Analysis of the latitudinal data of Eratosthenes and Hipparchus
  The handed down latitudinal data ascribed to Eratosthenes and Hipparchus are composed and each tested for consistency by means of adjustment theory. For detected inconsistencies new explanations are given concerning the origin of the data. Several inconsistent data can be ascribed to Strabo. Differences in Hipparchus' data can often be explained by the different types and precision of the data. Gross errors in Eratosthenes' data are explained by their origination from the lengths of sea routes. From Eratosthenes' data concerning Thule a numerical value for Eratosthenes' obliquity of the ecliptic is deduced. 
Christian Marx
physics.hist-ph