Proceedings of the Institute of Geodesy and Cartography - No 109, Vol. LI
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Wojciech Janusz
Method of calculating vertical displacements and deformations of construction foundations with identification and considering symptoms of its discontinuity
Method of calculating displacements and deformations of foundations on the basis of the measured settlements (vertical displacements dH) of stabi-lized benchmarks, was presented in the article. In case, when foundation con-sists of individual monolithic fragments, separated by expansion gaps or di-vided due to deep cracks, the analysis aimed at identification of these frag-ments is done. For this purpose the following procedure is applied: 3 parame-ters of displacements of each potentially undisturbed fragment are calculated for many benchmark combinations, i.e. its changes of inclination dφx, dφy along axes of orthogonal system of horizontal coordinates x, y and vertical displacement at the center of coordinate system dHo. Moreover, the check is done, which fragments of foundations do not reveal vertical deformations –vdH in places, where benchmarks were stabilized.
Fragments of foundation, which do not reveal vertical deformations greater than errors of their determination, are recognized as undisturbed, i.e. monolithic. Fragments slightly disturbed – within their limits of elasticity – are also recognized as monolithic. Next, on the basis of the determined pa-rameters of displacements of monolithic fragments of foundations mutual displacements in the zones of cracks are calculated, as well as differences of angles and horizontal inclinations of these fragments are computed.
The method enables to identify, on the basis of the measured bench-mark settlements, cracks of foundation, which cause its division into separate, monolithic parts, even in cases when other symptoms of such a division are not visible (for instance when division is caused by many tiny cracks, which do not appear as deep cracks, separating monolithic, undisturbed parts of foundation).
Jan Kryński, Maciej Moskwiński, Yevgen M. Zanimonskiy
Analysis of a long-standing series of rotational time determination at Borowa Gora Observatory
The paper presents the attempt to summarize the results of long-standing astronomical observations conducted since 1963 with the passage instrument at Borowa Gora Geodetic-Geophysical Observatory of the Institute of Geodesy and Cartography. A brief historical review that consists of the description instrumental, technological and methodical improvements in ac-quiring and pre-processing of rotational time observations from Borowa Gora Observatory as well as previous use of those observations precedes the main part of the paper devoted to the analysis of the data. Retained observational data and results of pre-processing was carefully investigated in terms of its usefulness for complex analysis. Re-ordering, verification and archiving the existing data as well as transforming it from FK5 catalogue system to the Hipparcos catalogue system became crucial for processing and analysing the retained data that contains the unique information on time variation of astro-nomical latitude of Borowa Gora Observatory; data series from last 19.5 years is particularly valuable for the analysis.
Summary and discussion of previous results of determination of astro-nomical longitude of Borowa Gora are given in the paper. Systematic error of determination of astronomical longitude of Borowa Gora was estimated and conventional value of astronomical longitude of the passage instrument at Borowa Gora was discussed; new conventional value of astronomical longi-tude of the passage instrument at Borowa Gora has been suggested. The solu-tions for the coefficients of the Borowa Gora Observatory equation were ana-lysed. Complex spectral analysis of a long-standing rotational time data series from 1986.0-2005.5 was performed. A number of periodic terms were sepa-rated from the series investigated and the numerical model of the series has been formed.
Ireneusz Ewiak, Romuald Kaczyński
Determination of the range of geometric correction in case of Ikonos and Quickbird Images
Authors presented in the article the method of geometric correction of panchromatic high-resolution satellite images collected by Ikonos and Quick-Bird satellite systems. Data file in each system comprises image matrix and Rational Polynomial Coefficients, which define strict relation between image coordinates of the scene and system of terrain coordinates.
Geometrical accuracy of each image matrix was determined, as well as range of correction for various methodical approaches, which take into ac-count photogrammetric measurements of ground control points.
In particular variants of geometric correction the following elements were used: strict mathematical model of each sensor (Toutin model in PCI Geomatica software), Rational Polynomial Coefficients delivered by data distributor and those determined on the basis of measurements of image co-ordinates related to ground control points.
In each variant analysis concerning impact of number and distribution of ground control points on accuracy of scene orientation was conducted.
It was proved, that optimal result of orientation of Ikonos scene is ob-tained using set of Rational Polynomial Coefficients corrected by results of photogrammetric measurements of 5 ground control points, while for geomet-ric correction of QuickBird scene optimal result is achieved using strict mathematical model of sensor with a set of 9 ground control points symmetri-cally distributed across the scene.
It was found, that range of geometrical correction is larger for Ikonos scene, whereas geometric accuracy of both corrected images is similar.
Anna Wrochna
Rules of selecting contents of base map for cartographic presentations of thematic maps
Since many years problem of preparing base maps has been a subject of interest for map producers. It appears each time while preparing various the-matic maps, especially with regional and national extent, when thematic as-pects are presented on the background of topographic maps with high degree of generalization.
Computer technologies created possibilities of preparing digital base map of Poland with universal map contents. This map would be a basis for creating in a highly automated way base maps with level of detail selected accordingly to the contents of thematic maps.
Rules of selecting contents of base map play an important role, as they imply mechanism related to determination of criteria of choosing map con-tents and its generalization. They have influence on classification of compo-nents of particular thematic layers and on selection of the contents derived from digital base map in order to generate different base maps designed for thematic studies.
The conducted investigations enable to formulate methodical assump-tions for selecting contents and structure of such a digital base map, which will serve as universal topographic base with possibility of generating various base maps at scales from 1:200 000 to 1:1 000 000.
On the basis of analysis of components of topographic maps rules of se-lecting map contents from digital base map of Poland were formed, as well as structure of a database including map elements was determined. This data-base is composed from thematic layers and related, accordingly selected and classified components of base map contents.
Albina Mościcka
Application of information stored in spatial reference grid to preparation of vector thematic maps
Preparation of vector thematic map, using information stored in spatial reference grid, implied utilization of commonly applied rules of generaliza-tion. It was assumed, that first method of preparation of thematic layer, repre-senting phenomena in raster form in spatial reference grid must be deter-mined, and next rules of converting raster image to vector one should be de-fined in such a way, to eliminate raster form of cartographic presentation.
In order to study correctness of the assumptions applied in the proposed method vector thematic map has been prepared; it was based on information stored in the Database of Marginal Soils (administration map of swietokrzy-skie voivodship). In order to distinguish areas belonging to particular com-munes, adjoining basic grid elements with the same attribute were aggregated. As a result of this procedure boundaries of communes, characterized by “step” raster structure, were obtained.
Conversion of raster to vector form of presentation was conducted through simplification and next smoothing of boundaries of thematic units. Simplification of boundaries was done with the use of Douglas-Peucker algo-rithm. In order to modify segments of boundaries in such a way, to make them running smoothly, NURBS approximation curves were applied.
Accuracy of the obtained results has been examined and scale, in which vector map can be presented, was determined.
The obtained results reveal high usefulness of the selected assumptions. Vector thematic maps can be prepared in a simple and fast way, enabling wider use of the resources stored in spatial reference grids.