization (IHO) S-100 series of standards, which support Marine Information Overlays (MIOs) that enrich the portrayed information by including both static and dynamic information, such as vessels traffic, tides, currents, and weather conditions, as well as essential information for the regulation of MPAs. Although, the new IHO S-122 Product Specification introduced specifically for the MPAs has been developed to encapsulate geospatial information for these regulations, the present edition does not specify portrayal. This paper reviews the legal foundation for the protection of marine mammals as well as the mapping methods use...
Introduction Line generalization can be considered as one of the most complex processes in the ca... more Introduction Line generalization can be considered as one of the most complex processes in the cartographic production. In manual line generalization, cartographers ought to select the features to be maintained at the target scale and modify them properly in order to form a geographically accurate and visually effective product; they are taking into account factors such as the rate of scale change, the character of the cartographic line and the purpose of the map. A holistic procedure is followed by cartographers through which they examine the line both globally and locally, estimating how the retention, modification or removal of each line characteristic could affect its neighbor locations as well as the whole line. According to Brassel and Weibel (1988), line generalization is a mental process of information processing that contains functions like comparison, combination, discrimination, recognition of relations, removing etc. It is evident that manual line generalization is a subjective procedure, depending on logical and aesthetic criteria. In digital cartography, the aim is the automation of line generalization process. Research focuses on finding methods of formalizing the manual generalization techniques satisfying the constraints generalization depends on. Cartographic research concludes that the most valid way to achieve this goal is the development of universal line generalization systems which operate on the basic principle of line"s "segmentationanalysis-generalization by appropriate operator" (
Electronic navigational charts (ENCs) are specialised geospatial datasets, issued by or on the au... more Electronic navigational charts (ENCs) are specialised geospatial datasets, issued by or on the authority of a government or hydrographic office, in accordance with the International Hydrographic Organisation's (IHO) standards, specifications and symbol sets. The datasets generally comprise encoded information collected from hydrographic surveys, aimed primarily at the safety of navigation. Most ENCs are not openly available, since the encrypted datasets can be acquired through various license schemes via a centralised distribution network coordinated by two organisations operating on behalf of the coastal states that produce them. This paper describes a methodology and an integrated system developed at the National Technical University of Athens Cartography Laboratory for the generation of web-based nautical charts utilising open data and free software. The system compiles nautical charts compliant with IHO's S-101 latest standard; using open hydrospatial data retrieved from...
Cable laying applications require real time positioning related to information included in maps. ... more Cable laying applications require real time positioning related to information included in maps. Global Positioning System (GPS) technology provides the most reliable real time positioning and timing while a Geographic Information System (GIS) is the most appropriate environment for managing maps in digital form. Experience from projects already undertaken has shown that it is crucial to enrich the positioning information with spatial and dynamic data. Specifically, cable laying activities need position to be combined with information related to seafloor morphology, seabed geomorphology, coastline, etc. together with information such as sea current velocity, laid cable length, cable tension, etc. Based on the above approach, the design of a navigating and monitoring system for cable laying is introduced. The system is built on a GIS platform connected to the appropriate spatial database and is attached to GPS receiver and the necessary sensors.
This paper introduces smart marine ecosystem-based planning (SMEP), a marine spatial planning (MS... more This paper introduces smart marine ecosystem-based planning (SMEP), a marine spatial planning (MSP) strategy for more participatory and responsive marine governance by leveraging “smart” digital services. SMEP denotes an iterative MSP process with planning cycles that incorporate continuous data gathering of spatial–temporal natural phenomena and human activities in coastal and marine areas, with ongoing data mining to locate key patterns and trends, to strive for periodic refinement of the MSP output. SMEP aims to adopt an ecosystem-based approach, taking into account both living and nonliving aspects of the marine environment, and making use of all available spatial data at various resolutions. In pursuit of SMEP implementation, the paper examines the current state of the MSP process in Greece and relates its long-term success with the establishment of a marine spatial data infrastructure (MSDI), employing contemporary nautical cartography standards along with hydrospatial data se...
