Geodetski list, Vol. 71 (94) No. 1, 2017.
Original scientific paper
Two Approaches to Assessing the Planimetric Accuracy of Old Maps
Martina Triplat Horvat
orcid.org/0000-0002-8304-7474
; Faculty of Geodesy, University of Zagreb, Zagreb, Croatia
Marina Viličić
orcid.org/0000-0003-4312-4073
; Faculty of Geodesy, University of Zagreb, Zagreb, Croatia
Abstract
This paper describes two methods for assessing the planimetric accuracy of old maps, by comparing the positional errors of sets of identical points located on one old and one contemporary map. The first method compares the geographical coordinates of the control points depicted on the map with their contemporary geographical coordinates mapped, in this case, in the plane of the normal aspect, equidistant conic map projection. To apply this method, the projection parameters in which the map was made must be known. In the second method, the bidimensional regression analysis proposed by Tobler was used for the geographical coordinates and coordinates of identical points in a plane of the normal aspect, equidistant conic projection. The bidimensional regression analysis method applied is based on Helmert’s transformation (according to Tobler, known as the Euclidian method) of identical points from one coordinate system to another, for example, the coordinate system of a contemporary map to the coordinate system of an old map. The deviations obtained by applying both methods are analyzed statistically and visualized. The methods were applied to produce a planimetric accuracy assessment of the Nuova carta geografica dello Stato Ecclesiastico, because this aspect has not yet been studied.
Keywords
planimetric accuracy; comparison of coordinates; bidimensional regression analysis
Hrčak ID:
181950
URI
Publication date:
27.3.2017.
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