VeloxRaster_im2col: im2col

In velox: Fast Raster Manipulation and Extraction

Description

Creates a matrix of flattened image patches from a VeloxRaster band. Order is left-to-right, top-to-bottom. Note that if any(c(rowframe, colframe)>0), the image patches are (partially) overlapping.

Arguments

wrow	Patch size in the y dimension.
wcol	Patch size in the x dimension.
band	The band to be flattened.
padval	A padding value.
rowframe	A non-negative integer specifying the size of the frame around the image patches in the y dimension.
colframe	A non-negative integer specifying the size of the frame around the image patches in the x dimension.
rowstride	A positive integer denoting the stride between extracted patches in the y dimension. I.e. only every rowstrideth patch is extracted.
colstride	A positive integer denoting the stride between extracted patches in the x dimension. I.e. only every colstrideth patch is extracted.

Value

A numeric matrix with (wrow+2*rowframe)*(wcol+2*colframe) columns.

Examples

## Make VeloxRaster
mat <- matrix(1:100, 10, 10)
vx <- velox(mat, extent=c(0,1,0,1), res=c(0.1,0.1), crs="+proj=longlat +datum=WGS84 +no_defs")
## Apply im2col
patch.mat <- vx$im2col(wrow=2, wcol=2, band=1, padval=0,
                       rowframe=1, colframe=1, rowstride=2, colstride=2)
dim(patch.mat)

velox documentation built on May 2, 2019, 6:01 a.m.