The major goal of this exploratory project “Drone Zone Austria” is to design a web portal prototy... more The major goal of this exploratory project “Drone Zone Austria” is to design a web portal prototype as innovative contribution to air traffic management in order to support safe Remotely Piloted Aircraft Systems (RPAS, also known as unmanned aerial systems (UAS) or “drones”) mission planning. The web portal will provide a map-based representation of the legally defined 4 areas of operation for professional and recreational drone missions in Austria (Fig. 1). Furthermore, it will include a flight plan safety check incorporating documentation functionality based on the requirements defined in the legal operation approval.
The topic of geoprivacy is increasingly relevant as larger quantities of personal location data a... more The topic of geoprivacy is increasingly relevant as larger quantities of personal location data are collected and shared. The results of scientific inquiries are often spatially suppressed to protect confidentiality, limiting possible benefits of public distribution. Obfuscation techniques for point data hold the potential to enable the public release of more accurate location data without compromising personal identities. This paper examines the application of four spatial obfuscation methods for household survey data. Household privacy is evaluated by a nearest neighbor analysis, and spatial distribution is measured by a cross-k function and cluster analysis. A new obfuscation technique, Voronoi masking, is demonstrated to be distinctively equipped to balance between protecting both household privacy and spatial distribution.
Simulation of reality in computer games has recently been adopted for urban planning purposes. Mi... more Simulation of reality in computer games has recently been adopted for urban planning purposes. Minecraft™ is a computer game in which players use 1m³ blocks of various materials to construct buildings in an imaginary world. It has become popular recently as a geodesign tool for encouraging public participation in urban planning. As part of this research, a prototype model was developed based on the enhanced transformation of actual spatial datasets into a Minecraft virtual world. A Minecraft-based, collaborative geodesign participatory process was conducted in order to assess a geodesign proposal for a location within the study area in Austria. The research aims to explore the usability of Minecraft as a geodesign tool that can facilitate public participation in urban planning decision support. The results showed that maintaining adequate realism in Minecraft model designs can positively influence users' sense of orientation and improve their navigation in a Minecraft world. A disadvantage of using Minecraft is that assessing the reliability of designs for urban planning is time-consuming. Furthermore, using Minecraft models requires participants to be highly motivated
The rising number of UAS operations in the European airspace poses a safety issue. The key proble... more The rising number of UAS operations in the European airspace poses a safety issue. The key problem is to ensure safe drone traffic management and their integration into the existing air traffic environment. Thus, risk assessment becomes an integral part of every UAS operation and its automation is of great importance when dealing with growing numbers of flights. There exist many attempts to support such risk assessment, but an optimal solution is yet to be found. This paper presents a prototype of a web application, which automates strategic risk assessment of open and specific UAS operations in Austria with the use of open government geodata. Risk assessment results are visualized on a map, showing spatial distribution of classified risks in the operational area. This prototype is the first attempt to combine the functions of a "drone map" representing relevant geodata and a questionnaire usually used to support specific operation risk assessment. There is a potential to turn it into a tool which is used to create a comprehensive preflight safety portfolio or to support the automatic risk assessment performed by a UTM before a UAS operation is checked in. Simplifying the creation of safety portfolios and automating UAS operation risk assessment are important factors in promoting a wider and safer use of UAS.
Accessing geospatial data via the internet is a common way for data integration. This web mapping... more Accessing geospatial data via the internet is a common way for data integration. This web mapping approach often relies on web services like the web map tile service (WMTS) for accessing maps or the web feature service (WFS) for accessing vector data. An alternative way, which combines aspects like the higher performance through tiling and the usage of vector data is the usage of tiled vector data. This short paper describes an approach for the creation of tiled vector data using standard PostgreSQL, with spatial extension PostGIS, functionality. For that, custom PostGIS functions are implemented to select relevant vector data out of the PostgreSQL database, dynamically generalize/simplify geometries and transform the data to Mapbox mvt format. This approach of creating tiled vector data shall be used for further implementations of web maps for building more efficient spatial data infrastructures.
