ELETTRA is an intermediate energy Synchrotron Light Source located in the outskirts of Trieste, Italy, open to researchers of basic and applied fields such as material and life sciences, physics, chemistry and geology. The synchrotron is operated 24 hours/day, 7 days/week with few periods of shutdown, mostly dedicated to maintenance. During one of these periods, in August 2001, ENEA Fusion Technology Division (Italy), in collaboration with ELETTRA Accelerator Sector and Paul Scherrer Institut (PSI, Switzerland), carried out the 3D dimensional survey of the storage ring using its own optical metrology system (Leica laser tracker LTD500). The aim of the survey was re-alignment of the storage ring magnets of the synchrotron. Within a two-weeks time shutdown, more than 2300 single measurements were taken on the 24 bending magnets, 108 quadrupoles and 72 sextupoles placed in the 259.2 m circumference storage ring. The overall root mean square error of the oriented network were less than 0.1 mm, thus making possible a subsequent and successful one-week alignment of one fourth of the storage ring (October 2001). This performance completely fulfilled the very demanding survey specifications in terms of accuracy, time required, and usability of the measurements. This paper illustrates the survey, the method and the instrumentation adopted and the results obtained. Moreover, it gives guidelines to be taken into account when planning the alignment of accelerators or large and heavy components.