[Mean]

IsPlayerInRangeOfPoint should do the work

like

pawn Код:

public OnPlayerSpawn(playerid)
{
    if(IsPlayerInRangeOfPoint(playerid, los, santos, spawn, 15)) 
    {
        SendClientMessage(playerid, COLOR, "You spawned in Los Santos");
    }
    if(IsPlayerInRangeOfPoint(playerid, san, fierro, spawn, 15))
    {
        SendClientMessage(playerid, COLOR, "You spawned in San fierro");
    }
    // And so on...
    return 1;
}

Replace these los, santos, spawn with X, Y and Z of thoose spawns, and replace the COLOR.