Remotely Piloted Aircraft Systems (RPAS) stellen aktuell ein rasant wachsendes technologisches Ma... more Remotely Piloted Aircraft Systems (RPAS) stellen aktuell ein rasant wachsendes technologisches Marktsegment dar, das speziell im Bereich der hochauflösenden Datenerfassung und des Monitorings enormes Potenzial für zivile Anwendungsmöglichkeiten im Geoinformationsbereich bietet. ZALOGA et al. (2013) schätzen, dass sich der weltweite RPAS Markt in Bezug auf jährliche Investitionsvolumina in neue Beschaffungen und F&E bis 2020 von derzeit (Stand 2013) ca. 5.2 Mrd. US$ auf 11.6 Mrd. US$ verdoppeln wird. In den USA werden durch eine gesetzlich geregelte Integration von RPAS in den zivilen Luftraum ab 2015 in den ersten 3 Jahren mehr als 70,000, und bis 2025 geschätzte 100,000 neue Jobs prognostiziert (AUVSI 2013). Mit der anstehenden nationalen und internationalen Eliminierung von bestehenden Barrieren für den zivilen RPAS-Einsatz werden neue Märkte für unbemannte luftfahrtsystembasierte Dienstleistungen erschlossen. Ausgelöst vom gesetzlich verabschiedeten Vorhaben der USA, zivile RPAS beginnend mit 2015 für Missionen im nationalen Luftraum zuzulassen, hat die Europäische Kommission 2013 eine europaweite Strategie für die Integration von zivilen RPAS Systemen in den europäischen Luftraum verabschiedet (EC-RPAS Roadmap 2013). Ein zentrales Element dieser Strategie ist die notwendige Erweiterung und Anpassung der gesetzlichen Rahmenbedingungen für die sichere Luftraumintegration sowohl auf europäischer als auch nationaler Ebene. Die jeweilige Zuständigkeit richtet sich dabei nach der RPAS-Gewichtsklasse, wobei für RPAS Systeme mit einem Gesamtgewicht größer als 150 kg die europäische Luftfahrtbehörde EASA zuständig ist, für Systeme mit einem Gesamtgewicht kleiner 150kg die jeweilige nationale Luftfahrtbehörde. Vor diesem Hintergrund wurde 2013 eine Novelle zum nationalen Luftfahrtgesetz in Österreich verabschiedet (LFG 2013), und die Austro Control mit der Erarbeitung der spezifischen Durchführungsbestimmungen beauftragt. Diese wurden im Dezember 2013 zur Begutachtung ausgesendet und traten mit 1.1.2014 gesetzlich in Kraft (ACG 2014). In diesen Durchführungsbestimmungen (Lufttüchtigkeits-und Betriebstüchtigkeitshinweis Nr. 67-LTBH 67) ist die Erteilung für Flugbewilligungen für die gewerbliche Nutzung und den Betrieb von unbemannten Luftfahrzeugen (uLFZ) geregelt. Die behördlichen Entscheidungskriterien für die Strenge der Auflagen sowie den Umfang des Bewilligungsprozesses ist eine Kombination aus Betriebsmasse (< 5 kg < 25 kg < 150 kg), Besiedlungsdichte des geplanten Einsatzgebietes (es werden die 4 Klassen unbebaut, unbesiedelt, besiedelt und dicht besiedelt unterschieden), sowie ob während der Mission ein Sichtkontakt mit einer maximale erlaubten Flughöhe von 150m zwischen RPAS und Pilot besteht (Klasse 1) oder nicht (Klasse 2). Abbildung 1 zeigt die daraus resultierende für Österreich gültige Kategorisierung von uLFZ.
Hochauflösende Oberflächenmodelle spielen heute eine große Rolle bei vielen Anwendungen im Bereic... more Hochauflösende Oberflächenmodelle spielen heute eine große Rolle bei vielen Anwendungen im Bereich der Hochwassersimulation, der Gefahrenzonenmodellierung, der Forstwirtschaft oder der Habitatsmodellierung, um nur einige Beispiele zu nennen. Aktuell werden diese Digitalen Oberflächenmodelle (DOM) vorwiegend durch Airborne Laser Scanning (ALS) erfasst und stellen mittlerweile einen immer weiter verbreitenden und flächendeckend verfügbaren Geobasisdatensatz nicht nur in Österreich dar. Speziell eine flächendeckende Erfassung und Nachführung von ALS-Daten ist zeitaufwendig und kostenintensiv, und kommt daher für die quantitative Analyse von raumzeitlichen Veränderungsprozessen nur bedingt infrage.
Riparian forests are critical for carbon storage, biodiversity, and river water quality. There ha... more Riparian forests are critical for carbon storage, biodiversity, and river water quality. There has been an increasing use of very-high-spatial-resolution (VHR) unmanned aircraft systems (UAS)-based remote sensing for riparian forest mapping. However, for improved riparian forest/zone monitoring, restoration, and management, an enhanced understanding of the accuracy of different classification methods for mapping riparian forests and other land covers at high thematic resolution is necessary. Research that compares classification efficacies of endmember- and object-based methods applied to VHR (e.g., UAS) images is limited. Using the Sequential Maximum Angle Convex Cone (SMACC) endmember extraction algorithm (EEA) jointly with the Spectral Angle Mapper (SAM) classifier, and a separate multiresolution segmentation/object-based classification method, we map riparian forests/land covers and compare the classification accuracies accrued via the application of these two approaches to narr...
Waterfowl monitoring is an important task for understanding waterfowl distribution and habitats. ... more Waterfowl monitoring is an important task for understanding waterfowl distribution and habitats. Surveying approaches using hyper-spatial airborne imagery, collected by small unoccupied aerial systems (sUAS), hold potential to overcome the limitations of traditional methods while improving count efficiency and reliability. Difficulties obtaining waterfowl counts, particularly in complex image scenes, from the high quantity of imagery required hinders deployment of large-scale surveys. In this paper, we test Convolutional Neural Networks (CNNs) to understand their potential and how they behave across different versions of our waterfowl dataset. Three CNN architectures (YOLO, Retinanet and Faster R-CNN) were trained on 3 hierarchical levels: waterfowl detection (True / False), waterfowl type (3 classes), and waterfowl species (8 classes). The architectures generally performed well, and results indicate that automated waterfowl detection in complex environments, and therefore enumeration, is feasible using current technology. Waterfowl identification in complex environments was not successful using the available training data, but we propose steps that might enhance the results.
