Previously I showed you how to derive a name for yourself which would be a unique descriptor. I also showed you how to derive a unique descriptor from several birthdates, and times, including your own and at least your parents’. Now what about birthplaces. I don’t know if my brother and I were born in exactly the same geographic location, but probably close to one another. Adding the birthplaces of ancestors would help distinguish people from different families, but not siblings with identical birthplaces. My father was born in the family home at 2716 Clarke Drive, Vancouver BC, but may indeed have been born in the same bed as one of his siblings. I don’t know.
The case of twins is especially hard, since their birthplaces were likely the same down to a matter of an inch or so. Twins may be distinguished by birth times, though, and certainly by given names, so providing a total unique descriptor for any person is not a problem. But if names would suffice, and birth times good, then why look at birthplaces at all?
The answer is in the mathematical advantages of having a lot of data, more than just enough for unique descriptors. How to collect, massage and use that data is the subject of a later page. The relevance for genealogy is simple. We need to construct such descriptors for our ancestors, to the best of our ability, which we can then use in matching algorithms to provide reliable exhaustive proof of family trees.