These consisted of a wooden post, at the upper end of which were direction indicators in the shape of human arms and hands. Because the wood rotted rapidly as a result of its constant exposure to moisture, many of these fingerposts collapsed a few years after they had been erected and became unusable. The establishment of postal mileposts in electoral Saxony was not an isolated phenomenon. Similar posts or stones with distances marked on them were erected along the roads in a number of countries. The basis for the introduction of Saxon mileposts was the cartographic work of the pastor, Adam Friedrich Zürner, from Skassa. Zürner had prepared a map of Großenhain, which attracted the attention of Augustus the Strong. After further cartographic work, the prince elector gave him the task on 12 April 1713 of: "recording districts, including the lordships, manor estates, towns, villages and the like, on geographic maps" (original: ""Aemter samt denen darinnen befindlichen Herrschaften, Rittergütern, Städten, Dörfern und dergleichen mehr in mappas geographicas bringen"). This entailed the topographic survey of Electoral Saxony. In addition to the heartland, it covered the electoral Saxon parts of the counties of Henneberg and Mansfeld, the Schönburg estates, the estates of the Albertine branches of Saxe-Merseburg, Saxe-Weissenfels and Saxe-Zeitz as well as the two Lusatias. The resulting cartographic material remained largely secret for several decades for military reasons. The prince elector only had an improved postal map published which was the result of an extension to the contract that followed a few weeks later. This ""Chur-Sächsische Post-Charte", first published in 1718, and its subsequent editions, remained in use until the 19th century. Because the distances stated at that time were frequently based on imprecise estimates, Zürner had to survey the distances afresh or verify existing data. To achieve that he designed a survey vehicle in the shape of an electoral Saxon baggage coach. Each revolution of the rear wheel of the coach with a circumference of one Dresden rod ("Dresdner Rute"), i.e. 4.531 metres, was transmitted to a mechanical counter in the coach by means of a chain. Zürner's assistants used a measuring cart in the shape of a wheelbarrow for those tracks unsuitable for a coach, which likewise measured the distances by the turning of a wheel and which was carried as the so-called "fifth wheel on the wagon" ("fünftes Rad am Wagen") in a case on the surveying coach.