This geom performs edge bundling using the edge path algorithm. This approach
uses the underlying graph structure to find shortest paths for each edge in
a graph the is gradually removed of it's edges. Since it is based on the
topology of the graph it should lead to less spurious bundling of unrelated
edges compared to geom_edge_bundle_force() and also has a simpler parameter
space.
geom_edge_bundle_path(
mapping = NULL,
data = get_edges(),
position = "identity",
arrow = NULL,
n = 100,
directed = NULL,
max_distortion = 2,
weight_fac = 2,
tension = 1,
lineend = "butt",
linejoin = "round",
linemitre = 1,
label_colour = "black",
label_alpha = 1,
label_parse = FALSE,
check_overlap = FALSE,
angle_calc = "rot",
force_flip = TRUE,
label_dodge = NULL,
label_push = NULL,
show.legend = NA,
...
)geom_edge_bundle_path2(
mapping = NULL,
data = get_edges("long"),
position = "identity",
arrow = NULL,
n = 100,
directed = NULL,
max_distortion = 2,
weight_fac = 2,
tension = 1,
lineend = "butt",
linejoin = "round",
linemitre = 1,
label_colour = "black",
label_alpha = 1,
label_parse = FALSE,
check_overlap = FALSE,
angle_calc = "rot",
force_flip = TRUE,
label_dodge = NULL,
label_push = NULL,
show.legend = NA,
...
)
geom_edge_bundle_path0(
mapping = NULL,
data = get_edges(),
position = "identity",
arrow = NULL,
directed = NULL,
max_distortion = 2,
weight_fac = 2,
tension = 1,
lineend = "butt",
show.legend = NA,
...
)
Set of aesthetic mappings created by ggplot2::aes()
or ggplot2::aes_(). By default x, y, xend, yend, group and
circular are mapped to x, y, xend, yend, edge.id and circular in the edge
data.
The return of a call to get_edges() or a data.frame
giving edges in correct format (see details for for guidance on the format).
See get_edges() for more details on edge extraction.
Position adjustment, either as a string naming the adjustment
(e.g. "jitter" to use position_jitter), or the result of a call to a
position adjustment function. Use the latter if you need to change the
settings of the adjustment.
Arrow specification, as created by grid::arrow().
The number of points to create along the path.
Logical. Should the shortest paths be calculated using
direction information of the graph. Setting this to TRUE can help split up
bundles that flows in opposite directions. Ignored for undirected graphs
A multiplication factor to determine the maximum
allowed distortion of the path during bundling. If the new edge is longer
than max_distortion times the old length it is rejected.
The exponent used to assign weights to the graph when
calculating the shortest path. The final weights are given as
edge_length ^ weight_fac meaning that sorter edges are prioritised when
calculating the weights.
A loosening factor when calculating the b-spline of the edge based on the shortest path. Will move control points closer and closer to the direct line as it approaches 0
Line end style (round, butt, square).
Line join style (round, mitre, bevel).
Line mitre limit (number greater than 1).
The colour of the edge label. If NA it will use
the colour of the edge.
The opacity of the edge label. If NA it will use
the opacity of the edge.
If TRUE, the labels will be parsed into expressions
and displayed as described in grDevices::plotmath().
If TRUE, text that overlaps previous text in the
same layer will not be plotted. check_overlap happens at draw time and in
the order of the data. Therefore data should be arranged by the label
column before calling geom_text(). Note that this argument is not
supported by geom_label().
Either 'none', 'along', or 'across'. If 'none' the label will use the angle aesthetic of the geom. If 'along' The label will be written along the edge direction. If 'across' the label will be written across the edge direction.
Logical. If angle_calc is either 'along' or 'across'
should the label be flipped if it is on it's head. Default to TRUE.
A grid::unit() giving a fixed vertical shift
to add to the label in case of angle_calc is either 'along' or 'across'
A grid::unit() giving a fixed horizontal shift
to add to the label in case of angle_calc is either 'along' or 'across'
logical. Should this layer be included in the legends?
NA, the default, includes if any aesthetics are mapped.
