This is Document of Positional System in Vice City map, many players use /s to save coords but they don't know much about x y z coords, they have hard time setting up Objects like players spawn pos or setting player pos , pickup , player requesting skin ( usually the hard part ) Vehicle stuff.
View this picture extended tab or windows, as it is in large size and may not come in forum frame.
http://psyshell.sc-mp.net/vcmpxyz.jpgexplained everything you must know. if i missed something, or you are getting messedup or not understanding it.
ask here in reply's i will be able to help. if possible.