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Geometric accuracy of topographical objects at Polish topographic maps

Ławniczak R., Kubiak J.

Geodesy and Cartography

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2016

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Vol. 65, no. 1

55--66

EN

The objective of research concerned verifying the accuracy of the location and shape of selected lakes presented on topographical maps from various periods, drawn up on different scales. The area of research covered lakes situated in North-Western Poland on the Międzychód-Sieraków Lakeland. An analysis was performed of vector maps available in both analogue and digital format. The scales of these studies range from 1:50 000 to 1:10 000. The source materials were current for the years 1907 through 2013. The shape and location of lakes have been verified directly by means of field measurements performed using the GPS technology with an accuracy class of RTK. An analysis was performed of the location and shape of five lakes. The analysed water regions were vectorised, and their vector images were used to determine quantitative features: the area and length of the shoreline. Information concerning the analysed lakes obtained from the maps was verified on the basis of direct field measurements performed using a GPS RTK receiver. Use was made of georeferential corrections provided by the NAVGEO service or a virtual reference station generated by the ASG EUPOS system. A compilation of cartographic and field data formed the basis for a comparison of the actual area and the length of the shoreline of the studied lakes. Cartographic analyses made it possible to single out the most reliable cartographic sources, which could be used for the purposes of hydrographical analyses. The course of shorelines shows the attached map.

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Accuracy assessment of planimetric large-scale map data for decision-making

Doskocz A.

Geodesy and Cartography

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2016

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Vol. 65, no. 1

3--12

EN

This paper presents decision-making risk estimation based on planimetric large-scale map data, which are data sets or databases which are useful for creating planimetric maps on scales of 1:5,000 or larger. The studies were conducted on four data sets of large-scale map data. Errors of map data were used for a risk assessment of decision-making about the localization of objects, e.g. for land-use planning in realization of investments. An analysis was performed for a large statistical sample set of shift vectors of control points, which were identified with the position errors of these points (errors of map data). In this paper, empirical cumulative distribution function models for decision-making risk assessment were established. The established models of the empirical cumulative distribution functions of shift vectors of control points involve polynomial equations. An evaluation of the compatibility degree of the polynomial with empirical data was stated by the convergence coefficient and by the indicator of the mean relative compatibility of model. The application of an empirical cumulative distribution function allows an estimation of the probability of the occurrence of position errors of points in a database. The estimated decision-making risk assessment is represented by the probability of the errors of points stored in the database.

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Z problematyki określenia dokładności map izopletowych

Cebrykow P.

Polski Przegląd Kartograficzny

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2004

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T. 36, nr 4

259-265

PL

W artykule opisano problemy związane z badaniem dokładności map izopletowych oraz przedstawiono źródła błędów na takich mapach.

EN

The isopleth method is rarely used as a presentation method in cartography. There are several reasons for that. One of the main causes is cartographers' distrust towards isopleths, which bases on opinions of many cartographic authorities (Eckert, Imhof, Salishchev). The main dilemma is whether it is possible to represent discontinuous phenomena with isolines. The fact that this method is highly labor-consuming also limited its popularity. Furthermore, there are no clear, acknowledged criteria for preparation of isopleth maps. In order to establish how isopleth maps should be prepared one has to determine a universal tool for their evaluation. Volumetric criterion proposed by J.Moscibroda (1999) seems to be the optimal solution. In short, it preserves unity of a statistic volume of an isopleth map with the volume of continuous choropleth. Application of a criterion of behavior of phenomenon's statistical volume helps to trace down the sources of errors, which appear on traditional isopleth maps. The research made it possible to determine three basic factors which cause errors to appear. They are: the type of basic space units, location and number of reference points and the method of interpolation. Knowing the origin of errors and being able to evaluate them on isopleth maps provides a basis for research on how to improve the methods of their elaboration.