© XY Family Tree 2012 This page explains some of the discoveries and decisions I have made whilst writing this free family history software. Trees Tall trees - from present to past (ancestors) and from past to present (descendants) OK, so you decide to explore a particular name back into the past from a certain starting person, usually yourself or maybe one of your parents. This research usually concentrates on one particular family name and traces it into the past. It becomes impossible to trace all the ancestors as they double up with every generation and you need to drop some lines because... well maybe you'll get back on that later. At least you can give this tree a family name - usually the highest, or ground level male on the male side. Tall trees are generally the most difficult to prove and seldom have any pictures with which to illustrate them. Unless you have a provable connection to an important or royal family, it's unlikely that you can have a very tall tree. Wide trees - cousins and wider relatives With a wide tree using horizontal connections, you probably have a good chance of finding your living cousins, second cousins and removed relations. As the world's population has expanded so much in the last 150 years there is a good chance that you share a common ancestor with hundreds of other living people. Spreading trees are harder to name because there are so many significant people in such trees. In a small static community a person will share common ancestors within very few generations. As people migrate into larger communities the chance of marrying a cousin is reduced, so common ancestors are only found in more distant generations. The good thing about wide trees is that they are much more likely to have pictures and other media available (subject to permission). The downside is that there are many more privacy issues. Taking cuttings - creating a new tree from an existing one XY Family Tree has a facility to make a new tree based on a selected person in an established tree. This creates a new tree as an extract from the original, that includes all ancestors of that person. It includes all descendants of those ancestors and all spouses of the ancestors. Effectively this picks up all blood relations of the selected person. Think of this like a fountain and cascade; where the water shoots as high as possible and all the cascade results from the very highest (earliest) reaches. Unconnected people In XY Family Tree you can enter people that are not connected with the actual ancestry or descendancy but who have a peripheral or interesting connection, such as the connection between Lorenzo Medici and Michelangelo. Such an association is entered in XY Family Tree as "association". This offers all sorts of possibilities to display information without bending the strict rules of biology - that a person can only have one father and one mother. The effect of errors (date, parentage) Errors of date may lead to confusion but otherwise might be simple errors. Unfortunately, date errors of any sort are very likely to lead to more serious errors, errors of parentage. Errors of parentage invalidate all relationships before that point and any connections horizontally that depend on the earlier connection. Dates are always a problem. They are a problem for at least three reasons: a date is not known at all - the field is empty and cannot be used a date is vague - "before 1920" is not a date, nor is "unknown" a date is written as text and may be formatted differently to expectation e.g. "10/11/07", could be intended to mean "2007-11-10", "1907-11-10", "10/11/1807", "11 Oct 1707", "10 Nov 1607". XY Family Tree allows you to choose dates with the year (as 4 digits) on the left or on the right. Only the year part is published on the website; this is for simplicity. All time-line views are based on a year - so you need to be consistent in your use of dates. Privacy XY Family Tree allows several levels of privacy. For individuals who are, or might be, still alive, forename can be hidden, family name can be hidden and dates can be hidden. Additionally, on the website, there are a three settings of privacy for your tree; ranging from total visibility to access only by password. Media and other interesting documents Many genealogists gather photographs, audiotape, film and video recordings of recent ancestors. The earliest photos are unlikely to pre-date 1850, film and moving images unlikely before 1920 and audiotape unlikely before 1940. So, if your family tree goes back before 1850, and many trees go back way further than then, the use of photos and media clips is of little relevance. Media is more use in a spreading tree where the majority of connections are horizontal. Of course there is always the possibility of a picture of a painting, but few paintings were made for most of us. Other interesting documents could be certificates. Certificates could go back way before media evidence but can only be displayed on a website as pictures of certificates. I read many interesting articles on how family tree programs should handle media items and have attempted to implement these on the PC. Your best and most interesting views of your recent ancestors are handled well on a PC. The website view of your family tree is more simple but can nonetheless use media files. Charts - exclusion, honesty, emphasis A chart that is intended to show a particular emphasis on a certain person or branch of a family tree must deliberately exclude information that would be important in a different chart. Because XY Family Tree has been designed as a simple and honest way to display charts of ancestors, descendants and family connections, it has no facility to emphasise particular people other than person in the focus. It does, however, have the facility to extract a branch for a chosen individual into a new file that can be displayed in the various standard ways. The extract is like a fountain; it selects all ancestors of a person as far back as they go (shoots the water as high as it can) and then all the descendants of all of these people (the cascade). Numbering systems Before computers there were many attempts at making numbering systems that were intended to simplify the connection between people, so that relationships could be deduced if you knew how the system worked. I believe that numbering systems are now obsolete as computers can calculate relationships by using their own internal logic. Humans therefore, have no need to assign numbers using any other system. See this link if you are in any doubt: http://www.saintclair.org/numbers/numlastw.html The Two Fundamental Truths  of Genealogy 1 Each Individual has a single Father and a single Mother 2 The Father and Mother may, or may not, have been connected in a “Formal” relationship The Biggest Problems with The Truths: The recorded Father and Mother might not be the biological Father and Mother; Any wrong connection invalidates all dependent information. Data Structure XY uses a logical data structure. It does not assume that children come from a family unit - it knows that children are the result of intercourse and have just two parents, whether married or not. In database parlance the XY data structure is “normalised”. There are just five tables: about people, about marriages, about associations (interesting but without the formality of marriage), about photos and other media, about linking people to photos and other media. It does not expect that the whole of your family research should be available in a single, inflexible file. Instead, XY uses normal PC files that can be kept together in folders and zipped for easy storage or transmission. The five tables are all that are needed. Moreover, the data in each table does not expect or require detailed knowledge. I could never understand why you’d need to have fields for “place of death” (unless you’re doing some research on dangerous places), “bar mitzvah” (most people wouldn’t know what that is, exactly), “social security number” (useful for use by criminals), etc. Using the simple data structure of XY Family Tree you can record all you need. It is future-proof. Sharing your data XY can be shared as information in plain files or in zipped files. The program and the data are all contained under a single main folder. As mentioned elsewhere, it’s a feature of XY Family Tree that it can run on any modern PC directly from a USB key or CD. For more blog stuff see the blog at newsway.co.uk