Since 1996, the Department of Archaeology of the University of Ljubljana has been applying GPS technology for archaeological surveying, in collaboration with 2B Geoinformatics company. Two issues will be discussed here. The first is about precision measurements in archaeological survey of landscape structures pertaining to ancient regular land divisions. In 1996, GPS was used to survey the chora of the 4th c. B.C. Greek colony of Pharos on the island of Hvar, Croatia. Precision measurements were taken of disconnected surface structures which were identified, based on previous analysis using the 1:5000 maps, as key points for the analysis of the organization of the ancient land division. Surveying with classical instruments and with total station was out of question there, since an area of 6 km2 was to be covered, and the visibility between the points to be surveyed was difficult to achieve. The precision of the measurements was calculated at under 1 cm, and that permitted to identify error in ancient surveying, and to propose a reconstruction of the surveying procedure, including the location of the omphalos, the starting point of the measurement by ancient surveyors. The other issue concerns archaeological excavation, where GPS was used parallel to total station to test the pros and contras of its systemic use in stratigraphic dig, and notably in documenting surfaces of stratigraphic units for DMR.