Networks / Pajek
Package for Large Network Analysis

How to
visualize genealogies with Pajek

 I would like to use Pajek for laying out an old family tree, people
 around 1530, in GEDCOM format.
 I need a special layout because there used to be a lot of 2nd, 3rd
 or 4th weddings and other "incidents".

 I have donwloaded pajek and wanted to play with it but couldn't find
 the right options to use to layout a standard GEDCOM file.
 When I download the "Oldham.ged" file for testing, Pajek recognize
 the format and generates FAMS number in the "vector" line.  From that,
 all I can do is generate a circular layout with the "draw" button
 (I need to increase the number of vertices in the option menu first.)

 Could you provide me with a simple sequence of operations I should
 perform to layout the family graph nicely?
  Jean-Daniel Fekete

Let us take the Oldham.ged as an example. Download it and read into Pajek. We shall represent the genelogy as a p-graph. For details on p-graphs see the Douglas White's P-graphs page.

Options/Read-write/Gedcom-Pgraph ON
Options/Max vertices to draw 10000
read Ged file ... using network read buttun

The network has 17804 vertices and 17661 arcs. Usually several (weakly connected) components exist in large genealogies. They can (should?) be analysed separately.

Net/Components/Weak 2

There are 153 nontrivial weak components (clusters); cluster 18 has 1117 vertices. Let's extract it and produce an initial layout using macro LAYERS.

Operations/Extract from network/Partition 18 18
Macro/Play .../pajek/macro/genea/layers.mcr
Draw/Draw partition
Layers/Optimize .../Complete

Now we can manually edit the obtained picture. Press right mouse button and select a subregion to edit. To return to the complete picture select the option Redraw.

p-graphs usually contain a lot of subtrees. The interesting cases (marriages between relatives) are in the biconnected parts - you can identify them using


or, simply by removing the subtrees by

Net/Transform/Reduction/Degree/All 2 Yes

We get a network on 840 vertices. Again there can be several components.

Net/Components/Weak 2


How to?; Pajek; Vlado/Networks