ISPRS International Journal of Geo-Information, 2021
Global sensitivity analysis, like variance-based methods for massive raster datasets, is especial... more Global sensitivity analysis, like variance-based methods for massive raster datasets, is especially computationally costly and memory-intensive, limiting its applicability for commodity cluster computing. The computational effort depends mainly on the number of model runs, the spatial, spectral, and temporal resolutions, the number of criterion maps, and the model complexity. The current Spatially-Explicit Uncertainty and Sensitivity Analysis (SEUSA) approach employs a cluster-based parallel and distributed Python–Dask solution for large-scale spatial problems, which validates and quantifies the robustness of spatial model solutions. This paper presents the design of a framework to perform SEUSA as a Service in a cloud-based environment scalable to very large raster datasets and applicable to various domains, such as landscape assessment, site selection, risk assessment, and land-use management. It incorporates an automated Kubernetes service for container virtualization, comprising...
Flow patterns are an important indicator that helps fish to discover fish ladders. This feasibili... more Flow patterns are an important indicator that helps fish to discover fish ladders. This feasibility study investigates the possibility of a non-intrusive detection of surface flow patterns near a fish ladder in an Alpine river. The newly developed method concept involves the use of high-resolution drone based videos and the optical analysis method “Particle Image Velocimetry” (PIV). The flow patterns calculated with PIV are in good agreement with the hydraulic reference measurements, which were performed with the help of a propeller current meter. The results of this feasibility study can be seen as a first step towards the creation of an efficient and standardized methodology for flow analysis in the vicinity of fish ladders.
The use of UAS at professional as well as recreational level has been risen tremendously in the l... more The use of UAS at professional as well as recreational level has been risen tremendously in the last years. The FAA expects “around 7 million drones flying over America in 2020” (http://www.popsci.com/new-faareportstares-in-face-drone-filled-future ). Based on an estimation of the Austrian Aeroclub there have been about 17,000 drones sold only for recreational use in 2015 in a small country like Austria. This situation might cause an increased risk potential and high expected probability for incidences, especially for urban areas.
Gernot Paulus, Karl-Heinrich Anders, Melanie Regenfelder, Bernhard Kosar, Alexsandra Rieger, Klau... more Gernot Paulus, Karl-Heinrich Anders, Melanie Regenfelder, Bernhard Kosar, Alexsandra Rieger, Klaus Michor, Wolfgang Werth, Christoph Ungermanns, Hermann Sterner, Gerhard Hohenwarter, Christian Stefan, Rainer Gaggl, Heinz Stanek, Kurt Wagner, Markus Eisl, Anthony Fillipi, Inci Güneralp und André Skupin FH Kärnten – Geoinformation und Umwelttechnologien, Villach · [email protected] FH Kärnten – Systems Design, Villach REVITAL Integrative Naturraumplanung GmbH, Lienz ZAMG, Klagenfurt Technical Innovation – Physical Solutions (T.I.P.S.), Villach stancon, Wien Law& Consulting Offices Kurt A. Wagner, Villach – Chicago eoVision GmbH, Salzburg College Station (USA) / Department of Geography – Texas A&M University Dept. of Geography – San Diego State University
In viticulture, yield prediction plays an important role, helping winegrowers to predict the star... more In viticulture, yield prediction plays an important role, helping winegrowers to predict the start of the next growth stage of vines and to improve vineyard management decisionmaking. To predict a vineyard's yield, it is necessary to gather accurate local information about the vine's phenology and morphology, such as the volume of individual grapes. Traditional collection of these data and yield prediction rely on resource-and time-intensive direct visual and manual in-field work by viticulturists. Thus, only limited sampling in the vineyards is possible, carried out by humans. Automated procedures utilizing sensor-based systems reduce the data acquisition time and enable the collection of high-resolution data from the entire vineyard. Large-scale 3D models of vineyards can be generated from these data and used to analyse, for example, the vineyard's yield or the vegetative stage of individual vines. We propose a concept for a 3D model that uses close-range photogrammetry. In a laboratory experiment, we tested the acquisition of multi-view image datasets from grapes using close-range photogrammetry and derived physical and morphological parameters from 3D grape models. The results could contribute to the design and implementation of a large-scale in-field experiment.
Image velocimetry has proven to be a promising technique for monitoring river flows using remotel... more Image velocimetry has proven to be a promising technique for monitoring river flows using remotely operated platforms such as Unmanned Aerial Systems (UAS). However, the application of various image velocimetry algorithms has not been extensively assessed. Therefore, a sensitivity analysis has been conducted on five different image velocimetry algorithms including Large Scale Particle Image Velocimetry (LSPIV), Large-Scale Particle Tracking Velocimetry (LSPTV), Kanade-Lucas Tomasi Image Velocimetry (KLT-IV or KLT), Optical Tracking Velocimetry (OTV) and Surface Structure Image Velocimetry (SSIV), during low river flow conditions (average surface velocities of 0.12-0.14 m s −1 , Q60) on the River Kolubara, Central Serbia. A DJI Phantom 4 Pro UAS was used to collect two 30-second videos of the surface flow. Artificial seeding material was distributed homogeneously across the rivers surface, to enhance the conditions for image velocimetry techniques. The sensitivity analysis was performed on comparable parameters between the different algorithms, including the particle identification area parameters (such as Interrogation Area (LSPIV, LSPTV and SSIV), Block Size (KLT-IV) and Trajectory Length (OTV)) and the feature extraction rate. Results highlighted that KLT and SSIV were sensitive to changing the feature extraction rate; however, changing the particle identification area did not affect the surface velocity results significantly. OTV and LSPTV, on the other hand, highlighted that changing the particle identification area presented higher variability in the results, while changing the feature extraction rate did not affect the surface velocity outputs. LSPIV proved to be sensitive to changing both the feature extraction rate and the particle identification area. This analysis has led to the conclusions that for surface velocities of approximately 0.12 m s −1 image velocimetry techniques can provide results comparable
In Austria, more than a half of all electricity is produced with the help of hydropower plants. T... more In Austria, more than a half of all electricity is produced with the help of hydropower plants. To reduce their ecological impact, dams are being equipped with fish passages that support connectivity of habitats of riverine fish species, contributing to hydropower sustainability. The efficiency of fish passages is being constantly monitored and improved. Since the likelihood of fish passages to be discovered by fish depends, inter alia, on flow conditions near their entrances, these conditions have to be monitored as well. In this study, we employ large-scale particle image velocimetry (LSPIV) in seeded flow conditions to analyse images of the area near a fish passage entrance, captured with the help of a ready-to-fly consumer drone. We apply LSPIV to short image sequences and test different LSPIV interrogation area sizes and correlation methods. The study demonstrates that LSPIV based on ensemble correlation yields velocities that are in good agreement with the reference values reg...
