Stereofotogrametrinis skaitmeninis Vilniaus žemėlapis ir jo panaudojimo ypatumai

Abstract

Since 1996, the Institute of Geodesy of the Vilnius Gediminas Technical University has worked on order of Vilnius Municipality Vilnius city's GIS basic digital map. The digital map is compiled by stereodigitalisation aerial photography at a scale of 1:6000. The georeference data basis (GDB) was created on the area of 125 sq km. Stereophotogrammetrically formed GIS basic digital map of Vilnius city is used for the municipality needs, too. Often entered from old maps at a scale of 1:500 the engineering networks and other objects, also the measurement data of parcels link badly with the stereodigitalised objects of digital map. Discrepancies are 0,5 m and more. It provokes some problems. To clear up the accuracy of the different topographical information and to facilitate the solution of problems the complex investigations of existing Vilnius plans and digitally constructed maps were compiled. It was defined by field measurements that the mean square errors of clear contours are 0,26 m - 0,34 m (maximum 1 m). The errors of checked segment lengths were 0,29 m and 0,78 m. The accuracy of DB point elevations is 0,14 m (0,15 % of flying height). Maximum discrepancy is 0,39 m [...].