Eye tracking recordings could reveal the visual behavior for different cartographic visualization... more Eye tracking recordings could reveal the visual behavior for different cartographic visualization techniques, such as hill-shading, while at the same time eye tracking metrics (ETMs) can summarize the associated complexity levels in a concise and quantitative manner. In the present study, three different hill-shading methods, including: (i) the standard method based on ideal diffuse reflection, (ii) the Multidirectional Oblique- Weighted method – MDOW and (iii) the combination of a MDOW's variation with standard hill-shading, are evaluated and ranked in terms of their perceived visual complexity. The performed examination is based on both eye tracking techniques and expert judgement procedures. A weighted combination of basic ETMs has been used, implemented by the Landscape Rating Index – LRI. The weights resulted from an experts' judgement process where the opinions of experts in geoinformatics, cartography, geovisualization, experimental psychology, cognitive science, neur...
Η διπλωματική εργασία αποτελεί τμήμα ευρύτερης εμπειρικής έρευνας της από κοινού λειτουργίας των ... more Η διπλωματική εργασία αποτελεί τμήμα ευρύτερης εμπειρικής έρευνας της από κοινού λειτουργίας των δυναμικών μεταβλητών "διάρκεια" και "ρυθμός αλλαγής" και της επιρροής τους στην αποτελεσματικότητα της οπτικής αναζήτησης της κίνησης. Η κίνηση αποτελεί κυρίαρχο και αδιαμφισβήτητο χαρακτηριστικό που παρατηρείται σε στάδιο προ-προσοχής και καθοδηγεί την οπτική προσοχή. Ο προσδιορισμός του κατάλληλου εύρους των τιμών του ρυθμού αλλαγής, βασίστηκε στην κίνηση ενός σημειακού συμβόλου -αλλαγή σε τοποθεσία- σε οπτικές σκηνές λευκού υποβάθρου. Ως ρυθμός αλλαγής θεωρείται το πηλίκο της σταθερής, σε αριθμό, αλλαγής σε θέση του σημειακού συμβόλου στις οπτικές σκηνές, ως προς τη μεταβλητή διάρκεια προβολής τους. Η ερευνητική διαδικασία, πραγματοποιήθηκε μέσω ανάλυσης των οφθαλμικών κινήσεων και διεκπεραιώθηκε σε συνθήκες ελεύθερης παρατήρησης, χωρίς τα υποκείμενα να έχουν κάποια συγκεκριμένη εργασία να εκτελέσουν. Οι οφθαλμικές κινήσεις μεταφράζονται σε προσηλώσεις και η διερεύ...
Marine spatial “open” data infrastructures (MSDI) have a significant economic and societal potent... more Marine spatial “open” data infrastructures (MSDI) have a significant economic and societal potential for coastal nations and their realization is driven by the evolution of the International Hydrographic Organization’s (IHO) S-100 data model for facilitating marine domain interoperability and the World Wide Web Consortium’s (W3C) best practices for spatial data publishing on the Web. The recent European directive on open data and the re-use of public sector information, known as the “Open Data Directive” is a key driver towards the establishment of “open” MSDIs among other spatial data infrastructures. The paper discusses possible data architectures for the MSDIs, examines the maturity of open data platforms that they could be built upon and compares the most prominent marine spatial data models for their applicability in relation to three marine information domains. MSDIs can facilitate the continuous data capturing of spatial-temporal physical phenomena and human activities at sea...
Volunteered Geographic Information (VGI) is a widely used data source in various fields and servi... more Volunteered Geographic Information (VGI) is a widely used data source in various fields and services, such as environmental monitoring, disaster and crisis management, SDI, and mapping. Quality is a critical factor for the usability of VGI. This study focuses on evaluating logical consistency based on the topological relationships between geographic features while considering semantics. It addresses internal (i.e., between thematic layers) and external (i.e., between specific features from different thematic layers) logical consistency. Attribute completeness is computed to support the use of semantics. A tool for assessing the consistency and attribute completeness is designed and implemented in the ArcGIS environment. An open-source web mapping application informs users about VGI consistency with multiscale visualization and indices. Data from OpenStreetMap (OSM), one of the most popular collaborative projects, are evaluated for six European cities: Athens, Berlin, Paris, Utrecht,...