Repeat Station Imaging (RSI) for image acquisition is compared with non-RSI to assess the methods... more Repeat Station Imaging (RSI) for image acquisition is compared with non-RSI to assess the methods' effects on vertical and volumetric estimation using structure from motion (SFM). Aerial triangulation (i.e., SFM) is used to create three-dimensional reconstructions of the study area using unmanned aerial vehicle-acquired imagery. Targets of known volume were deployed throughout the scene and manipulated to create changes between the first and subsequent flights. An RSI flight and two non-RSI flights were compared to a baseline flight in order to estimate a series of introduced volumetric changes, which were then compared to known volume changes. Using images with a nominal ground sampling distance of 1.96 cm, results show a total root-mean-squared-error (RMSE) of 0.035 m 3 and mean percent error (MPE) of 25.9% for the RSI flight, and average RMSE of 0.057 m 3 and MPE 33.3% for the two non-RSI flights. For the measurement of volumetric changes to extant features, the RSI flight had an RMSE of 0.026 m 3 and an MPE of 17.6%; the average RMSE and MPE of the two non-RSI flights were 0.071 m 3 and 39.4%. These results show that RSI has the potential to improve the accuracy of volumetric and height change estimation.
Since the turn of the 21 st Century, image based velocimetry techniques have become an increasing... more Since the turn of the 21 st Century, image based velocimetry techniques have become an increasingly popular approach for determining open-channel flow in a range of hydrological settings across Europe, and beyond. Simultaneously, a range of large-scale image velocimetry algorithms have been developed, equipped with differing image pre-processing, and analytical capabilities. Yet in operational hydrometry, these techniques are utilised by few competent authorities. Therefore, imagery collected for image velocimetry analysis, along with validation data is required both to enable inter-comparisons between these differing approaches and to test their overall efficacy. Through benchmarking exercises, it will be possible to assess which approaches are best suited for a range of fluvial settings, and to focus future software developments. Here we collate, and describe datasets acquired from six countries across Europe and Asia, consisting of videos that have been subjected to a range of pre-processing, and image velocimetry analysis (Perks et al., 2019, https://doi.org/10.4121/uuid: 34764be1-31f9-4626-8b11-705b4f66b95a). Validation data is available for 12 of the 13 case studies presented enabling these data to be used for validation and accuracy assessment. 1 Introduction When designing hydrological monitoring networks, or acquiring opportunistic measurements for determining open-channel flow, the optimum choice of apparatus is likely to be a compromise between the data requirements, resource availability, and the hydro-geomorphic characteristics of the site (Mishra and Coulibaly, 2009). Generally, hydro-geomorphic factors will include: channel width and depth, the range of flow velocities, presence of secondary circulation, and cross-section stability.
ISPRS International Journal of Geo-Information, 2017
Over the past few years, analysts have begun to materialize the "Citizen as Sensors" principle by... more Over the past few years, analysts have begun to materialize the "Citizen as Sensors" principle by analyzing human movements, trends and opinions, as well as the occurrence of events from tweets. This study aims to use geo-tagged tweets to identify and visualize refugee migration patterns from the Middle East and Northern Africa to Europe during the initial surge of refugees aiming for Europe in 2015, which was caused by war and political and economic instability in those regions. The focus of this study is on exploratory data analysis, which includes refugee trajectory extraction and aggregation as well as the detection of topical clusters along migration routes using the V-Analytics toolkit. Results suggest that only few refugees use Twitter, limiting the number of extracted travel trajectories to Europe. Iterative exploration of filter parameters, dynamic result mapping, and content analysis were essential for the refinement of trajectory extraction and cluster detection. Whereas trajectory extraction suffers from data scarcity, hashtag-based topical clustering draws a clearer picture about general refugee routes and is able to find geographic areas of high tweet activities on refugee related topics. Identified spatio-temporal clusters can complement migration flow data published by international authorities, which typically come at the aggregated (e.g., national) level. The paper concludes with suggestions to address the scarcity of geo-tagged tweets in order to obtain more detailed results on refugee migration patterns.
