Alternative point distance (and direction) calculations

Source: R/distanceFromEachPoint.R

These have been written with speed in mind.

.pointDistance(
  from,
  to,
  angles = NA,
  maxDistance = NA_real_,
  otherFromCols = FALSE
)

Arguments

from

Numeric matrix with 2 or 3 or more columns. They must include x and y, representing x and y coordinates of "from" cell. If there is a column named "id", it will be "id" from to, i.e,. specific pair distances. All other columns will be included in the return value of the function.

to

Numeric matrix with 2 or 3 columns (or optionally more, all of which will be returned), x and y, representing x and y coordinates of "to" cells, and optional "id" which will be matched with "id" from from. Default is all cells.

angles

Logical. If TRUE, then the function will return angles in radians, as well as distances.

maxDistance

Numeric in units of number of cells. The algorithm will build the whole surface (from from to to), but will remove all distances that are above this distance. Using this will keep memory use down.

otherFromCols

other columns to use as 'from'

Value

A matrix with one row per from-to pair, carrying the columns of from plus "dists", the distance between from and to. angles = TRUE adds an "angles" column, otherFromCols adds the named columns of from, and a non-NA maxDistance adds "keptIndex", the index of each retained pair in the unfiltered set.