Is there an R equivalent of NEAR in ESRI ArcGIS?

Question

I have 54 points in one data set A I have 300+ data points in a dataset B.

I wish to find the distance for each point in dataset-set B, to points in dataset A.

Nearest Neighbor packages appear to only find neighbors within a given data-set, not a second data set.

rdist was close, but I didn't want a matrix, just nearest.--"Given two sets of locations computes the full Euclidean distance matrix among all pairings or a sparse version for points within a fixed threshhold distance."

This looked good, saying "Read two geocoded point sets from Comma Separated Value (CSV) files into R data objects. Assign to each member of first point set the geographically closest point from second set" but is so dated (2010), so something more recent must exist...

Same issue with this

Other packages find distances between points and lines, points and polygons, etc. viz: http://cran.r-project.org/web/packages/geosphere/geosphere.pdf

The omission of P2P suggests I am missing something simple...

Answer 1

UPDATE:

The FNN package has a function get.knnx which can compute the N-nearest neighbours in point patterns. For what you want, this should work:

nn = get.knnx(A,B,k=1)

Which should just return the nearest neighbors between the two datasets. You can also specify what nearest neighbor algorithm it will use, be it kd_tree, cover_tree, CR, or brute force.

---

spatstat has a crossdist function.

Description

Computes the distances between pairs of ‘things’ taken from two different datasets.

It takes two point patterns A and B as inputs, and returns the matrix whose [i,j] entry is the distance from A[i] to B[j]. To get the nearest neighbors between two datasets using crossdist:

xdistances <- crossdist(A, B)  #Get all cross distances    

nn = numeric() 
for (i in 1:nrow(A)) {   
  xdistance <- sort(xdistances[i,], partial=1)[1]   
  nn <- append(nn, xdistance)
}

I hope that helps.

Answer 2

RANN looked like the package I was looking for, but was not... RANN gives the nearest neighbor for CELLS, not an XY point layer.

FNN was the package I was looking for.

Alternates methods exist, but share commonalities: All methods make use of a) A distance function b) loop or apply c) A 'min' of the distance function

Examples:

https://stackoverflow.com/questions/22121742/calculate-the-distance-between-two-points-of-two-datasets-nearest-neighbor

https://stackoverflow.com/questions/21977720/r-finding-closest-neighboring-point-and-number-of-neighbors-within-a-given-rad