The major goal of this exploratory project “Drone Zone Austria” is to design a web portal prototy... more The major goal of this exploratory project “Drone Zone Austria” is to design a web portal prototype as innovative contribution to air traffic management in order to support safe Remotely Piloted Aircraft Systems (RPAS, also known as unmanned aerial systems (UAS) or “drones”) mission planning. The web portal will provide a map-based representation of the legally defined 4 areas of operation for professional and recreational drone missions in Austria (Fig. 1). Furthermore, it will include a flight plan safety check incorporating documentation functionality based on the requirements defined in the legal operation approval.
The topic of geoprivacy is increasingly relevant as larger quantities of personal location data a... more The topic of geoprivacy is increasingly relevant as larger quantities of personal location data are collected and shared. The results of scientific inquiries are often spatially suppressed to protect confidentiality, limiting possible benefits of public distribution. Obfuscation techniques for point data hold the potential to enable the public release of more accurate location data without compromising personal identities. This paper examines the application of four spatial obfuscation methods for household survey data. Household privacy is evaluated by a nearest neighbor analysis, and spatial distribution is measured by a cross-k function and cluster analysis. A new obfuscation technique, Voronoi masking, is demonstrated to be distinctively equipped to balance between protecting both household privacy and spatial distribution.
Simulation of reality in computer games has recently been adopted for urban planning purposes. Mi... more Simulation of reality in computer games has recently been adopted for urban planning purposes. Minecraft™ is a computer game in which players use 1m³ blocks of various materials to construct buildings in an imaginary world. It has become popular recently as a geodesign tool for encouraging public participation in urban planning. As part of this research, a prototype model was developed based on the enhanced transformation of actual spatial datasets into a Minecraft virtual world. A Minecraft-based, collaborative geodesign participatory process was conducted in order to assess a geodesign proposal for a location within the study area in Austria. The research aims to explore the usability of Minecraft as a geodesign tool that can facilitate public participation in urban planning decision support. The results showed that maintaining adequate realism in Minecraft model designs can positively influence users' sense of orientation and improve their navigation in a Minecraft world. A disadvantage of using Minecraft is that assessing the reliability of designs for urban planning is time-consuming. Furthermore, using Minecraft models requires participants to be highly motivated
The rising number of UAS operations in the European airspace poses a safety issue. The key proble... more The rising number of UAS operations in the European airspace poses a safety issue. The key problem is to ensure safe drone traffic management and their integration into the existing air traffic environment. Thus, risk assessment becomes an integral part of every UAS operation and its automation is of great importance when dealing with growing numbers of flights. There exist many attempts to support such risk assessment, but an optimal solution is yet to be found. This paper presents a prototype of a web application, which automates strategic risk assessment of open and specific UAS operations in Austria with the use of open government geodata. Risk assessment results are visualized on a map, showing spatial distribution of classified risks in the operational area. This prototype is the first attempt to combine the functions of a "drone map" representing relevant geodata and a questionnaire usually used to support specific operation risk assessment. There is a potential to turn it into a tool which is used to create a comprehensive preflight safety portfolio or to support the automatic risk assessment performed by a UTM before a UAS operation is checked in. Simplifying the creation of safety portfolios and automating UAS operation risk assessment are important factors in promoting a wider and safer use of UAS.
Accessing geospatial data via the internet is a common way for data integration. This web mapping... more Accessing geospatial data via the internet is a common way for data integration. This web mapping approach often relies on web services like the web map tile service (WMTS) for accessing maps or the web feature service (WFS) for accessing vector data. An alternative way, which combines aspects like the higher performance through tiling and the usage of vector data is the usage of tiled vector data. This short paper describes an approach for the creation of tiled vector data using standard PostgreSQL, with spatial extension PostGIS, functionality. For that, custom PostGIS functions are implemented to select relevant vector data out of the PostgreSQL database, dynamically generalize/simplify geometries and transform the data to Mapbox mvt format. This approach of creating tiled vector data shall be used for further implementations of web maps for building more efficient spatial data infrastructures.
