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The results of measuring elevations leveling using an optical beam straightness, contain, besides the desired constant height, variable part caused by the influence of refraction. The latter has traditionally been seen as an error (random and partly systematic). However, these “errors” due to physical causes, are not subject to statistical regularities, but because they can not provide a mean-square error. Fluctuations in the heights under the influence of refraction caused by physical laws, which makes use of classical methods to evaluate the accuracy and altitude adjustment flawed.

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Sequence of neural networks has been applied to high accuracy regression in 3D as data representation in form  z = f(x,y). The first term of this series of networks estimates the values of the dependent variable as it is usual, while the second term estimates the error of the first network, the third term estimates the error of the second network and so on. Assuming that the relative error of every network in this sequence is less than 100 %, the sum of the estimated values converges to the values to be estimated, therefore the estimation error can be reduced very significantly and effectively. To illustrate this method the geoid of Hungary was estimated via RBF type network. The computations were carried out with the symbolic - numeric integrated system Mathematica.

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Preliminary attempts to georeference maps of early twentieth century made by the Military Geographic Institute (IGM, the Italian geodetic agency) for the city of Rome and its surroundings, reported residual errors larger than errors observed on similar maps. Previous studies carried out on one or two century older maps of the same area, showed similar or even smaller errors (Baiocchi and Lelo 2005).Six sheets of the “City of Rome and its surroundings” map in scale 1:5 000 dated 1908 have been studied. The identified errors can be referred to the different system of geodetic projection and geodetic datum or to the derivation of some details from maps at smaller scale, but in this case historic documents seem to suggest a different explanation.Parameters useful to perform the transformation of the geodetic systems used in historical maps to modern systems are not known; for this reason until now the various attempts of georeferencing maps of this type were based on collimation of points recognizable on modern cartographies such as corners of historical buildings. This method has often given unsatisfactory results; therefore it was decided to proceed by determining the parameters for the transformation of geodetic datum.The history of geodetic systems used in Italy at the beginning of the 20th century is complex and, in the past, this has led some researcher to misinterpretations. For this reason a full explanation of geodetic systems used in Italy in this period is reported below. Since the parameters of the projection used for the maps in our case study are not known for sure, the reprojection was considered the only way for a correct georeferencing.

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are fuzzified to extract the land-use classes (Appendices  1 and 2 ), after which both LSMA and MLC results undergo a classification accuracy assessment, which must be greater than 80% for the classification to be used; Step III: The green vegetation

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Brookins, D. 1988: Eh-pH diagrams for geochemistry. - Springer-Verlag, Berlin. Erikson, L., R.E. Werner, M. Westdahl 1992: An improved version of the trial and error indexing program TREOR. Accuracy and Powder Diffraction II

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the Babakoohi Anticline, based on the clustering indices. The graph also displays the overlapping and outlier data. In the fuzzy K-means clustering method, the accuracy of the number of clusters is determined by the fuzzy algorithms validation indices

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the Babakoohi Anticline, based on the clustering indices. The graph also displays the overlapping and outlier data. In the fuzzy K-means clustering method, the accuracy of the number of clusters is determined by the fuzzy algorithms validation indices

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References M. Al-Husseini 2007 Revised ages (Ma) and accuracy of Arabian Plate maximum flooding surfaces GeoArabia

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M.J. Spicuzza 1995 UWG-2, a garnet standard for oxygen isotope ratios: Strategies for high precision and accuracy with laser heating Geochimica et Cosmochimica Acta

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WQ samples in cluster Number of WQ samples per WB Mean intra-group distance Prediction accuracy of model 1 [%] Prediction accuracy of model 2 [%] 1 40 3044 76 3.0 68 85 2 42 2867 68 4.0 69 74 3 19 1492 79 4.7 26 42 Total 101 7403 73 3.7 60 72 Figure 6

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