for #1257

rspatial · Sep 9, 2023 · 29ca1f1 · 29ca1f1
1 parent f4e02ac
commit 29ca1f1
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Showing 2 changed files with 12 additions and 4 deletions.
diff --git a/R/extract.R b/R/extract.R
@@ -478,7 +478,7 @@ function(x, y, ...) {
 
 
 
-extractAlong <- function(x, y, ID=TRUE, cells=FALSE, xy=FALSE) { 
+extractAlong <- function(x, y, ID=TRUE, cells=FALSE, xy=FALSE, online=FALSE) { 
 
 	stopifnot(inherits(x, "SpatRaster"))
 	if (inherits(y, "sf")) {
@@ -551,7 +551,14 @@ extractAlong <- function(x, y, ID=TRUE, cells=FALSE, xy=FALSE) {
 	} else {
 		colnames(res) <- c("ID", "cell", names(x))
 		if (xy) {
-			res <- data.frame(res[,1:2], xyFromCell(x, res$cell), res[, -c(1:2), drop=FALSE])
+			xycrd <- xyFromCell(x, res$cell)
+			if (online) {
+				pts <- vect(xycrd, crs="local")
+				crs(y) <- "local"
+				n <- nearest(pts, y)
+				xycrd <- crds(n)
+			}
+			res <- data.frame(res[,1:2], xycrd, res[, -c(1:2), drop=FALSE])
 		}
 	}
 	if (!cells) res$cell <- NULL

diff --git a/man/extractAlong.Rd b/man/extractAlong.Rd
@@ -9,15 +9,16 @@ Extract raster values along a line. That is, the returned values are ordered alo
 }
 
 \usage{
-extractAlong(x, y, ID=TRUE, cells=FALSE, xy=FALSE)
+extractAlong(x, y, ID=TRUE, cells=FALSE, xy=FALSE, online=FALSE)
 }
 
 \arguments{
   \item{x}{SpatRaster}
   \item{y}{SpatVector with lines geometry}
   \item{ID}{logical. Should an ID column be added? If so, the first column returned has the IDs (record numbers) of input SpatVector \code{y}}
   \item{cells}{logical. If \code{TRUE} the cell numbers are also returned}
-  \item{xy}{logical. If \code{TRUE} the coordinates of the cells are also returned. See \code{\link{xyFromCell}}}
+  \item{xy}{logical. If \code{TRUE} the coordinates of the cells traversed by \code{y} are also returned. See \code{\link{xyFromCell}}}
+  \item{online}{logical. If \code{TRUE} the returned coordinates are snapped to \code{y}} 
 }
 
 \value{