raster2sample: raster2sample
In RRemelgado/fieldRS: Remote Sensing Field Work Tools

Description Usage Arguments Details Value See Also Examples

Converts a raster grid to points.

1	raster2sample(x)

`x`	Object of class SpatialPolygons or SpatialPolygonDataFrame.

poly2Sample extends on the rasterToPoints function from the raster package. For each non-NA pixel in x, the function will use 3x3 moving window and report on the frequency of non-NA pixels. This can be useful to identify "pure" samples within a clump of pixels (i.e. high frequency) as well as mixed pixels along their borders (i.e. low frequency). The output is a SpatialPointsDataFrame reporting on:

x - x coordinate.
y - y coordinate.
cover - Non-NA value frequency.
id - Corresponding raster value in x.

A SpatialPointsDataFrame with sampled pixels reporting on pixel compactness.

poly2sample ccLabel

{

 require(raster)

 # load example image
 r <- raster(system.file("extdata", "ndvi.tif", package="fieldRS")[1])
 r[r < 5000] <- NA
 
 # extract samples
 samples <- raster2sample(r)

}