A Segment-ology TIDBIT
Start with a list of your overlapping shared segments – they all match you (two triangle legs). Find two of these shared segments that match each other (third triangle leg) to form a Triangulated Group! All the rest of the shared segments in your overlapping segment list need only match one of the shared segments in the TG – any one of them with a good overlap – to be added to the TG. The explanation will take a long blog post with diagrams – but the thrust is that forming a TG basically identifies that segment just as good as trio-phasing. So trust me! If a shared segment doesn’t match the TG, it will match the other, overlapping TG; or it is IBC (it happens for some shared segments under 15cM). As a Quality Control measure, I often make a second comparison – it always matches!
[22D] Segment-ology: Only One Comparison Needed to Add a Segment to a TG TIDBIT by Jim Bartlett 20170101