期刊名称：Annales Universitatis Mariae Curie-Skodowska. Sectio B, Geographia, Geologia, Mineralogia et Petrographia
印刷版ISSN：0137-2025
出版年度：2004
卷号：LIX
出版社：Maria Curie-Sklodowska University, Lublin
摘要：The first part of the article concerns scale assessment. An average value of scale results from several local scales. They, in turn, are obtained by selecting points on the early map which can be identified beyond doubt on the modern map and measuring and comparing corresponding distances on both maps.
Scale variation can be presented by means of isopleth interpolated according to values of local scales (see Fig. 1 and 2).
Analysis of distances is a very common type of examination. Two error ratios are used in most cases - relative and absolute. Absolute error is the difference between measured and real distance, while relative is the relation of the absolute error value to real distance (in percentage). Individual errors are listed and average values are calculated.
Apart from this, other methods are used: arithmetic mean, standard deviation or correlation coefficient. Map angles are examined in the way distances are. Individual errors are used to calculate Gauss average. An analysis of coordinate points is also based on Gauss formula. The result is an average error of latitude and longitude (in metres or degrees). Both can be used to calculate average location error.
An analysis of areas is reduced to, in most cases, simple comparison of measured values.
Graphic methods of examination help to visualize accuracy of early maps. The most popular one is the distortion grid. It is the grid drawn on the early map according to location of points whose real coordinates may be read from the modern map (see Fig. 3). Other methods are: showing differences between maps (Fig. 4), presenting regions of similar distortion (Fig. 5) and mentioned isopleths of scale variation.
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