plot_gg: Plot genealogical tree with 'ggenealogy'

In maths.genealogy: Mathematics PhD Genealogy Data and Plotting

Plot genealogical tree with ggenealogy

Description

Plots a genealogical tree using the ggenealogy layout engine.

Usage

plot_gg(g, max_anc = 3L, max_des = 3L, id = NULL, col = "red", expand = 0.15)

Arguments

g	an object of class genealogy, as returned by get_genealogy().
max_anc	an integer(1) with the maximum number of generations of ancestors to be displayed.
max_des	an integer(1) with the maximum number of generations of descendants to be displayed.
id	an integer(1) or character(1) with the mathematician ID to highlight and centre the tree on. By default this is NULL which will use the first ID that was supplied to get_genealogy() when retrieving the genealogical tree. Note that the ID must be one of the IDs searched when calling get_genealogy() to construct g, since the search for ancestors/descendants only goes directly up/down branches reachable from the initial search ID.
col	a character(1) specifying the colour to highlight the mathematician one whom the graph is centred.
expand	a numeric(1) with the expansion factor for the graph. This defaults to 0.15, with larger values causing the x axis to expand, smaller values for it to shrink. This is useful if the nearest common ancestor has a long name, which may cause it to be clipped when plotting: increase this expansion factor to rectify this.

Details

This function requires the ggenealogy package to be installed. It is only a "Suggests" dependency because this package supports multiple plotting approaches. The presence of this package will be verified when the function is actually called, providing an opportunity to install automatically if needed.

This function is not suitable for plotting very large whole genealogical trees. Consider using plot_grviz() if you want to see an entire tree.

Value

An object of class ⁠("gg", "ggplot")⁠ which can be displayed, or further manipulated using additional layers or aesthetic modifications from the ggplot2 package.

References

Rutter, L., VanderPlas, S., Cook, D. and Graham, M.A. (2019). “ggenealogy: An R Package for Visualizing Genealogical Data”, Journal of Statistical Software, 89(13), 1-31. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.18637/jss.v089.i13")}.

Wickham, H. (2016). ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag New York.

Examples

# First, you need to use search_id() to find the mathematician ID for the
# individual(s) you wish to plot, or visit https://mathgenealogy.org/ to look
# up in the browser.

# For example, the package author would get their own tree using
g <- get_genealogy(171971)

# Then use the plot_gg() function to use the underlying ggenealogy package
plot_gg(g)

maths.genealogy documentation built on Aug. 8, 2025, 7:33 p.m.