cpp

Author: rhijmans

src/RcppModule.cpp

@@ -998,6 +998,7 @@ RCPP_MODULE(spat){
 		.method("sampleRowColRaster", &SpatRaster::sampleRowColRaster)
 		.method("sampleRegularValues", &SpatRaster::sampleRegularValues)
 		.method("sampleRowColValues", &SpatRaster::sampleRowColValues)
+		.method("sampleRowCol", &SpatRaster::sampleRowCol)
 		.method("sampleRandomRaster", &SpatRaster::sampleRandomRaster)
 		.method("sampleRandomValues", &SpatRaster::sampleRandomValues)
 		.method("scale", &SpatRaster::scale)

src/sample.cpp

@@ -300,6 +300,31 @@ std::vector<std::vector<double>> SpatRaster::sampleRowColValues(size_t nr, size_
 }
 
 
+std::vector<double> SpatRaster::sampleRowCol(size_t nr, size_t nc) {
+
+	std::vector<double> out;
+	if (!source[0].hasValues) return (out);
+	if ((nr == 0) || (nc ==0)) {
+		return(out);
+	}
+	nr = std::min(nr, nrow());
+	nc = std::min(nc, ncol());
+
+	std::vector<int_64> rows, cols;
+
+	double d = nrow()/nr;
+	for (size_t i=0; i<nr; i++) {
+		rows.push_back((i + .5) * d);
+	}
+	d = ncol()/nc;
+	for (size_t i=0; i<nc; i++) {
+		cols.push_back((i + .5) * d);
+	}
+	return cellFromRowColCombine(rows, cols);
+}
+
+
+
 std::vector<size_t> sample_replace(size_t size, size_t N, unsigned seed){
 	std::default_random_engine gen(seed);
 	std::uniform_int_distribution<> U(0, N-1);

src/spatRaster.h

@@ -829,6 +829,7 @@ class SpatRaster {
 		SpatRaster sampleRowColRaster(size_t nr, size_t nc, bool warn);
 		SpatRaster sampleRandomRaster(double size, bool replace, unsigned seed);
 		std::vector<std::vector<double>> sampleRegularValues(double size, SpatOptions &opt);
+		std::vector<double> sampleRowCol(size_t nr, size_t nc);
 		std::vector<std::vector<double>> sampleRowColValues(size_t nr, size_t nc, SpatOptions &opt);
 
 		std::vector<std::vector<double>> sampleRandomValues(double size, bool replace, unsigned seed);