distancetotrap {secr} | R Documentation |
Compute Euclidean distance from each of a set of points to the nearest detector in an array, or return the sequence number of the detector nearest each point.
distancetotrap(X, traps) nearesttrap(X, traps)
X |
coordinates |
traps |
traps object or 2-column matrix of coordinates |
distancetotrap
returns the distance from each point in X to the
nearest detector in traps
. It may be used to restrict the points
on a habitat mask.
distancetotrap
returns a vector of distances (assumed to be in metres).
nearesttrap
returns the index of the nearest trap.
It is no longer (from version 2.3.0) necessary for ‘traps’ to be a traps object. It may be any 2-column matrix or dataframe of coordinates. From version 2.6.0 ‘traps’ may also be a simple (one-polygon) SpatialPolygonsDataFrame object from sp, in which case distances are to the boundary vertices (use with care!).
## restrict a habitat mask to points within 70 m of traps ## this is nearly equivalent to using make.mask with the ## `trapbuffer' option temptrap <- make.grid() tempmask <- make.mask(temptrap) d <- distancetotrap(tempmask, temptrap) tempmask <- subset(tempmask, d < 70)