FALSE never includes, and TRUE always includes.
It can also be a named logical vector to finely select the aesthetics to
display.
Other arguments passed on to layer(). These are
often aesthetics, used to set an aesthetic to a fixed value, like
colour = "red" or size = 3. They may also be parameters
to the paired geom/stat.
geom_edge_force_path and geom_edge_force_path0 understand the following
aesthetics. Bold aesthetics are automatically set, but can be overwritten.
x
y
xend
yend
edge_id (should not be overwritten)
edge_colour
edge_width
edge_linetype
edge_alpha
filter
geom_edge_force_path2 understand the following aesthetics. Bold aesthetics are
automatically set, but can be overwritten.
x
y
group
edge_id (should not be overwritten)
edge_colour
edge_width
edge_linetype
edge_alpha
filter
geom_edge_force_path and geom_edge_force_path2 furthermore takes the following
aesthetics.
start_cap
end_cap
label
label_pos
label_size
angle
hjust
vjust
family
fontface
lineheight
The position along the path (not computed for the *0 version)
Many geom_edge_* layers comes in 3 flavors depending on the level of control
needed over the drawing. The default (no numeric postfix) generate a number
of points (n) along the edge and draws it as a path. Each point along
the line has a numeric value associated with it giving the position along the
path, and it is therefore possible to show the direction of the edge by
mapping to this e.g. colour = after_stat(index). The version postfixed with a
"2" uses the "long" edge format (see get_edges()) and makes it
possible to interpolate node parameter between the start and end node along
the edge. It is considerable less performant so should only be used if this
is needed. The version postfixed with a "0" draws the edge in the most
performant way, often directly using an appropriate grob from the grid
package, but does not allow for gradients along the edge.
Often it is beneficial to stop the drawing of the edge before it reaches the
node, for instance in cases where an arrow should be drawn and the arrowhead
shouldn't lay on top or below the node point. geom_edge_* and geom_edge_*2
supports this through the start_cap and end_cap aesthetics that takes a
geometry() specification and dynamically caps the termini of the
edges based on the given specifications. This means that if
end_cap = circle(1, 'cm') the edges will end at a distance of 1cm even
during resizing of the plot window.
All geom_edge_* and geom_edge_*2 have the ability to draw a
label along the edge. The reason this is not a separate geom is that in order
for the label to know the location of the edge it needs to know the edge type
etc. Labels are drawn by providing a label aesthetic. The label_pos can be
used to specify where along the edge it should be drawn by supplying a number
between 0 and 1. The label_size aesthetic can be used to control the size of
the label. Often it is needed to have the label written along the direction
of the edge, but since the actual angle is dependent on the plot dimensions
this cannot be calculated beforehand. Using the angle_calc argument allows
you to specify whether to use the supplied angle aesthetic or whether to draw
the label along or across the edge.
In order to avoid excessive typing edge aesthetic names are
automatically expanded. Because of this it is not necessary to write
edge_colour within the aes() call as colour will
automatically be renamed appropriately.
Thomas Lin Pedersen and David Schoch
Wallinger, M., Archambault, D., Auber, D., Nöllenburg, M., and Peltonen, J. (2022). Edge-Path Bundling: A Less Ambiguous Edge Bundling Approach. IEEE Transactions on Visualization and Computer Graphics 28(1) 313-323. https://doi.org/10.1109/TVCG.2021.3114795
Other geom_edge_*:
geom_edge_arc(),
geom_edge_bend(),
geom_edge_bundle_force(),
geom_edge_bundle_minimal(),
geom_edge_density(),
geom_edge_diagonal(),
geom_edge_elbow(),
geom_edge_fan(),
geom_edge_hive(),
geom_edge_link(),
geom_edge_loop(),
geom_edge_parallel(),
geom_edge_point(),
geom_edge_sf(),
geom_edge_span(),
geom_edge_tile()
ggraph(highschool) +
geom_edge_bundle_path()
# Use tension to lessen the effect
ggraph(highschool) +
geom_edge_bundle_path(tension = 0.8)
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