This file determines the initial area when the game starts and location of the screen view.
The first column is filled with th identifiers AREA, XPOS and YPOS, with entries for normal, tutorial and multiplayer game modes. AREA defines the start area, XPOS and YPOS determine the location of the screen view. The second one holds entries specifying values for the first column.
In BG2 ToB we have:

2DA V1.0
BADVAL
                        VALUE
START_AREA              AR0602
START_XPOS              3666
START_YPOS              2878
START_AREA_TUTORIAL     AR0015
START_XPOS_TUTORIAL     607
START_YPOS_TUTORIAL     660
START_AREA_MP           AR4000
START_XPOS_MP           1311
START_YPOS_MP           2347