In the present paper the design and development of a software appropriate for introducing basic c... more In the present paper the design and development of a software appropriate for introducing basic cartographic principles to school children aged from nine to fourteen years old is analyzed and discussed. The selection of the concepts incorporated in the software design takes in consideration recent cartographic and psychological research trends. The design of the software is based mainly on four components: the existing cartographic principles (i.e. geometry, generalization, symbolization, map characteristics, etc.), children’s cognitive and educational level, the school curriculum, and contemporary trends for developing computer software. The prototype software is developed under an object-oriented environment, using Microsoft Visual Basic as programming language. It can be executed as an application under Microsoft Windows 95/98/NT v. 4/2000 operating environment on a typically configured PC with no special requirements. The graphical user interface (GUI) is simple, friendly and mo...
In this paper, the interaction of the basic elements of the didactic of geography and those of ca... more In this paper, the interaction of the basic elements of the didactic of geography and those of cartography, are examined and discussed and an implementation approach of introducing cartography in the elementary schools is proposed. Although the didactic of geography is an independent scientific topic, is based on the theory and the results of other sciences, such as geography which determines the content, general didactic, psychology and pedagogics which help to form the teaching methods on the one hand and evaluate the teaching process on the other. But, what is the role of map inside the body of such a complex mixture of scientific topics? This question could be answered theoretically by examining the relation between geography and cartography. Considering the didactic of cartography in isolation from the didactic of geography, three keywords: why, what, and how of school cartography are determined. A theoretical approach is developed for the determination of these keywords, and m...
This study examines possible ways first to restrain or even eliminate the “false” shades of the r... more This study examines possible ways first to restrain or even eliminate the “false” shades of the relief, created mainly by the direction of the natural sunlight presented on aerial-photo or satellite images, and then to replace them with the “correct” artificial hill-shading shades according to the cartographic principles of legibility and perceptibility, which allow the map user to easily and clearly interpret the relief’s shapes and formations. The natural shades are eliminated from the aerial-photo or satellite images by applying special radiometric and statistical processing in order to create images free of shades. An analytical description of the earth’s surface -stored as a digital elevation modelcombined with computing tools of a variety of hill-shading methods are used to produce a cartographic “correct” image of shades of the study area. Finally, image-processing techniques are applied to create new images composed by the “correct" shades and the shaded free aerial-pho...
The present paper presents the performance of an experimental cartographic study towards the exam... more The present paper presents the performance of an experimental cartographic study towards the examination of the minimum duration threshold required for the detection by the central vision of a moving point symbol on cartographic backgrounds. The examined threshold is investigated using backgrounds with discriminant levels of information. The experimental process is based on the collection (under free viewing conditions) and the analysis of eye movement recordings. The computation of fixation derived statistical metrics allows the calculation of the examined threshold as well as the study of the general visual reaction of map users. The critical duration threshold calculated within the present study corresponds to a time span around 400msec. The results of the analysis indicate meaningful evidences about these issues while the suggested approach can be applied towards the examination of perception thresholds related to changes occurred on dynamic stimuli.
Modern technological advances have enriched the means for electronic representation of 3-D data. ... more Modern technological advances have enriched the means for electronic representation of 3-D data. Proper data acquisition enables the production of visualisations of the built environment as close to reality as possible. In this paper such an effort is described. The theoretical approach is followed by the description of a specific application concerning the representation of an old traditional settlement, which was destroyed by an earthquake. The data collection and the processing of the 3-D data are described in detail. Finally sample renderings are presented and compared to old amateur photographs available. The results are discussed and assessed for their representation value and usefulness. KURZFASSUNG Die modernen technologischen Fortschritte haben zweifellos die Mitteln fur die elektronische Representierung von 3-D Daten bereichert. Geeignete Datenerfassung erleichtet die Produktion von Visualisierungen der gebauten Umwelt so nah der Realitat wie moglich. In diesem Bericht wird ein solcher versuch beschreibt. Nach der theoretischen Einfuhrung folgt die Beschreibung der spezifischen Anwendung, die sich mit der Representierung von einer traditionellen Siedlung, die von einem Erdbeben zerstort wurde, beschaftigt. Die Datenerfassung und die Verarbeitung der 3-D Daten werden ausfuhrlich beschrieben. Die Ergebnisse werden ausgewertet fur ihre Representationswert und Benutzbarkeit.
