| adjacent {hero} | R Documentation |
Determine adjacent points
Description
adjacent attempts to find the point(s) adjacent
(closest) to each point. The data are implicitly assumed
to be on a grid, otherwise this function isn't very
useful. Distances between each point and other points in
coords are computed and then rounded using the
round function. Let k denote
the minimum distance between a reference point and all
other points. A point is adjacent to the reference point
if (after rounding), it's distance from the reference
point matches the minimum distance k.
Usage
adjacent(coords, longlat = FALSE, digits = 1)
Arguments
coords |
A two-dimensional matrix-like object with non-NULL dimensions. |
longlat |
A logical value indicating whether Great
Circle distances should be used ( |
digits |
The number of digits to use when applying
|
Details
digits is the number of digits used by
round in the rounding process.
Value
A hero_adjacent object. This is simply a
list with elements nbrs and coords.
nbrs is a list specifying the adjacent points
for each point. coords is simply the original
coords supplied to the function and is retained
for plotting purposes.
Examples
# basic coordinates
coords = expand.grid(1:4, 1:4)
# plot coordinates to see relationships
plot(coords, type = "n")
text(coords)
a = adjacent(coords, digits = 1)
plot(a)