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Land surveyors specialise in measuring and studying the shape and size of the planet Earth. They are responsible for providing an accurate display of Earth’s surface on maps and plans. Because the Earth rotates on its axis, it is somewhat oval in shape. Mathematically, it is closer to a spheroid (rotational ellipsoid), a body obtained by rotating an ellipse about its minor axis, than to a ball (sphere). Points of the Earth’s surface are projected onto the surface of a rotational ellipsoid and then transferred onto a flat surface to create a map or a plan. Due to the uneven mass density within the Earth and on its surface, the shape of Earth is even more deformed. In physics, the Earth’s shape is thus described by a geoid, which is a shape that coincides with mean sea level and extends through the continents. Elevation is measured from this surface upwards.

As part of its collaboration with international organisations, the Surveying and Mapping Authority also contributes to studying the shape and size of the Earth, its dynamics (rotation and tectonics) and gravitational field. However, it mainly gathers spatial data on the natural and built environment, and the land cover in Slovenia. Land surveyors determine the geographic position (coordinates) of land cover and natural environment – the geolocation. Moreover, the Surveying and Mapping Authority provides options for navigation – for the optimal and safe travel between chosen locations – on land, at sea and in the air. The prerequisite for precise and accurate positioning and navigation is a high-quality geodetic basis.

National coordinate system

The Surveying and Mapping Authority established and now maintains a national spatial coordinate system in compliance with international standards. The spatial coordinate system covers horizontal and vertical components. It is determined mathematically, while in fact, it is established by determining the coordinates on a stabilised geodetic grid of points with which the theoretically defined coordinate system is attached directly to the planet Earth. The vertical component is determined similarly – the mean sea level, which is the starting point of the national height system, is determined by observing the tides at tide gauges over several years. Land surveyors also determined the national map projection that is used for the transition from the curved surface of Earth to the national plane coordinate system. This system is used on maps and plans and, of course, in spatial records, i.e. in geo-referenced spatial databases.

National topographic system

The Surveying and Mapping Authority keeps a database of topographic data and different scale maps for national and local needs. Aerial photographic images, which have been cyclically taken every three years since 1975 to provide updated land cover data, serve as a basis for maintaining the database. An orthophoto, which is a photograph converted from a central projection into an orthogonal projection, is the most used product of cyclical aerial photography. It allows for cartographic display of aerial photographs, which can be used for measuring and as a foundation for other layers.

National border

The border of the Republic of Slovenia with neighboring countries is determined by border points, which we keep and maintain in the state border records. Most border points on the state border with Italy, Austria and Hungary are also marked on the ground with various border signs, border points are described in the border documentation. Data on the course of the state border are used primarily for the graphic presentation of the state border, for the harmonization of data from the land cadastre and the register of spatial units with the state border.

Register of geographical names

Geographical names are of great importance for the proper understanding of maps. The Surveying and Mapping Authority is responsible for the proper placement and grammatical correctness of names. The correct spellings of geographical names are available in the Slovenian Orthography and the Toponymic Guidelines for Slovenia. The Surveying and Mapping Authority also collaborates with the Commission for the Standardisation of Geographical Names, established by the Government of the Republic of Slovenia.