Cartographers are simplifying lines by eliminating unneeded details or by exaggerating several ch... more Cartographers are simplifying lines by eliminating unneeded details or by exaggerating several characteristics when they are performing any generalisation task on the basis of their experience and knowledge. The results of manual simplification should preserve the shape or the ...
ISPRS international journal of geo-information, Jun 22, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Euro-Mediterranean Journal for Environmental Integration
A strategic instrument for the sustainable conservation of the fragile marine ecosystem is the de... more A strategic instrument for the sustainable conservation of the fragile marine ecosystem is the designation of Marine Protected Areas (MPAs), within which various regulations exist for the protection of highly vulnerable species and habitats. These regulations can be depicted on Electronic Navigational Charts (ENCs) based on the new International Hydrographic Organization (IHO) S-100 series of standards, which support Marine Information Overlays (MIOs) that enrich the portrayed information by including both static and dynamic information, such as vessels traffic, tides, currents, and weather conditions, as well as essential information for the regulation of MPAs. Although, the new IHO S-122 Product Specification introduced specifically for the MPAs has been developed to encapsulate geospatial information for these regulations, the present edition does not specify portrayal. This paper reviews the legal foundation for the protection of marine mammals as well as the mapping methods use...
Introduction Line generalization can be considered as one of the most complex processes in the ca... more Introduction Line generalization can be considered as one of the most complex processes in the cartographic production. In manual line generalization, cartographers ought to select the features to be maintained at the target scale and modify them properly in order to form a geographically accurate and visually effective product; they are taking into account factors such as the rate of scale change, the character of the cartographic line and the purpose of the map. A holistic procedure is followed by cartographers through which they examine the line both globally and locally, estimating how the retention, modification or removal of each line characteristic could affect its neighbor locations as well as the whole line. According to Brassel and Weibel (1988), line generalization is a mental process of information processing that contains functions like comparison, combination, discrimination, recognition of relations, removing etc. It is evident that manual line generalization is a subjective procedure, depending on logical and aesthetic criteria. In digital cartography, the aim is the automation of line generalization process. Research focuses on finding methods of formalizing the manual generalization techniques satisfying the constraints generalization depends on. Cartographic research concludes that the most valid way to achieve this goal is the development of universal line generalization systems which operate on the basic principle of line"s "segmentationanalysis-generalization by appropriate operator" (
Electronic navigational charts (ENCs) are specialised geospatial datasets, issued by or on the au... more Electronic navigational charts (ENCs) are specialised geospatial datasets, issued by or on the authority of a government or hydrographic office, in accordance with the International Hydrographic Organisation's (IHO) standards, specifications and symbol sets. The datasets generally comprise encoded information collected from hydrographic surveys, aimed primarily at the safety of navigation. Most ENCs are not openly available, since the encrypted datasets can be acquired through various license schemes via a centralised distribution network coordinated by two organisations operating on behalf of the coastal states that produce them. This paper describes a methodology and an integrated system developed at the National Technical University of Athens Cartography Laboratory for the generation of web-based nautical charts utilising open data and free software. The system compiles nautical charts compliant with IHO's S-101 latest standard; using open hydrospatial data retrieved from...
Cable laying applications require real time positioning related to information included in maps. ... more Cable laying applications require real time positioning related to information included in maps. Global Positioning System (GPS) technology provides the most reliable real time positioning and timing while a Geographic Information System (GIS) is the most appropriate environment for managing maps in digital form. Experience from projects already undertaken has shown that it is crucial to enrich the positioning information with spatial and dynamic data. Specifically, cable laying activities need position to be combined with information related to seafloor morphology, seabed geomorphology, coastline, etc. together with information such as sea current velocity, laid cable length, cable tension, etc. Based on the above approach, the design of a navigating and monitoring system for cable laying is introduced. The system is built on a GIS platform connected to the appropriate spatial database and is attached to GPS receiver and the necessary sensors.
