engleski

Study of Length Differences from Topography to Map Projection within the State Coordinate Systems for some Countries on the Balkan Peninsula

All geodetic measured quantities from the physical surface of the Earth are reduced to the geoid and surface of adopted reference ellipsoid through applying corrections on the measured values, as well projected to the map projection. Before calculating the Cartesian coordinates of points in a formal state geodetic coordinate system, the horizontal lengths between points on the topography surface first should to be reduced from the topography to the mean see level (geoid), then from the geoid to the reference ellipsoid, and after that projected from the ellipsoid into the map projection. Up to now, within the research analyses have been performed for defining of most appropriate State Plane coordinate system, the choice of most suitable national map projection is based on the requirements of accurate representation of the earth surface on the plane with minimum distortions. This choice is usually based on the research analyses performed for defining of most appropriate State Plane coordinate system. During the literature review, analyses of the length changes between points within successive projections from the earth surface to the chosen state map projection were not found. Recognition of the length differences for whole country areas mapped on the State Plane coordinate system are very important data for many geodetic and cartographic applications. This research aims to develop and provide national GIS datasets of lengths' differences on a grid with cells 1x1 km covering national territories of seven Balkan countries – Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Kosova, FYRo Macedonia and Montenegro. Assessment and comparison of successive length differences between four surfaces (from the Earth surface, through geoid and ellipsoid, to the map projection) have been realized through calculation of mean linear deformations of 1km lengths, dispersion, maximum and minimum values, as well as their positive, negative or zero values. The differences between the real length on earth surface and on a map projection due to elevation factor were evaluated, that gave an impression on the quality of state geodetic coordinate systems, of the seven analyzed countries.

state coordinate system ; state map projection ; distortion ; length differences ; topography ; geoid ; reference ellipsoid

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