Remotely Piloted Aircraft Systems (RPAS) stellen aktuell ein rasant wachsendes technologisches Ma... more Remotely Piloted Aircraft Systems (RPAS) stellen aktuell ein rasant wachsendes technologisches Marktsegment dar, das speziell im Bereich der hochauflösenden Datenerfassung und des Monitorings enormes Potenzial für zivile Anwendungsmöglichkeiten im Geoinformationsbereich bietet. ZALOGA et al. (2013) schätzen, dass sich der weltweite RPAS Markt in Bezug auf jährliche Investitionsvolumina in neue Beschaffungen und F&E bis 2020 von derzeit (Stand 2013) ca. 5.2 Mrd. US$ auf 11.6 Mrd. US$ verdoppeln wird. In den USA werden durch eine gesetzlich geregelte Integration von RPAS in den zivilen Luftraum ab 2015 in den ersten 3 Jahren mehr als 70,000, und bis 2025 geschätzte 100,000 neue Jobs prognostiziert (AUVSI 2013). Mit der anstehenden nationalen und internationalen Eliminierung von bestehenden Barrieren für den zivilen RPAS-Einsatz werden neue Märkte für unbemannte luftfahrtsystembasierte Dienstleistungen erschlossen. Ausgelöst vom gesetzlich verabschiedeten Vorhaben der USA, zivile RPAS beginnend mit 2015 für Missionen im nationalen Luftraum zuzulassen, hat die Europäische Kommission 2013 eine europaweite Strategie für die Integration von zivilen RPAS Systemen in den europäischen Luftraum verabschiedet (EC-RPAS Roadmap 2013). Ein zentrales Element dieser Strategie ist die notwendige Erweiterung und Anpassung der gesetzlichen Rahmenbedingungen für die sichere Luftraumintegration sowohl auf europäischer als auch nationaler Ebene. Die jeweilige Zuständigkeit richtet sich dabei nach der RPAS-Gewichtsklasse, wobei für RPAS Systeme mit einem Gesamtgewicht größer als 150 kg die europäische Luftfahrtbehörde EASA zuständig ist, für Systeme mit einem Gesamtgewicht kleiner 150kg die jeweilige nationale Luftfahrtbehörde. Vor diesem Hintergrund wurde 2013 eine Novelle zum nationalen Luftfahrtgesetz in Österreich verabschiedet (LFG 2013), und die Austro Control mit der Erarbeitung der spezifischen Durchführungsbestimmungen beauftragt. Diese wurden im Dezember 2013 zur Begutachtung ausgesendet und traten mit 1.1.2014 gesetzlich in Kraft (ACG 2014). In diesen Durchführungsbestimmungen (Lufttüchtigkeits-und Betriebstüchtigkeitshinweis Nr. 67-LTBH 67) ist die Erteilung für Flugbewilligungen für die gewerbliche Nutzung und den Betrieb von unbemannten Luftfahrzeugen (uLFZ) geregelt. Die behördlichen Entscheidungskriterien für die Strenge der Auflagen sowie den Umfang des Bewilligungsprozesses ist eine Kombination aus Betriebsmasse (< 5 kg < 25 kg < 150 kg), Besiedlungsdichte des geplanten Einsatzgebietes (es werden die 4 Klassen unbebaut, unbesiedelt, besiedelt und dicht besiedelt unterschieden), sowie ob während der Mission ein Sichtkontakt mit einer maximale erlaubten Flughöhe von 150m zwischen RPAS und Pilot besteht (Klasse 1) oder nicht (Klasse 2). Abbildung 1 zeigt die daraus resultierende für Österreich gültige Kategorisierung von uLFZ.
Hochauflösende Oberflächenmodelle spielen heute eine große Rolle bei vielen Anwendungen im Bereic... more Hochauflösende Oberflächenmodelle spielen heute eine große Rolle bei vielen Anwendungen im Bereich der Hochwassersimulation, der Gefahrenzonenmodellierung, der Forstwirtschaft oder der Habitatsmodellierung, um nur einige Beispiele zu nennen. Aktuell werden diese Digitalen Oberflächenmodelle (DOM) vorwiegend durch Airborne Laser Scanning (ALS) erfasst und stellen mittlerweile einen immer weiter verbreitenden und flächendeckend verfügbaren Geobasisdatensatz nicht nur in Österreich dar. Speziell eine flächendeckende Erfassung und Nachführung von ALS-Daten ist zeitaufwendig und kostenintensiv, und kommt daher für die quantitative Analyse von raumzeitlichen Veränderungsprozessen nur bedingt infrage.
Riparian forests are critical for carbon storage, biodiversity, and river water quality. There ha... more Riparian forests are critical for carbon storage, biodiversity, and river water quality. There has been an increasing use of very-high-spatial-resolution (VHR) unmanned aircraft systems (UAS)-based remote sensing for riparian forest mapping. However, for improved riparian forest/zone monitoring, restoration, and management, an enhanced understanding of the accuracy of different classification methods for mapping riparian forests and other land covers at high thematic resolution is necessary. Research that compares classification efficacies of endmember- and object-based methods applied to VHR (e.g., UAS) images is limited. Using the Sequential Maximum Angle Convex Cone (SMACC) endmember extraction algorithm (EEA) jointly with the Spectral Angle Mapper (SAM) classifier, and a separate multiresolution segmentation/object-based classification method, we map riparian forests/land covers and compare the classification accuracies accrued via the application of these two approaches to narr...
Waterfowl monitoring is an important task for understanding waterfowl distribution and habitats. ... more Waterfowl monitoring is an important task for understanding waterfowl distribution and habitats. Surveying approaches using hyper-spatial airborne imagery, collected by small unoccupied aerial systems (sUAS), hold potential to overcome the limitations of traditional methods while improving count efficiency and reliability. Difficulties obtaining waterfowl counts, particularly in complex image scenes, from the high quantity of imagery required hinders deployment of large-scale surveys. In this paper, we test Convolutional Neural Networks (CNNs) to understand their potential and how they behave across different versions of our waterfowl dataset. Three CNN architectures (YOLO, Retinanet and Faster R-CNN) were trained on 3 hierarchical levels: waterfowl detection (True / False), waterfowl type (3 classes), and waterfowl species (8 classes). The architectures generally performed well, and results indicate that automated waterfowl detection in complex environments, and therefore enumeration, is feasible using current technology. Waterfowl identification in complex environments was not successful using the available training data, but we propose steps that might enhance the results.