This paper introduces smart marine ecosystem-based planning (SMEP), a marine spatial planning (MS... more This paper introduces smart marine ecosystem-based planning (SMEP), a marine spatial planning (MSP) strategy for more participatory and responsive marine governance by leveraging “smart” digital services. SMEP denotes an iterative MSP process with planning cycles that incorporate continuous data gathering of spatial–temporal natural phenomena and human activities in coastal and marine areas, with ongoing data mining to locate key patterns and trends, to strive for periodic refinement of the MSP output. SMEP aims to adopt an ecosystem-based approach, taking into account both living and nonliving aspects of the marine environment, and making use of all available spatial data at various resolutions. In pursuit of SMEP implementation, the paper examines the current state of the MSP process in Greece and relates its long-term success with the establishment of a marine spatial data infrastructure (MSDI), employing contemporary nautical cartography standards along with hydrospatial data se...
Eye tracking recordings could reveal the visual behavior for different cartographic visualization... more Eye tracking recordings could reveal the visual behavior for different cartographic visualization techniques, such as hill-shading, while at the same time eye tracking metrics (ETMs) can summarize the associated complexity levels in a concise and quantitative manner. In the present study, three different hill-shading methods, including: (i) the standard method based on ideal diffuse reflection, (ii) the Multidirectional Oblique- Weighted method – MDOW and (iii) the combination of a MDOW's variation with standard hill-shading, are evaluated and ranked in terms of their perceived visual complexity. The performed examination is based on both eye tracking techniques and expert judgement procedures. A weighted combination of basic ETMs has been used, implemented by the Landscape Rating Index – LRI. The weights resulted from an experts' judgement process where the opinions of experts in geoinformatics, cartography, geovisualization, experimental psychology, cognitive science, neur...
Η διπλωματική εργασία αποτελεί τμήμα ευρύτερης εμπειρικής έρευνας της από κοινού λειτουργίας των ... more Η διπλωματική εργασία αποτελεί τμήμα ευρύτερης εμπειρικής έρευνας της από κοινού λειτουργίας των δυναμικών μεταβλητών "διάρκεια" και "ρυθμός αλλαγής" και της επιρροής τους στην αποτελεσματικότητα της οπτικής αναζήτησης της κίνησης. Η κίνηση αποτελεί κυρίαρχο και αδιαμφισβήτητο χαρακτηριστικό που παρατηρείται σε στάδιο προ-προσοχής και καθοδηγεί την οπτική προσοχή. Ο προσδιορισμός του κατάλληλου εύρους των τιμών του ρυθμού αλλαγής, βασίστηκε στην κίνηση ενός σημειακού συμβόλου -αλλαγή σε τοποθεσία- σε οπτικές σκηνές λευκού υποβάθρου. Ως ρυθμός αλλαγής θεωρείται το πηλίκο της σταθερής, σε αριθμό, αλλαγής σε θέση του σημειακού συμβόλου στις οπτικές σκηνές, ως προς τη μεταβλητή διάρκεια προβολής τους. Η ερευνητική διαδικασία, πραγματοποιήθηκε μέσω ανάλυσης των οφθαλμικών κινήσεων και διεκπεραιώθηκε σε συνθήκες ελεύθερης παρατήρησης, χωρίς τα υποκείμενα να έχουν κάποια συγκεκριμένη εργασία να εκτελέσουν. Οι οφθαλμικές κινήσεις μεταφράζονται σε προσηλώσεις και η διερεύ...
Marine spatial “open” data infrastructures (MSDI) have a significant economic and societal potent... more Marine spatial “open” data infrastructures (MSDI) have a significant economic and societal potential for coastal nations and their realization is driven by the evolution of the International Hydrographic Organization’s (IHO) S-100 data model for facilitating marine domain interoperability and the World Wide Web Consortium’s (W3C) best practices for spatial data publishing on the Web. The recent European directive on open data and the re-use of public sector information, known as the “Open Data Directive” is a key driver towards the establishment of “open” MSDIs among other spatial data infrastructures. The paper discusses possible data architectures for the MSDIs, examines the maturity of open data platforms that they could be built upon and compares the most prominent marine spatial data models for their applicability in relation to three marine information domains. MSDIs can facilitate the continuous data capturing of spatial-temporal physical phenomena and human activities at sea...
