trajectoryProjection: Trajectory projection

In ecotraj: Ecological Trajectory Analysis

Trajectory projection

Description

Performs an projection of a set of target points onto a specified trajectory and returns the distance to the trajectory (i.e. rejection) and the relative position of the projection point within the trajectory.

Usage

trajectoryProjection(
  d,
  target,
  trajectory,
  tol = 1e-06,
  add = TRUE,
  force = TRUE
)

Arguments

d	A symmetric matrix or an object of class dist containing the distance values between pairs of ecological states (see details).
target	An integer vector of the ecological states to be projected.
trajectory	An integer vector of the ecological states conforming the trajectory onto which target states are to be projected.
tol	Numerical tolerance value to determine that projection of a point lies within the trajectory.
add	Flag to indicate that constant values should be added (local transformation) to correct triplets of distance values that do not fulfill the triangle inequality.
force	Flag to indicate that when projection falls out of the reference trajectory for a given, the closest point in the trajectory will be used.

Value

A data frame with the following columns:

• distanceToTrajectory: Distances to the trajectory, i.e. rejection. If there is no orthogonal projection the distance corresponds to the minimum distance to the trajectory.

• segment: Segment that includes the projected point or the closest state.

• relativeSegmentPosition: Relative position of the projected point within the segment, i.e. values from 0 to 1 with 0 representing the start of the segment and 1 representing its end.

• relativeTrajectoryPosition: Relative position of the projected point within the trajectory, i.e. values from 0 to 1 with 0 representing the start of the trajectory and 1 representing its end.

Author(s)

Miquel De Cáceres, CREAF

ecotraj documentation built on June 8, 2025, 11:24 a.m.