Václav Talhofer

Improvement of digital geographic data quality

The article focuses on the study of characteristics of digital geographical data and the influence of these characteristics on the quality of the basis being ready for the decision-making processes. Characteristics of digital geographical data are mainly described from the point of view of their technical parameters and keeping the technological indicators while obtaining them. Our system brings a users view into the assessment of characteristics. We define users requirements on data and suggest the system of their evaluation. The assessment of data characteristics comes out of the standard ISO 19113 and the theory of value analysis. Both systems are joined into a complex system for data evaluation. Technical characteristics of data are evaluated mainly by the level of accomplishment of qualitative indicators, e.g. meeting all requirements of horizontal and vertical mean square error, or by completeness of filling of all expected information. Meeting all users’ requirements is usually expressed by the level of users satisfaction with the particular product. This level is set based on the survey among users. Simultaneously, the weight of the individual evaluating criteria is set according to specific types of solved tasks. The system of data evaluation is supplemented with a system of calculation of costs that are needed for obtaining the data. It is possible, however, to work either with the complete database, or to count also the influences of particular groups of data (e.g. communications, residential buildings, etc.) on the complete quality of the final product. The system of costs calculation and evaluation of data quality then enables the optimisation of the use of funds or disposable time for obtaining quality data. The use of the complete system is presented in a pilot project in which a model of terrain passability by a military heavy vehicle is solved.

Usage of fuzzy spatial theory for modelling of terrain passability

Geographic support of decision-making processes is based on various geographic products, usually in digital form, which come from various foundations and sources. Each product can be characterized by its quality or by its utility value for the given type of task or group of tasks, for which the product is used. They also usually have different characteristics and thus can very significantly influence the resulting analytical material. The aim of the paper is to contribute to the solution of the question of how it is possible to work with diverse spatial geographic information so that the user has an idea about the resulting product. The concept of fuzzy sets is used for representation of classes, whose boundaries are not clearly (not sharply) set, namely, the fuzzy approach in overlaying operations realized in ESRI ArcGIS environment. The paper is based on a research project which is being solved at the Faculty of Military Technologies of the University of Defence. The research deals with the influence of geographic and climatic factors on the activity of armed forces and the Integrated Rescue System.

Decision-Making Process with Respect to the Reliability of Geo-Database

The aim of this paper is to propose a method that would focus on data and spatial information precision and reliability evaluation. The resulting characteristics of data reliability can be applied in various command and control systems. The method to contribute to increase the quality of decision-making process is proposed. Finally, the case scenario is focused on an intervention of a fire rescue unit and presents the proposal for the use of the system in practice.

Mathematical Model Used in Decision-Making Process with Respect to the Reliability of Geodatabase

The first aim of the article is to show how it is possible - thanks to the use of sophisticated analytical tools for evaluation of data quality - to better understand geospatial data. Another aim is to assess the impact of data quality on the results of space analyses that are made of them and that are the basis for such decision-making processes, in which it is necessary to take into account the impact of geographical environment.

SPATIAL DATA INFRASTRUCTURE AND GEOVISUALIZATION IN EMERGENCY MANAGEMENT

Support for an emergency management (EM) is one of the important requests for contemporary cartography. Map use demands high flexibility during emergency situations and variety of outputs according to changing situations, requested scope of decision making, and various users involved. Electronic maps are offering more flexible possibilities than traditional analogue maps, but nowadays, despite huge data sources for EM are Geographic Information Systems (GIS) based, still many cartographic interfaces are even less efficient copies of former analogue maps. At the base of this analysis, the focus on the role of GIS, geovisualization, and sensor technologies in emergency management is overviewed. Global description of positional accuracy, projection handling, geodata harmonization, and quality management for EM are described.

Spatial Database Quality and the Potential Uncertainty Sources

One of the most significant features of geo-information systems is the creation of geospatial analyses. The analyses are based on fundamental geospatial data which model the landscape in the certain territory of interest. The analyses themselves are often described by a mathematical apparatus which uses a wide range of branches of mathematics, especially vector analysis, differential geometry, statistics, probability, fuzzy logic, etc. The classical mathematical description of analysis is clear and precisely defined. Complex geospatial analyses, however, work above geospatial data that do not have to be homogeneous from the point of view of quality. With respect to the capacity and technological possibilities of the data supplier, the input data can have different level of geometric and thematic accuracy, their thematic attributes can remain unfulfilled or the data can be obsolete to a certain extent. Also the location of objects (e.g. forested areas, soil, water area, etc.) can be uncertain concerning the impossibility to define them accurately (e.g. areas of different soil kinds are blended together) or change with time (coast line of watercourse that changes depending on rainfall). The stated imprecision and uncertainty then influence the result of the complete geospatial analysis. This influence gets bigger with the number of input data objects.

Verification of digital analytical models: Case study of the cross-country movement

One of the fundamental tactical activities is manoeuver. Reliable geospatial information enables to support decision-making of commanders including manoeuvers planning. Geographic information systems allow modelling of an influence of the individual terrain components on movement of military vehicles depending on their technical and tactical characteristics. The quality of data sources and used models is necessary to consider in such as modelling. The Department of Military Geography and Meteorology at the University of Defence in Brno is focusing its research to this domain. The paper deals with verification of complex models of the Cross-Country Movement that were created using standard digital geographic data for typical vehicles being used in the Czech Army.

Perceptions of Various Cartographic Representations Under Specific Conditions

Maps are usually better abstractions of reality than other media and allow easier perception of included spatial information. This fact makes maps convenient for several specialised societal purposes, including emergency management and transportation, among others.

Terrain Analysis for Armed Forces

The main activities of armed forces take place in the terrain. Knowledge of terrain impact on such activities is very substantial for their achievement. Terrain impact on chosen activities can be described using mathematical models and these can be applied in GIS. Beside the quality of mathematical models, the quality of used data, mainly their vagueness, has fundamental influence on final results of terrain analysis. When calculating parameters for complex models, it is necessary to consider data quality which influences the level of vagueness of the resulting calculations. To express this level of vagueness, a method of fuzzy logic was chosen and then fuzzy functions were used when calculating chosen tasks—model of terrain passability and model of helicopter landing sites selection. The complete procedures were applied in the environment of ArcGIS 10.

Simulation of Laser Attacks against Aircrafts

Threats of laser attacks against transport planes are increasing around the world in the last time. Common laserpointers are used for suchattacks, which emit a continuous greenlaserbeam with the wavelength of λ = 532 nm, and the power emitted is hundreds of milliwatts. This situation is dealing with laws in many countries. The goal of the paper is to contribute to a solution to these dangerous situations for air traffic. The spatial analysis is possible to create in which the configuration of the landscape surrounding the airport, the position of the landing airplane, and parameters of irradiation are considered. The results identify locations from where suchattacks are possible. Such results can aid police by increasing their efficiency in intervening against laser attackers.