ISPRS International Journal of Geo-Information, 2021
Global sensitivity analysis, like variance-based methods for massive raster datasets, is especial... more Global sensitivity analysis, like variance-based methods for massive raster datasets, is especially computationally costly and memory-intensive, limiting its applicability for commodity cluster computing. The computational effort depends mainly on the number of model runs, the spatial, spectral, and temporal resolutions, the number of criterion maps, and the model complexity. The current Spatially-Explicit Uncertainty and Sensitivity Analysis (SEUSA) approach employs a cluster-based parallel and distributed Python–Dask solution for large-scale spatial problems, which validates and quantifies the robustness of spatial model solutions. This paper presents the design of a framework to perform SEUSA as a Service in a cloud-based environment scalable to very large raster datasets and applicable to various domains, such as landscape assessment, site selection, risk assessment, and land-use management. It incorporates an automated Kubernetes service for container virtualization, comprising...
Flow patterns are an important indicator that helps fish to discover fish ladders. This feasibili... more Flow patterns are an important indicator that helps fish to discover fish ladders. This feasibility study investigates the possibility of a non-intrusive detection of surface flow patterns near a fish ladder in an Alpine river. The newly developed method concept involves the use of high-resolution drone based videos and the optical analysis method “Particle Image Velocimetry” (PIV). The flow patterns calculated with PIV are in good agreement with the hydraulic reference measurements, which were performed with the help of a propeller current meter. The results of this feasibility study can be seen as a first step towards the creation of an efficient and standardized methodology for flow analysis in the vicinity of fish ladders.
The use of UAS at professional as well as recreational level has been risen tremendously in the l... more The use of UAS at professional as well as recreational level has been risen tremendously in the last years. The FAA expects “around 7 million drones flying over America in 2020” (http://www.popsci.com/new-faareportstares-in-face-drone-filled-future ). Based on an estimation of the Austrian Aeroclub there have been about 17,000 drones sold only for recreational use in 2015 in a small country like Austria. This situation might cause an increased risk potential and high expected probability for incidences, especially for urban areas.
Gernot Paulus, Karl-Heinrich Anders, Melanie Regenfelder, Bernhard Kosar, Alexsandra Rieger, Klau... more Gernot Paulus, Karl-Heinrich Anders, Melanie Regenfelder, Bernhard Kosar, Alexsandra Rieger, Klaus Michor, Wolfgang Werth, Christoph Ungermanns, Hermann Sterner, Gerhard Hohenwarter, Christian Stefan, Rainer Gaggl, Heinz Stanek, Kurt Wagner, Markus Eisl, Anthony Fillipi, Inci Güneralp und André Skupin FH Kärnten – Geoinformation und Umwelttechnologien, Villach · [email protected] FH Kärnten – Systems Design, Villach REVITAL Integrative Naturraumplanung GmbH, Lienz ZAMG, Klagenfurt Technical Innovation – Physical Solutions (T.I.P.S.), Villach stancon, Wien Law& Consulting Offices Kurt A. Wagner, Villach – Chicago eoVision GmbH, Salzburg College Station (USA) / Department of Geography – Texas A&M University Dept. of Geography – San Diego State University
In viticulture, yield prediction plays an important role, helping winegrowers to predict the star... more In viticulture, yield prediction plays an important role, helping winegrowers to predict the start of the next growth stage of vines and to improve vineyard management decisionmaking. To predict a vineyard's yield, it is necessary to gather accurate local information about the vine's phenology and morphology, such as the volume of individual grapes. Traditional collection of these data and yield prediction rely on resource-and time-intensive direct visual and manual in-field work by viticulturists. Thus, only limited sampling in the vineyards is possible, carried out by humans. Automated procedures utilizing sensor-based systems reduce the data acquisition time and enable the collection of high-resolution data from the entire vineyard. Large-scale 3D models of vineyards can be generated from these data and used to analyse, for example, the vineyard's yield or the vegetative stage of individual vines. We propose a concept for a 3D model that uses close-range photogrammetry. In a laboratory experiment, we tested the acquisition of multi-view image datasets from grapes using close-range photogrammetry and derived physical and morphological parameters from 3D grape models. The results could contribute to the design and implementation of a large-scale in-field experiment.
Image velocimetry has proven to be a promising technique for monitoring river flows using remotel... more Image velocimetry has proven to be a promising technique for monitoring river flows using remotely operated platforms such as Unmanned Aerial Systems (UAS). However, the application of various image velocimetry algorithms has not been extensively assessed. Therefore, a sensitivity analysis has been conducted on five different image velocimetry algorithms including Large Scale Particle Image Velocimetry (LSPIV), Large-Scale Particle Tracking Velocimetry (LSPTV), Kanade-Lucas Tomasi Image Velocimetry (KLT-IV or KLT), Optical Tracking Velocimetry (OTV) and Surface Structure Image Velocimetry (SSIV), during low river flow conditions (average surface velocities of 0.12-0.14 m s −1 , Q60) on the River Kolubara, Central Serbia. A DJI Phantom 4 Pro UAS was used to collect two 30-second videos of the surface flow. Artificial seeding material was distributed homogeneously across the rivers surface, to enhance the conditions for image velocimetry techniques. The sensitivity analysis was performed on comparable parameters between the different algorithms, including the particle identification area parameters (such as Interrogation Area (LSPIV, LSPTV and SSIV), Block Size (KLT-IV) and Trajectory Length (OTV)) and the feature extraction rate. Results highlighted that KLT and SSIV were sensitive to changing the feature extraction rate; however, changing the particle identification area did not affect the surface velocity results significantly. OTV and LSPTV, on the other hand, highlighted that changing the particle identification area presented higher variability in the results, while changing the feature extraction rate did not affect the surface velocity outputs. LSPIV proved to be sensitive to changing both the feature extraction rate and the particle identification area. This analysis has led to the conclusions that for surface velocities of approximately 0.12 m s −1 image velocimetry techniques can provide results comparable
In Austria, more than a half of all electricity is produced with the help of hydropower plants. T... more In Austria, more than a half of all electricity is produced with the help of hydropower plants. To reduce their ecological impact, dams are being equipped with fish passages that support connectivity of habitats of riverine fish species, contributing to hydropower sustainability. The efficiency of fish passages is being constantly monitored and improved. Since the likelihood of fish passages to be discovered by fish depends, inter alia, on flow conditions near their entrances, these conditions have to be monitored as well. In this study, we employ large-scale particle image velocimetry (LSPIV) in seeded flow conditions to analyse images of the area near a fish passage entrance, captured with the help of a ready-to-fly consumer drone. We apply LSPIV to short image sequences and test different LSPIV interrogation area sizes and correlation methods. The study demonstrates that LSPIV based on ensemble correlation yields velocities that are in good agreement with the reference values reg...
