Andrzej Stepnowski

Interactive visualization of marine pollution monitoring and forecasting data via a Web-based GIS

This work implements a Web-based Geographic Information System (Web GIS) for an existing oil spill monitoring and forecasting service, developed in the framework of the MARCOAST project. This is achieved by remotely presenting the results of the oil spill forecasting module via a dedicated Web GIS, which allows authenticated end users to view the simulation results in a geographical context. A number of Web GIS technologies for presentation of dissimilar types of semi-dynamic geographic data are applied and their respective capabilities for publishing and remote presentation of interactive geospatial information, such as oil spill spread animation overlaid on background data (terrain elevation data, satellite imagery, etc.), are described. More specifically, technologies like ESRI^(R) ArcIMS^(R) (Arc Internet Map Server) and Open Source GeoServer with OpenLayers client library are implemented. The capabilities of the system for visualization and mapping are illustrated by specific applications concerning the spreading scenarios of oil spills in two selected areas of the Aegean Sea, Greece. The presented Web GIS offers added value in the form of providing the end user with comprehensive and synthetic, both spatial and temporal, environmental information through a remotely customizable user-friendly graphical interface. In this context, its integration to a marine pollution monitoring and forecasting system could result in an enhanced pollution awareness and emergency management tool.

Innovative Web-Based Geographic Information System for Municipal Areas and Coastal Zone Security and Threat Monitoring Using EO Satellite Data

The paper presents a novel design of a web-based Safe City & Coastal Zone GIS (SCCZ-GIS). The system integrates data acquired from different remote sensing and geospatial data sources for the purpose monitoring the security of the coastal zone, its inhabitants and critical infrastructure. The system utilizes several innovative technologies and solutions and is capable of direct co-operation with different remote sensing data sources and services, including satellite ground station and ESA Service Support Environment. The system runs in operational mode, and the results of the analysis are ready in quasi real time, that is, immediately after receiving a new scene of satellite imagery. The system may be accessed by authorized users either through a web-based client or mobile device application. The paper describes the architecture of the system and presents several case studies where the software is applied to processing of earth observation satellite and spatial analysis of coastal zone infrastructure.

Geographical Information System for analysis of Critical Infrastructures and their hazards due to terrorism, man-originated catastrophes and natural disasters for the city of Gdansk

The paper presents a web-based Geographic Information System (GIS) for assessment and visualization of Critical Infra structure (CI) and its hazards which was developed by the Department of Geoinformatics at Gdansk University of Technology for the City of Gdansk. The system allows spatial processing and mapping of various CI analysis results, with the CI analysis module based on the CARVER2™ technology adapted to particular requirements of the Gdansk City Hall Crisis Management Department (CMD). The system works as an integrated solution for both visualization of hazard scenarios and a team-enabled environment for information analysis and sharing among geographically distributed decision makers. The paper focuses on the sample applications with reference to the analysis, visualization, and mapping in a geographical context of several threat scenarios, such as blast attack, chemical attack, and toxic leakage as well as the spatial distribution of critical infrastructure components in Gdansk, Poland.

Inverse problem solution techniques as applied to indirect in situ estimation of fish target strength.

In situ indirect methods of fish target strength (TS) estimation are analyzed in terms of the inverse techniques recently applied to the problem in question. The solution of this problem requires finding the unknown probability density function (pdf) of fish target strength from acoustic echoes, which can be estimated by solving the integral equation, relating pdfs of echo variable, target strength, and beam pattern of the echosounder transducer. In the first part of the paper the review of existing indirect in situ TS-estimation methods is presented. The second part introduces the novel TS-estimation methods, viz.: Expectation, Maximization, and Smoothing (EMS), Windowed Singular Value Decomposition (WSVD), Regularization and Wavelet Decomposition, which are compared using simulations as well as actual data from acoustic surveys. The survey data, acquired by the dual-beam digital echosounder, were thoroughly analyzed by numerical algorithms and the target strength and acoustical backscattering length pdfs estimates were calculated from fish echoes received in the narrow beam channel of the echosounder. Simultaneously, the estimates obtained directly from the dual-beam system were used as a reference for comparison of the estimates calculated by the newly introduced inverse techniques. The TS estimates analyzed in the paper are superior to those obtained from deconvolution or other conventional techniques, as the newly introduced methods partly avoid the problem of ill-conditioned equations and matrix inversion.