Volunteered Geographic Information (VGI) is a widely used data source in various fields and servi... more Volunteered Geographic Information (VGI) is a widely used data source in various fields and services, such as environmental monitoring, disaster and crisis management, SDI, and mapping. Quality is a critical factor for the usability of VGI. This study focuses on evaluating logical consistency based on the topological relationships between geographic features while considering semantics. It addresses internal (i.e., between thematic layers) and external (i.e., between specific features from different thematic layers) logical consistency. Attribute completeness is computed to support the use of semantics. A tool for assessing the consistency and attribute completeness is designed and implemented in the ArcGIS environment. An open-source web mapping application informs users about VGI consistency with multiscale visualization and indices. Data from OpenStreetMap (OSM), one of the most popular collaborative projects, are evaluated for six European cities: Athens, Berlin, Paris, Utrecht,...
In the present paper the design and development of a software appropriate for introducing basic c... more In the present paper the design and development of a software appropriate for introducing basic cartographic principles to school children aged from nine to fourteen years old is analyzed and discussed. The selection of the concepts incorporated in the software design takes in consideration recent cartographic and psychological research trends. The design of the software is based mainly on four components: the existing cartographic principles (i.e. geometry, generalization, symbolization, map characteristics, etc.), children’s cognitive and educational level, the school curriculum, and contemporary trends for developing computer software. The prototype software is developed under an object-oriented environment, using Microsoft Visual Basic as programming language. It can be executed as an application under Microsoft Windows 95/98/NT v. 4/2000 operating environment on a typically configured PC with no special requirements. The graphical user interface (GUI) is simple, friendly and mo...
In this paper, the interaction of the basic elements of the didactic of geography and those of ca... more In this paper, the interaction of the basic elements of the didactic of geography and those of cartography, are examined and discussed and an implementation approach of introducing cartography in the elementary schools is proposed. Although the didactic of geography is an independent scientific topic, is based on the theory and the results of other sciences, such as geography which determines the content, general didactic, psychology and pedagogics which help to form the teaching methods on the one hand and evaluate the teaching process on the other. But, what is the role of map inside the body of such a complex mixture of scientific topics? This question could be answered theoretically by examining the relation between geography and cartography. Considering the didactic of cartography in isolation from the didactic of geography, three keywords: why, what, and how of school cartography are determined. A theoretical approach is developed for the determination of these keywords, and m...
This study examines possible ways first to restrain or even eliminate the “false” shades of the r... more This study examines possible ways first to restrain or even eliminate the “false” shades of the relief, created mainly by the direction of the natural sunlight presented on aerial-photo or satellite images, and then to replace them with the “correct” artificial hill-shading shades according to the cartographic principles of legibility and perceptibility, which allow the map user to easily and clearly interpret the relief’s shapes and formations. The natural shades are eliminated from the aerial-photo or satellite images by applying special radiometric and statistical processing in order to create images free of shades. An analytical description of the earth’s surface -stored as a digital elevation modelcombined with computing tools of a variety of hill-shading methods are used to produce a cartographic “correct” image of shades of the study area. Finally, image-processing techniques are applied to create new images composed by the “correct" shades and the shaded free aerial-pho...
The present paper presents the performance of an experimental cartographic study towards the exam... more The present paper presents the performance of an experimental cartographic study towards the examination of the minimum duration threshold required for the detection by the central vision of a moving point symbol on cartographic backgrounds. The examined threshold is investigated using backgrounds with discriminant levels of information. The experimental process is based on the collection (under free viewing conditions) and the analysis of eye movement recordings. The computation of fixation derived statistical metrics allows the calculation of the examined threshold as well as the study of the general visual reaction of map users. The critical duration threshold calculated within the present study corresponds to a time span around 400msec. The results of the analysis indicate meaningful evidences about these issues while the suggested approach can be applied towards the examination of perception thresholds related to changes occurred on dynamic stimuli.
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