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1

Kompleksowa ocena dokładności wielkoskalowych opracowań cyfrowych miasta Zielona Góra

Dąbrowski W., Doskocz A.

Roczniki Geomatyki

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2006

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T. 4, z. 3

81-93

EN

The paper presents the results of a project carried out over the last seven years by the Department of Geodesy and Property Management, Municipal Office of the City of Zielona Góra, in cooperation with the Faculty of Geodesy and Land Management, University of Warmia and Mazury in Olsztyn. The main goal of the project was to modernize the system of national geodetic and cartographic resources of the city of Zielona Góra, and to ensure its adequate quality. A restorable control network of the 3rd class was established in Zielona Góra during the years 1998 to 1999. Points of the existing horizontal geodetic control network of class I and II were incorporated into the newly-established geodetic network by classical surveys and GPS satellite technique. A total of 480 points of the existing horizontal control network of the 3rd class were adapted for this purpose. The modernization of the horizontal geodetic control network provided an accurate and reliable basis for conducting geodetic surveys and for performing cartographic work. The maximum error of position of a point within the restorable control network of the 3rd class, established in the city of Zielona Góra, is mp = 0,027 m. The accuracy of a large-scale digital map of the city of Zielona Góra, compiled based on the results of planimetric surveys conducted during the years 1974 to 1999, was estimated in 1999. The study was performed on seven control objects, using a total of 1619 control points of the following type: corner points of building contours (denoted by the letter B), boundary points of parcels (denoted by the letter G) and points of technical utilities (denoted by the letter U). The model coordinates of control points were determined based on new field surveys (with the use of an electronic tachometer - total station survey), including redundant data, which permitted to adjust the results of control measurements and to estimate their accuracy. It was found that the adaptation of the results of previous direct measurements based on an accurate geodetic control network enabled to compile a large-scale digital map with an accuracy of 0.10 to 0.20 m (i.e. at the accuracy level of previous planimetric surveys). The accuracy of a digital orthophotomap of the city of Zielona Góra, on a scale of 1:2000, was estimated during the years 2005 to 2006. The analysis was made based on 33 orthophotomap sheets in raster form (.tif files) with reference files (.tfw). A set of plane coordinates of 501 control points, determined by direct field measurements with an electronic tachometer, was used in the study. Detail control points, most of them belonging to the 1st accuracy group (i.e. the so-called .well defined points.), were considered. The points were easy to identify on the raster image of the orthophotomap, and available for precise positioning by manual vectorization. The error of position of the control points obtained by vectorization (on the raster image of the orthophotomap) was. This indicated the possibility to perform point planimetric surveys, using the raster image of the orthophotomap, with a high accuracy. With respect to considered detail points, a scale of 1:1000 can be used for the purpose of graphic representation of vector map data produced by manual vectorization. The results show that a digital orthophotomap of the city of Zielona Góra became a valuable supplement of a large-scale digital map as for the content of a cadastral map and a basis map. Both as an autonomous source of information or combined with the content of other digital maps, the orthophotomap on a scale of 1:2000 can provide the basis for studies and projects carried out within the framework of municipal GIS.

2

The use of statistical analysis for estimation of positional accuracy of large-scale digital maps

Doskocz A.

Geodezja i Kartografia

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2005

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Vol. 54, no 3

131-150

EN

The paper presents estimation of positional accuracy of digital maps using statistical analysis. Investigations have been performed for four large-scale digital maps made using different methods of producing digital map data: new total station survey (object A), re-calculation of previous direct measurements (orthogonal and polar surveys) (object B0, manual vectorisation of a raster orthophotomap image (object C) and graphical-and-digital processing of analogue maps (object D). Analysis has been performed for large statistical samples of sets of vectors of shift [...] of control points and their components, i.e. true errors [...] of increments of co-ordinates. In the case of a map produced by means of new survey with an electronic tachometer, the true errors were represented by differences between co-ordinates of control points obtained from two separate set outs. In the case of other methods of data collection for digital map production true errors were represented by differences of co-ordinates acquired from an investigated map and co-ordinates calculated from new direct surveys.

PL

W pracy przedstawiono ocenę dokładności opracowania sytuacyjnego map numerycznych poprzez analizę statystyczną. Badania zrealizowano na przykładzie czterech wielkoskalowych map numerycznych wykonanych w oparciu oróżne metody pozyskiwania danych numerycznych: nowy pomiar tachimetrem elektronicznym (obiekt A), przeliczenie wyników wcześniejszych pomiarów bezpośrednich (ortogonalnych i biegunowych) (obiekt B), manualną wektoryzację rastrowego obrazu ortofotomapy (obiekt C) oraz przetworzenie graficzno-numeryczne map analogowych (obiekt D). Analizę wykonano na dużych próbach statystycznych zbiorów długości wektorów przesunięcia punktów kontrolnych [...] oraz jego składowych, tj. błędach prawdziwych przyrostów współrzędnych [...]. W przypadku mapy wykonanej z nowych pomiarów tachimetrem elektronicznym jako błędy prawdziwe przyjęto różnice dwukrotnie wyznaczonych współrzędnych punktów kontrolnych. Natomiast w odniesieniu do pozostałych metod pozyskiwania danych do tworzenia map numerycznych, błędy prawdziwe uzyskano z różnic współrzędnych pozyskanych z badanej mapy i współrzędnych wyznaczonych z nowego pomiaru bezpośredniego.

3

Błędy szacowania parametrów w adaptacyjnych systemach z równoległym modelem odniesienia

Andrzejewski A.

Przegląd Elektrotechniczny

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2003

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R. 79, nr 9(1)

566-570

PL

Przedmiotem zainteresowania były błędy ustalone w oszacowaniu parametrów wynikające ze stosowania przybliżonych metod numerycznych służących do modelowania. Zademonstrowano wpływ niewielkich różnic, pomiędzy odpowiedzią obiektu o działaniu ciągłym a odpowiedzią modelu dyskretnego na duże błędy w wartościach oszacowanych parametrów. Przedstawiono, w jaki sposób zmieniają się parametry modelu dyskretnego przy wzroście częstotliwości sygnału pobudzającego w sytuacji, gdy parametry obiektu pozostają niezmienne.

EN

The steady-state errors of parameter estimation resulting from approximated numerical method were the object of interesting. The dependence of the high error of estimated parameters on the small differences between the continuous object response and the discrete model response was described. The frequency characteristics of the estimated parameters were placed in this paper in case of the stationary system.