Repeat Station Imaging (RSI) for image acquisition is compared with non-RSI to assess the methods... more Repeat Station Imaging (RSI) for image acquisition is compared with non-RSI to assess the methods' effects on vertical and volumetric estimation using structure from motion (SFM). Aerial triangulation (i.e., SFM) is used to create three-dimensional reconstructions of the study area using unmanned aerial vehicle-acquired imagery. Targets of known volume were deployed throughout the scene and manipulated to create changes between the first and subsequent flights. An RSI flight and two non-RSI flights were compared to a baseline flight in order to estimate a series of introduced volumetric changes, which were then compared to known volume changes. Using images with a nominal ground sampling distance of 1.96 cm, results show a total root-mean-squared-error (RMSE) of 0.035 m 3 and mean percent error (MPE) of 25.9% for the RSI flight, and average RMSE of 0.057 m 3 and MPE 33.3% for the two non-RSI flights. For the measurement of volumetric changes to extant features, the RSI flight had an RMSE of 0.026 m 3 and an MPE of 17.6%; the average RMSE and MPE of the two non-RSI flights were 0.071 m 3 and 39.4%. These results show that RSI has the potential to improve the accuracy of volumetric and height change estimation.
Since the turn of the 21 st Century, image based velocimetry techniques have become an increasing... more Since the turn of the 21 st Century, image based velocimetry techniques have become an increasingly popular approach for determining open-channel flow in a range of hydrological settings across Europe, and beyond. Simultaneously, a range of large-scale image velocimetry algorithms have been developed, equipped with differing image pre-processing, and analytical capabilities. Yet in operational hydrometry, these techniques are utilised by few competent authorities. Therefore, imagery collected for image velocimetry analysis, along with validation data is required both to enable inter-comparisons between these differing approaches and to test their overall efficacy. Through benchmarking exercises, it will be possible to assess which approaches are best suited for a range of fluvial settings, and to focus future software developments. Here we collate, and describe datasets acquired from six countries across Europe and Asia, consisting of videos that have been subjected to a range of pre-processing, and image velocimetry analysis (Perks et al., 2019, https://doi.org/10.4121/uuid: 34764be1-31f9-4626-8b11-705b4f66b95a). Validation data is available for 12 of the 13 case studies presented enabling these data to be used for validation and accuracy assessment. 1 Introduction When designing hydrological monitoring networks, or acquiring opportunistic measurements for determining open-channel flow, the optimum choice of apparatus is likely to be a compromise between the data requirements, resource availability, and the hydro-geomorphic characteristics of the site (Mishra and Coulibaly, 2009). Generally, hydro-geomorphic factors will include: channel width and depth, the range of flow velocities, presence of secondary circulation, and cross-section stability.
ISPRS International Journal of Geo-Information, 2017
Over the past few years, analysts have begun to materialize the "Citizen as Sensors" principle by... more Over the past few years, analysts have begun to materialize the "Citizen as Sensors" principle by analyzing human movements, trends and opinions, as well as the occurrence of events from tweets. This study aims to use geo-tagged tweets to identify and visualize refugee migration patterns from the Middle East and Northern Africa to Europe during the initial surge of refugees aiming for Europe in 2015, which was caused by war and political and economic instability in those regions. The focus of this study is on exploratory data analysis, which includes refugee trajectory extraction and aggregation as well as the detection of topical clusters along migration routes using the V-Analytics toolkit. Results suggest that only few refugees use Twitter, limiting the number of extracted travel trajectories to Europe. Iterative exploration of filter parameters, dynamic result mapping, and content analysis were essential for the refinement of trajectory extraction and cluster detection. Whereas trajectory extraction suffers from data scarcity, hashtag-based topical clustering draws a clearer picture about general refugee routes and is able to find geographic areas of high tweet activities on refugee related topics. Identified spatio-temporal clusters can complement migration flow data published by international authorities, which typically come at the aggregated (e.g., national) level. The paper concludes with suggestions to address the scarcity of geo-tagged tweets in order to obtain more detailed results on refugee migration patterns.
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Papers by Gernot Paulus