Segment (.seg) file format description

The file describes the branching structure of cells, allowing compartemntal models to be built from the neurons.

• Each line in the file is a record, containing data of a subsegment, a homogenous non-branching cylinder.
• The first line is the header.
• Each record consist of the following fields:
• Branch #    Segment length     Order       Segment type    Segment diameter    Segment name
• Branch#: identifies the segment.
• 1a means first subsegment of the first primary branch
• 11a first subsegment of the first secondary branch on the first primary branch
• 12a first subsegment of the second secondary branch on the first primary branch
• 12b second subsegment of the second secondary branch on the first primary branch
• the number of digits involvs the order ot the branch 
  e.g.:      11a   11b 
  1a         ------|---------       121a 
  --------<  12a       12b     --------- 
              ----------|-------< 122a     122b 
                                        ---------|-------
• subsegments were required, because a single unbranched segment might consist of different subtypes  (involving change in diameter). Subsegments of the same unbranched segment (e.g. 1122) are labelled with consequtive letters (1122a, 1122b, 1122c).
• Segment length: length of a subsegment in micrometers
• Order: order of subsegment
• Segment type: type of subsegment
• Segment diameter: diameter of the subsegment (equal for subsegments with the same type)
• Segment name: description of subsegment (equal for subsegments with the same type)