ssReflect: Reflection boundary correction for "sampSurf" Objects
In ssWavelets: Wavelet Functionality for Package 'sampSurf'

Description Usage Arguments Details Value Author(s) References See Also Examples

This routine takes a “sampSurf” object and makes a larger “Raster” object with copies of the original all around it using reflection.

Reflection is specifically used for correction of “edge effect” in the application of a MODWT wavelet filter as discussed in detail in Lark and Webster (2004); see details below.

1	ssReflect(ss, ...)

`ss`	An object of class “`sampSurf`”.
`...`	Gobbled.

This routine may be used stand-alone, but its main use it to be called from within ssMODWT when constructing objects of class “ssMODWT”. In this case, the filter is applied to the extended raster scene encompassing the reflected replicates and then clipped back to the original extents of the “sampSurf” image for further processing.

It should be kept in mind that the ssMODWT constructor uses the waveslim code for the decomposition. This code always applies a periodic correction to the image. Therefore, if one chooses the reflection as well, the periodic correction is applied to the extended relected image set in the decomposition.

A “Raster” image padded in all directions using the reflection correction.

Jeffrey H. Gove

: R. M. Lark and R. Webster. 2004. Analysing soil variation in two dimensions with the discrete wavelet transform. European Journal of Soil Science, 55:777–797.

ssToroid

#
# creates a sampSurf object with horizontal point sampling
# then applies reflection...
#
tr = Tract(c(x = 64, y = 64), cellSize = 1) #square tract ~0.5ha
btr = bufferedTract(10, tr)
ag3m = angleGauge(3)        #metric BAF
sshps = sampSurf(10, btr, iZone = 'horizontalPointIZ', angleGauge = ag3m,
        topDiam = c(0,0), startSeed = 123)
refhps = ssReflect(sshps)    #raster object
## Not run: 
plot(refhps, col = palMODWT(100, range=cellStats(refhps, range)))
plot(perimeter(sshps), add = TRUE)

## End(Not run)