Although in the GROMA program, the formats for the input and output data are defined at the same time, the output format has some special features the input format does not.
If the input format is defined in the same way as the output format, it would allow loading data from any file of fixed format, i.e. from a file where relevant data is located in fixed positions on each line (i.e. the coordinate X on positions 10-22, etc.).
However, a text file doesn't generally have to meet this requirement. It can look for example like this:
8 1045656.12 740143.45 9 1045778.3 740227.66 10 1045771.13 740439.01
In this case, the data does not have a fixed position on the line and, therefore, can't be loaded in a fixed format (e.g. coordinate X start at position 3 to 4, according to the point number size).
For this reason, the so called Free format was also included in the program. This does not require data in fixed positions, but loads them according to the position of the separator characters (spaces, tabulators, and other non-numeric characters).