Real-time Web-based GIS for Analysis, Visualization and Integration of Marine Environment Data

Visualization and integration of the marine spatial data collected by various marine sensors and sources is an important factor in the context of marine environment sensing and monitoring. Several approaches and techniques of measurements are available to achieve this purpose including direct sampling, airborne and satellite imagery, and underwater acoustics. The paper briefly describes the state-of-the art marine GIS system developed in the Department of Geoinformatics of Gdansk University of Technology, Poland. The proposed system is able to integrate many different types of marine data, especially those acquired by various acoustic sensors like multibeam sonar (MBSS), echosounder and side scan sonars (SSS), and other external sensors such as satellite data receiver, radar, or automated identification of ships (AIS) data analyzer. Instantaneous 2D and 3D visualization is provided by the two components of the system: GeoServer web-based module and a standalone application basing on ESRI ArcGIS Engine solutions.

Computer Vision Techniques Applied for Reconstruction of Seafloor 3D Images from Side Scan and Synthetic Aperture Sonars Data

The Side Scan Sonar and Synthetic Aperture Sonar are well known echo signal processing technologies that produce 2D images of the seafloor. Both systems combines a number of acoustic pings to form a high resolution image of seafloor. It was shown in numerous papers that 2D images acquired by such systems can be transformed into 3D models of seafloor surface by algorithmic approach using intensity information, contained in a grayscaled images. The paper presents the concept of processing the Side Scan Sonar and Synthetic Aperture Sonar records for detailed reconstruction of 3D seafloor using Shape from Shading techniques. Shape from Shading is one of the basic techniques used in computer vision for the objects reconstruction. The algorithms proposed in the paper use the assumed Lambert model of backscattering strength dependence on incident angle and utilize additionally the information from shadow areas for solving obtained set of equations. The idea was verified by simulation study. The obtained results ...

GIS for remote sensing, analysis and visualisation of marine pollution and other marine ecosystem components

Pollution detection, environment sensing and appropriate response strategies are important due to the marine ecosystemspsila continuous absorption of pollutants of various origins. Several approaches and techniques of measurements are available for marine environment monitoring including direct sampling, airborne and satellite imagery and underwater acoustics. The huge development in the information technology has provided the possibilities for much faster and more efficient access to survey data, allowing their remote, nearly real-time management, processing and visualisation. The proposed GIS is able to integrate many different types of marine pollution survey data, especially those acquired by various acoustic sensors like Multibeam Sonar Systems (MBSS), echosounder and Side Scan Sonars (SSS). It also supports instantaneous 2D and 3D visualisation in the form of thematic layers that can be overlaid. The system utilises the ArcSDE application server that facilitates storing and managing spatial data (raster, vector, and survey) in a database and ArcGIS Engine GlobeControl and MapControl components for georeferenced presentation of various objects. The set of geoprocessing and spatial analysis methods can be used in order to retrieve relevant information and analysis results.

Military sonar upgrading methods developed at Gdansk University of Technology

The fast development of electronic technology and digital signal processing methods makes electronic devices, including sonar systems, obsolete very quickly. But because the ships and mechanical components of sonars are operational for a few dozens of years, it makes perfect sense to modernize these devices by using modern components and signal processing methods and overhaul antenna and mechanical systems. The paper presents examples of modernizing sonar systems implemented at Gdansk University of Technology.

Integrated visualization and analysis of threats for marine and coastal regions via a Web-based GIS

The paper presents a Web-Based Geographic Information System for integration, visualization and analysis of data on terrorist, ecological and natural threats. The system uses Open Source solutions like the GeoServer internet map server and the OpenLayers Javascript GIS client library to provide easily accessible and up-to date information related to a region of interest. The system is composed of modules which provide the following features: (1) blast and chemical attack simulation; (2) creation of hazard distribution maps; (3) analysis of risk propagation. Apart from hazard information, which maybe obtained from the simulation modules as well as inserted manually, the system collects and integrates data from several external sensors. The latter include a satellite ground station, oil spill simulation models, a radar and Automated Identification of Ships (AIS). The open, modular structure of the system allows for easy inclusion of different data sources, such as Multibeam Sonar Systems (MBSS) and echosounder. The paper presents case studies of the system applications for analysis, visualization and mapping of threats in the coastal area of the city of Gdansk, Poland.

Nearly real-time, safety-related, remotely accessible marine GIS

The paper presents the prototype of safety-related application of the newly developed real-time, remotely accessible marine GIS for water pollution monitoring and emergency management supporting. The system is able to integrate many different types of marine pollution survey data, including those acquired by acoustic sensors. It processes the data extracted from acoustic echo signals and supports the instantaneous 2/sup D/ and 3/sup D/ visualisation and mapping of pollution aggregations (oil spills, discharge material plumes etc.). It also deals with the multi aspect data management and data analysis, and the prediction of the pollutants behaviour. The system makes use of the SQL database standard for data storage and the Scalable Vector Graphics (SVG) and Virtual Reality Modelling Language (VRML) for geographical objects remote presentation. Moreover, it requires only the WWW browser with SVG and VRML plug-in on the client side.