The Ordnance survey map of 1859 and 1860 is largely based on the map of 1834 and continues the tendencies and developments towards higher standardisation and better methods that had already characterised the previous map. Building on the foundations laid by Müffling, the land survey was initially continued and the methods refined. This was followed by a complete new survey using the new methods.
The formative personalities in the further development of the Landesaufnahme were the officer Johann Jacob Baeyer (1794-1885), who had already contributed to the development of the Müffling ellipsoid, and the Königsberg professor Friedrich Wilhelm Bessel (1784-1846). They had a great influence on the technical and organisational development of topographic mapping. During their collaboration, Bessel tended to play the role of a skilful theoretician, while Baeyer had a high degree of practical experience thanks to his service on the General Staff. From 1832 onwards, Baeyer and Bessel were involved in the "Verbindungsmessung" (survey alliance) with the Russian Empire, in which the Prussian triangulation nets were connected with those of the Russian survey until 1835. The advantage of this kind of measurement is that it is possible to obtain more precise data over longer distances and thus to control and improve one's own measurements.
The connection of the Russian network and the Prussian network took place in the area of East Prussia. Memel and Königsberg, among others, were fixed points of measurement at which astronomical locations were determined. New triangulation lines were then measured between these points. Two of the intersections of this measurement are located on the Curonian Spit, one in Nidden (Nida) and the other in the lost village of Lattenwalde. Due to the temporal overlap, it is possible that the maps of 1834 are a product of this survey alliance with the Russian Tsarist Empire.
One result of this measurement was the production of more accurate maps. Furthermore, Bessel discovered that the Müffling ellipsoid deviated significantly from the real Earth's shape. He then developed his own new ellipsoid. This Bessel ellipsoid was published in 1841 and was based on a total of 10 degree measurements. From 1866, this ellipsoid became the basis for surveying in Germany and other countries for over a century.
However, the Ordnance Survey maps of 1859/1860 were created before the Bessel ellipsoid was used. Like their predecessors, they were also recorded in the Ordnance Survey sheet format 1:25,000. Compared to the Müffling maps, they are characterised by a higher level of detail and more accurate images. In addition, the hatches (oblique markings of the terrain contour based on the cast shadows) were replaced by contour lines.
Works Cited
Hamel, Jürgen; Buschmann, Ernst (1996) Friedrich Wilhelm Bessels und Johann Jacob Baeyers Zusammenwirken bei der „Ostpreußischen Gradmessung" 1830-1838. In: Seeger. Hermann (Eds.) Beiträge zum J. J. Baeyer-Symposium. Berlin-Köpenick, 05.-06. 11. 1994. Verlag des Instituts für Angewandte Geodäsie, Frankfurt am Main, pp. 45-57.
Müffling, Karl P. F. C. F. von (1821 [1980]): Instruction für die topographischen Arbeiten des Königlich Preußischen Generalstabes. Reproduktion des Instituts für Angewandte Geodäsie. 1980.
Torge, Wolfgang (2002): Müfflings geodätisches Wirken in der Umbruchepoche vom 18. zum 19. Jahrhundert. In: Zeitschrift für Vermessungswesen (ZfV) 127, pp. 97–108.
Torge, Wolfgang (2005): Der lange Weg der preußischen Landesvermessung: zum 100. Todestag von Oscar Schreiber (1829–1905). In: Zeitschrift für Vermessungswesen (ZfV) 130 (6), pp. 359–371.
Torge, Wolfgang (2009): Geschichte der Geodäsie in Deutschland. 2. ed. Berlin: de Gruyter.