segments_to_vertices: Transform segments to vertices

In theMILOlab/SPATA2: A Toolbox for Spatial Expression Analysis

Transform segments to vertices

Description

This function takes a data frame of arcs (segments) and constructs an ordered sequence of vertices to outline a connected, non-intersecting polygon.

Usage

segments_to_vertices(arcs_df)

Arguments

arcs_df

A data frame containing arc information with columns: x1, y1: Starting coordinates of each segment x2, y2: Ending coordinates of each segment idx: An identifier for each segment

Details

This function iteratively selects arcs that connect to form a polygon. If an arc’s endpoint does not match any available arc’s start or endpoint, it selects the nearest arc using a nearest-neighbor search. Segments that would cause intersections are removed. If the constructed polygon closes on itself, it terminates the process.

Value

A data frame (outline_df) containing the vertices (x, y coordinates and idx) that form the ordered outline of the polygon.

Examples

# Sample data frame of arcs

arcs_df <- data.frame(
  x1 = c(0, 1, 2),
  y1 = c(0, 1, 0),
  x2 = c(1, 2, 0),
  y2 = c(1, 0, 0),
  idx = c(1, 2, 3)
)
segments_to_vertices(arcs_df)

theMILOlab/SPATA2 documentation built on June 1, 2025, 9:11 p.m.