fixes #1408

R/tiles.R

@@ -1,23 +1,26 @@
 
 setMethod("makeTiles", signature(x="SpatRaster"),
-	function(x, y, filename="tile_.tif", extend=FALSE, na.rm=FALSE, overwrite=FALSE, ...) {
+	function(x, y, filename="tile_.tif", extend=FALSE, na.rm=FALSE, buffer=0, overwrite=FALSE, ...) {
 		filename <- trimws(filename[1])
 		filename <- filename[!is.na(filename)]
 		if (filename == "") error("makeTiles", "filename cannot be empty")
 		opt <- spatOptions(filename="", overwrite=overwrite, ...)
 		if (inherits(y, "SpatRaster")) {
-			ff <- x@cpp$make_tiles(y@cpp, extend[1], na.rm[1], filename, opt)
+			ff <- x@cpp$make_tiles(y@cpp, extend[1], buffer, na.rm[1], filename, opt)
 		} else if (inherits(y, "SpatVector")) {
+			if (!all(buffer == 0)) {
+				warn("makeTiles", "argument 'buffer' is ignored if y is a SpatVector")
+			}
 			ff <- x@cpp$make_tiles_vect(y@cpp, extend[1], na.rm[1], filename, opt)		
 		} else if (is.numeric(y)) {
 			if (length(y) > 2) {
 				error("makeTiles", "expected one or two numbers")
 			}
 			y <- rep_len(y, 2)
 			y <- aggregate(rast(x), y)
-			ff <- x@cpp$make_tiles(y@cpp, extend[1], na.rm[1], filename, opt)			
+			ff <- x@cpp$make_tiles(y@cpp, extend[1], buffer, na.rm[1], filename, opt)			
 		} else {
-			error("makeTiles", "y must be a SpatRaster or SpatVector")
+			error("makeTiles", "y must be numeric or a SpatRaster or SpatVector")
 		}
 		messages(x, "makeTiles")
 		ff

man/makeTiles.Rd

@@ -15,7 +15,7 @@ Divide a SpatRaster into "tiles". The cells of another SpatRaster (normally with
 }
 
 \usage{
-\S4method{makeTiles}{SpatRaster}(x, y, filename="tile_.tif", extend=FALSE, na.rm=FALSE, overwrite=FALSE, ...)
+\S4method{makeTiles}{SpatRaster}(x, y, filename="tile_.tif", extend=FALSE, na.rm=FALSE, buffer=0, overwrite=FALSE, ...)
 }
 
 \arguments{
@@ -24,6 +24,7 @@ Divide a SpatRaster into "tiles". The cells of another SpatRaster (normally with
   \item{filename}{character. Output filename template. Filenames will be altered by adding the tile number for each tile}
   \item{extend}{logical. If \code{TRUE}, the extent of \code{y} is expanded to assure that it covers all of \code{x}}
   \item{na.rm}{logical. If \code{TRUE}, tiles with only missing values are ignored}
+  \item{buffer}{integer. The number of cells to add around each tile. Ignored if \code{y} is a SpatVector. Can be a single number, or two numbers to specify a separate buffer for the rows and for the columns. This allows for creating overlapping tiles that can be used for computing spatial context dependent values with e.g. \code{\link{focal}}. The expansion is only inside \code{x}, no rows or columns outside of \code{x} are added}
   \item{overwrite}{logical. If \code{TRUE}, existing tiles are overwritten; otherwise they are skipped (without error or warning)}
   \item{...}{additional arguments for writing files as in \code{\link{writeRaster}}}
 }

src/raster_methods.cpp

@@ -115,15 +115,34 @@ SpatExtent SpatRaster::ext_from_cell(double cell) {
 }
 
 
-std::vector<std::string> SpatRaster::make_tiles(SpatRaster x, bool expand, bool narm, std::string filename, SpatOptions &opt) {
+std::vector<std::string> SpatRaster::make_tiles(SpatRaster x, bool expand, std::vector<int> buffer, bool narm, std::string filename, SpatOptions &opt) {
 
 	std::vector<std::string> ff;
 	if (!hasValues()) {
 		setError("input raster has no values");
 		return ff;
 	}
+
+
 	x = x.geometry(1, false, false, false);
 	SpatExtent e = getExtent();
+
+	recycle(buffer, 2);
+//	if ((buffer[0] < 0) | (buffer[1] < 0)) {
+//		setError("buffer cannot be negative");
+//		return ff;
+//	}
+	std::vector<double> ebuf = {buffer[0] * xres(), buffer[1] * yres()};	
+
+/*
+	if ((buffer[0] > 0) || (buffer[1] > 0)) {
+		e.xmin = e.xmin - ebuf[0];
+		e.xmax = e.xmax + ebuf[0];
+		e.ymin = e.ymin - ebuf[1];
+		e.ymax = e.ymax + ebuf[1];
+	}
+*/
+
 	SpatOptions ops(opt);
 	if (expand) {
 		x = x.extend(e, "out", NAN, ops);
@@ -145,6 +164,11 @@ std::vector<std::string> SpatRaster::make_tiles(SpatRaster x, bool expand, bool
 			continue;
 		}
 		SpatExtent exi = x.ext_from_cell(i);
+		exi.xmin = exi.xmin - ebuf[0];
+		exi.xmax = exi.xmax + ebuf[0];
+		exi.ymin = exi.ymin - ebuf[1];
+		exi.ymax = exi.ymax + ebuf[1];
+
 		opt.set_filenames({fout});
 		SpatRaster out = crop(exi, "near", false, opt);
 		if (out.hasError()) {

src/spatRaster.h

@@ -726,7 +726,8 @@ class SpatRaster {
 		SpatExtent ext_from_rc(int_64 r1, int_64 r2, int_64 c1, int_64 c2);
 		SpatExtent ext_from_cell(double cell);
 
-		std::vector<std::string> make_tiles(SpatRaster x, bool expand, bool narm, std::string filename, SpatOptions &opt);
+		std::vector<std::string> make_tiles(SpatRaster x, bool expand, std::vector<int> buffer, bool narm, std::string filename, SpatOptions &opt);
+
 		std::vector<std::string> make_tiles_vect(SpatVector x, bool expand, bool narm, std::string filename, SpatOptions &opt);
 
 		SpatRaster mask(SpatRaster &x, bool inverse, double maskvalue, double updatevalue, SpatOptions &opt);