Proceedings of the Institute of Geodesy and Cartography - No 105, Vol. XLIX
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Jan Kryński
Satellite mission CHAMP – first results and research perspectives
Satellite CHAMP, launched on 15 July 2000, began the first space mission dedicated to the complex research of the Earth as a system composed of solid, liquid and gaseous parts that show large variation in space and time and mutual complex interactions taking place on quite different time scales, by the use of measuring instruments operating on board of a low satellite. Research topics related to CHAMP mission concentrate on the investigation of gravity and magnetic field of the Earth including their time variability as well as on the investigation of the structure and dynamics of neutral atmosphere and ionosphere. Advance in research projects and discussion of the results obtained after first 18 months of mission were the subjects of scientific conference in Potsdam in January, 2002. The paper gives a review of scientific and technical problems related with the mission and discussed during the conference as well as the results obtained and expected from the rest of the mission.
Jerzy Janusz
Scale errors in linear networks for determining horizontal displacements
Author presented discussion concerning approach related to identification of fixed points in horizontal networks, which include linear observations. It was emphasized, that applying for this purpose four-parameter conformal transformation only points, which form figure with the similar shape, can be identified, while usage of three-parameter isometric transformation enables identification of figure not only with similar shape, but also with original size.
It implies application for identification of fixed points and for calculation of displacements of the remaining network points three-parameter isometric transformation. It is possible to admit use four-parameter conformal transformation for this purpose, but then coefficient of change of scale must be calculated and checked, if its value is different from 0 within negligible limits, not influencing the computed displacements. The example was given in the paper, which illustrates consequences of applying four-parameter transformation in case, when figure formed by points of updated network is not identical with figure formed by these points in original network, being only similar in shape.
In case, when network is characterized by repeating orientation observations, i.e. astronomical azimuths, GPS satellite observations or observations of directions to distant earth targets, identification of fixed points should be based on searching for figures, which kept unchanged size and orientation. Then identification of fixed points and calculation of displacements of the remaining points should be done with the use of two-parameter transformation.
Jerzy Janusz
Linear trigonometric levelling
Author presented concept of making levelling traverses applying method of linear trigonometric levelling with the use of electronic tacheometer and two mirrors with targets on poles of the same height. Advantages of the method, especially in the areas with big slopes, where keeping distance between instrument and mirrors as in flat terrain becomes possible, were described. The other advantages were also mentioned: possibility to replace 3 m staffs with more portable mirrors on 1.6 m poles, which corresponds to the average height of axis of rotation for tacheometer set on tripod, as well as option of avoiding staff calibration and instead of it checking, if heights of mirrors on poles are the same. Prognosis of possible high accuracies, while applying linear trigonometric leveling, was presented.
Bogdan Dobrowolski
Concept of digital model of track geometry in the process of surface repair
Author discusses in the article problem of geodetic service in the course of repairs of tracks used for fast trains.
In order to understand better criteria of accuracy requirements, concerning determination of axes of tracks, and in consequence selection of geodetic methods fulfilling these requirements, author presents briefly basic definitions characterizing geometrical axis of track. In particular definition of curvature of geometrical track axis is important, as well as method of its measurement and related problems of long-wave deformations. Advantages and disadvantages of algorithms of programs applied for regulation of track axis, which use involute and geodetic coordinate systems, were discussed. Criterion of continuity of curvature is the most important for measurement accuracy of track axis. Joint application of this criterion with requirement of elimination of long-wave deformations of geometrical track axis creates strict accuracy conditions for measurements. These requirements are met by the Special Railway Control Network and hence by measurements of track axes attached to this network, discussed in this article. Furthermore, the problem is concentrated on geodetic service of track devices used for moving and lifting tracks, which also must meet high accuracy requirements. For these works “total station” or GPS receiver can be used. Author created the concept of digital model of track geometry, which includes sets of points of track axis and gauge of constructions extracted from digital railway map. Each repair would update the model and in consequence digital map. Full benefits from implementing the concept would be visible after improvement of height measurements with the use of GPS system.
Albina Mościcka
Application of Flash technology for preparation of Interactive Landscape Map of Karkonoski National Park
Development of internet, as well as advances in electronics caused dynamic changes also in cartography. Paper map lost its dominant role among cartographic materials. It became form less attractive, comparing to its interactive and multimedia digital equivalents. Cartographic products are presented in www network mainly in the form of different maps.
Program Macromedia Flash is a tool, which gives great possibilities for presentation of cartographic data on internet pages. This program enables to design whole www pages and to have their direct record in HTML format. Such a designing of internet pages has great advantages. Pages prepared with the use of Flash automatically match windows of user viewer, so most of internet users can view Flask files without installing additional plug-in.
Undoubtedly, the most important feature of Macromedia Flash is, that it makes possible, with no limits, to supplement data with interactive elements, which enables user to select the displayed elements, and with dynamic elements, allowing for change of page contents in real-time through application of various navigation methods.
Possibility of using in internet vector graphics is also the important advantage of Flash technology. It enables significant decrease of file size, as well as it allows for entering elements, which enrich map contents.
Possibilities of application of Flash technology for cartographic presentations were practically verified in the course of preparation of Interactive Landscape Map for Karkonoski National Park.
Anna Wrochna, Waldemar Rudnicki
Visualization of landscape with perspective method applying aerial and satellite images with the use of new computer techniques
Authors present in the article results of research project, aimed at preparation of method of perspective visualization of landscape, applying aerial and satellite images with the use of new computer techniques.
Digital terrain models (NMT), which were created recently, allow for making map contents with simulated spatial effect and for their better perception. These models can be useful for landscape visualization. Panoramic images prepared so far with the use of conventional methods are almost no more produced. Present tools and achievements of computer science, as well as possibilities of using aerial and satellite images create basis for developing new methods for landscape presentation or for modifying old ones.
Perspective method as a tool for visual presentation of landscape is important for popularizing knowledge on attractions of home landscape and on its unique features.
Image information can be the main form of landscape description; it should not only organize thinking, but also support process of getting and deepening knowledge about natural environment.
Authors present in the article two methods of landscape visualization: panorama and perspective.
Process of preparation of source data, as well as work flow aimed at method of perspective landscape visualization with the use of aerial and satellite images, was presented.
Examples of perspectives for one of three test sites (surroundings of Bukowka Lake) were demonstrated.