Hi Luan,
in this window you are assigned tables to particular variables.
When defining the table itself you are applying ordinate values (the variation of the dimensions) to respective values on the abscissa (describing the positions throughout the segment).
So when assigning a table to a variable in a segment you need to tell the program what is the reference of the values you have used on the abscissa of the table, i.e.:
sg: station global
sl: station local
sg: segment points
The "global station" values take the value of the "starting station" (as defined when generating the axis) as the origin. All table values need to refer to this so defined axis values.
Not necessarily the segment must exactly start at the starting station of the axis (but the begin of the segment can be somewhere after that point) and even if it is the same point, there might be assigned some value for the starting station of the axis (different from zero). So the position where the segment starts defines the starting point of the "local station" and is always taken as "zero". So all table values must refer to this so defined axis values.
Finally you can also refer to the segment point numbers of the segment (as defined in the segment list) for referring the table values to instead of using station values.