Although a new state coordinate system (ESRS - European Spatial Reference System) has been in force since 2008 in Slovenia, it has still not been fully implemented in practice.
ETRS89/TM transverse Mercator coordinate system is based on the ellipsoid GRS 80 and used on ETRS 89 based geodetic SITRS 96 datum. In Slovenia, the WGS84 is being currently used, which is a reference ellipsoid determined in 1984. It is defined in such a way that it best fits the whole Earth, i.e. that the sum of deviations of the Earth's surface from this ellipsoid is minimal. It is used in connection with the GPS satellite navigation system.
The breeding distribution of birds and occupancy of toponyms can be presented in different ways, depending on the level of accuracy and concept. In faunistic survey, the breeding distribution of bird species is shown in the form of breeding distribution map, which was made by us with the aid of DMAP digitizer programme and georeferenced.
During our work, 100 x 100 m UTM grid was applied, which is used for the mapping of smaller areas. The UTM coordinate system is a universal system. It is also a transverse Mercator coordinate system placed over WGS84 global ellipsoid. This coordinate system is becoming a standard in EU and should be shown by every GPS receiver. The list of concrete sites obtained with the aid of GPS enables a higher level of accuracy.
The data on the breeding distribution of separate bird species that were entered into the maps prior to 2007, were converted from the Gauß-Krüger coordinate system and adjusted to the new coordinate system, with the new coordinates entered into the database.
Since 2008, PDAs equipped with suitable programme and GPS receiver, have been used during our field work. The measurements of positions with GPS have already been expressed, without additional conversions, directly in the new coordinate system. Database maintenance in the new system and with the new GPS measurements will gradually improve the position accuracy and data quality, especially with the introduction of the European Galileo system.