Each polyline will be represented by the position of the connection points and the connectivity information. The output file will contain four columns:
1. X-coordinate
2. Y-coordinate
3. Z-level
4. Connectivity information (1: connected to next point, 0: end of line)
If the feature data contains a z-value (type PolylineZ), this value is written to the third column, otherwise the third column contains 0.
If a optional z-field has been chosen, the z-value is derived from this.