2010-05-11 Extended Fan Chart
fan chart
advantages
The fan chart is my favourite chart type. It is provides an easy to understand compact overview of ancestors. A fan chart emphasizes the more recent generations, so one glance at a fan chart tells you what the most important hole in your research. Last but not least, when done right, a fan chart is aesthetically pleasing.
shortcomings
slanted
The fan chart is not perfect. One shortcoming of the typical half-circle fan chart is that the direct male and direct female lines are the only ones with near-horizontally printed text, while the text in most lines is printed at a quite noticeable angle, which does not make it easier to read the text.
size
Another characteristic of the fan chart is that the size of the box available for text depends on the generation. That recent generations have large boxes is not really a problem; the extra space can be used to print the name with larger type or perhaps show a photo; either choice makes it easier to recognise and distinguish the fan chart from other fan charts.
The real problem is that the boxes available for earlier generations are progressively smaller, making it necessary to use small type for the text. Within an application this can be solved by allowing the user to zoom, but when printed, the only solution is to make sure the text is legible by printing at sufficient size and resolution.
maximum generations
Thus, for any given paper size, there is a practical maximum to the number of
generations in a fan chart.
Legacy Charting 7, winner of the GeneAward for Best New Genealogy Product of
2008, does not just support various chart types, including fan charts, but
even supports several fan chart variants.
Legacy Charting fan chart layout variations include a Full Disc, a Half Disc, a Quarter Disc and a Split Disc (two Quarter Disks arranged like a bow tie).
A4 sheet
For all of these fan chart variations, the maximum that Legacy Charting will fit onto a single sheet of A4 is just three generations, except for the Quarter Disc layout; if you opt for the Quarter Disc layout, Legacy Charting will display as much as six generations on a single A4 sheet.
A3 sheet
As soon as you opt to display another generation, Legacy Charting will
demand an A3 sheet, and the on-screen display shows how Legacy Charting will
print the chart on two A4 sheets by highlighting the page boundary with a dashed red
line.
The maximum number of generations that Legacy Charting will fit on an A3 sheet
is 5 for the Full disc, 6 for the Half disc, as much as 9 for the Quarter Disc,
and 5 for a Split Disc configuration.
landscape mode
The numbers and images so far are for an A4 sheet in portrait mode. Legacy Charting switched the chart from portrait to landscape to landscape mode when I decided to print on A3, but that is only because because two portrait mode A4 equals one landscape mode A3.
It is an odd limitation of Legacy Charting that it can print in both portrait and landscape mode, but will only let you work with your printer's current configuration. Legacy Charting does not automatically switch to landscape mode when you opt for displaying a fan chart using the Half Disc or Split Disc layout, despite the fact that landscape mode is quite obviously the best option for these layouts. The current version of Legacy Charting simply uses the current paper size in its currents orientation.
For both the Half Disc and Split Disc layout, Legacy Charting will fit only 3 generations on an A4 in portrait mode, but in landscape mode, Legacy Charting will fit five generations into the Half Disc layout and four generations into the Split Disc layout.
Five Generation Fan Chart
Legacy will fit a five-generation fan chart on a single A4.
A five-generation fan chart can show 25-1 = 31 individuals. The
names in the fan chart shown above illustrate this explicitly.
The examples in this article use my AhnenNumbers database, a manually crafted
eight-generation database of 255 individuals in which each
individual's name is their ahnen number in English. This way, each box in
the diagram contains its own ahnen number, thus explicitly showing which part of
the ancestry are supported by a particular layout.
This Legacy Charting diagram shows a five-generation fan chart in Half Disc
layout, and that is obviously the maximum number of generations for that layout;
a six-generation fan chart would overflow the page borders.
However, although the page will not hold more complete generations,
it will easily hold more ancestors than just the last five generations.
The trick is to use an extended fan chart.
Extended Five Generation Fan Chart
An extended fan chart is a regular fan chart extended with additional boxes.
The extended five-generation fan chart holds individuals from seven generations, that is two generations more. For larger fan charts with more generations, the number of individuals and the number of additional generations that can be shown is even more. The larger the fan chart, the bigger the difference between the fan chart and the extended fan chart.
For a Half Disc layout in landscape mode, the difference is significant already, but the difference is even more pronounced for a Half Disc layout in portrait mode.
conclusion
The idea of extending a perfect fan chart to accommodate a few more
individuals, so that for example a partial seven-generation fan chart fits on
the same paper size that would otherwise hold no more than five generations
seems a fairly obvious one to me.
This article has shown examples of extending a fan chart in Half Disc layout,
but other layouts may be extended as well. The additional ancestors that can be
displayed on an extended fan chart are different for each layout.
Choosing the right chart layout and paper orientation may be enough to fit an
ancestry that otherwise would not fit.
This idea seems obvious to me, yet the genealogy charting software support
nothing but perfect fan charts, thus ignoring a lot of usable space.
A perfect fan chart is aesthetically pleasing, but for most genealogist, the
ability to include that one particular ancestral line that completes their
ancestral overview trumps aesthetic considerations.
I encourage software developers to make the best possible use of the available
space, by providing support for extended fan charts in their charting
applications.
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