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Plot the global trajectories as 2D variable-width lines

Source: R/plot_trajectory_lines_2d.R
plot_trajectory_lines_2d.Rd

The line counterpart of plot_trajectory_confluence() over the global flow DAG. Every global trajectory is drawn as a variable-width line through the year-aware Sugiyama layout: the central finals tr::cNgN and the intermediate trN that feed them, each line widening with the documents accumulated along its path. A bottom legend reports, for every intermediate, how many papers of its terminal cohort reached each final group – a single trN can feed more than one final (its terminal cohort splits across groups), which the legend makes explicit.

Usage

plot_trajectory_lines_2d(
  flow,
  target = "all",
  conf = NULL,
  min_n = 5,
  min_prop = 0.05,
  min_total_size = 0,
  min_duration_years = 0,
  min_target_n = 0,
  width_range = c(0.8, 6),
  use_raw_papers = FALSE,
  label_size = 4,
  dest_min_prop = 0.05,
  lowlight_alpha = 0.18,
  lowlight_color = "#9AA5B1",
  legend_ncol = NULL,
  legend_text_size = NULL,
  axis_text_size = NULL,
  year_range = NULL,
  palette = NULL,
  title = NULL
)

Arguments

flow

A sniff_trajectory_braid() object, or a docs_per_group tibble / sniff_trajectory_dag() object the flow is built from.

target

What to draw. "all" (default) draws every central and the trajectories feeding it; a central traj_id (e.g. "tr::c1g1") or a vector of them draws only those finals and their feeders.

conf

An optional precomputed sniff_trajectory_confluence() object for flow; pass it to skip recomputing the confluence on every call (e.g. in a Shiny app that re-renders as a selector changes). NULL (default) computes it.

min_n, min_prop, min_total_size, min_duration_years

Feeder thresholds, passed to the same pruning used by plot_trajectory_confluence(): an intermediate is drawn only if it transfers >= min_n papers and >= min_prop of its cohort, has total size >= min_total_size and lifespan >= min_duration_years; a pruned intermediate takes its own feeders with it.

min_target_n

Minimum papers an intermediate must leave in the selected final(s) by the last year to be drawn (default 0, no filter). Unlike min_n (the tree-edge transfer to its absorber), this counts the intermediate's own papers that end up in the target group, so a feeder that merges in but barely persists there (e.g. tr39 with 12 of its papers in c1g1) is dropped by min_target_n = 20. Only applies to a targeted final view.

width_range

Line-width range c(min, max) (default c(0.8, 6)), scaled by the cumulative tracked documents along each trajectory.

use_raw_papers

Scale widths by raw quantity_papers (TRUE) or by the weighted quantity_papers * prop_tracked_intra_group (FALSE, default).

label_size

Text size of the trN / tr::cNgN end labels (default 4).

dest_min_prop

In the target = "all" view only, the minimum share of an intermediate's terminal cohort that must reach a final for that final to appear in its legend entry (default 0.05). A targeted view reports only the selected final(s), so this does not apply.

lowlight_alpha, lowlight_color

Opacity and colour of the background (non-trajectory) edges (defaults 0.18, neutral grey).

legend_ncol

Number of columns in the feeding legend; NULL (default) lets ggplot choose.

legend_text_size

Font size (pt) of the legend text; NULL (default) keeps the theme default.

axis_text_size

Font size (pt) of the x-axis (year) tick labels; NULL (default) keeps the theme default.

year_range

Optional c(from, to) years fixing the time axis, so a short trajectory can be shown on the same window as a long one (e.g. compare a young tr::c1g14 against tr::c1g1). NULL (default) fits the drawn trajectories; a wider range only extends the axis (it never drops data).

palette

Optional named colour vector overriding the default hues (keyed by trajectory traj_id).

title

Plot title; NULL (default) derives one from target.

Value

A ggplot object.

Details

  • x = publication year (Sugiyama layers); the y-axis has no intrinsic meaning (a branching position).

  • Line width grows with cumulative tracked documents along the trajectory.

  • A single-year feeder has no edge to draw as a line and is dropped (it would otherwise show a label/legend with no visible line); a single-year central (the selected final, e.g. a final-year-only community like tr::c1g17) is kept and drawn as a point.

  • Colour is per trajectory. With a single targeted final the legend is summarised to trN: p% (n) – n of trN's papers landed in that final, which is p% of trN's size (the feeders' counts overlap, so they do not sum to the final's total). With target = "all" it shows the full split trN -> c1g1:n, c1g2:n. A central is tr::cNgN (final, n), where n is the documents that remained in its final-year community (the last point of its size curve), not the cumulative documents the trajectory ever held.

See also

plot_trajectory_lines_3d(), plot_trajectory_confluence(), sniff_trajectory_braid(), sniff_trajectory_confluence()

Other visualization: plot_groups_influence_matrix(), plot_groups_influence_network(), plot_groups_lineage_2d(), plot_groups_lineage_3d(), plot_groups_map(), plot_groups_map_animation(), plot_groups_map_interactive(), plot_groups_per_year(), plot_trajectory_confluence(), plot_trajectory_confluence_interactive(), plot_trajectory_confluence_matrix(), plot_trajectory_dag(), plot_trajectory_dag_interactive(), plot_trajectory_dispersion(), plot_trajectory_dynamics(), plot_trajectory_dynamics_interactive(), plot_trajectory_formation(), plot_trajectory_lines_3d()

Examples

if (FALSE) { # \dontrun{
flow <- sniff_trajectory_braid(docs_per_group)
plot_trajectory_lines_2d(flow, min_n = 20)
plot_trajectory_lines_2d(flow, target = "tr::c1g1")
} # }