temporal_interpolate: Fill gaps across bands using moving mean window

In ursa: Non-Interactive Spatial Tools for Raster Processing and Visualization

Fill gaps across bands using moving mean window

Description

temporal_interpolate is applicable for multiband raster image, where bands are regular timestamps or period. For each cell (local operation of map algebra), NA value is replaced by averaging of two closest values (one value before, one value later) inside of moving window.

Usage

temporal_interpolate(obj, win = 7, cover = 0, verbose = FALSE)

Arguments

obj	Object of class ursaRaster or matrix, where spatial locations are by rows and temporal observations are by columns.
win	Positive integer. Size of moving window. Required odd value; otherwise is coerced to the closest odd integer.
cover	Not applicable. For consistence call with temporal_mean.
verbose	Logical. TRUE provides some additional information on console. Default is FALSE.

Details

Function uses weighted averaging depending of proximity of found non-NA values. For example, if ind is temporal index of NA value in the center of movind window, indL=ind-2 is temporal index of the closest early value valL, and indR=ind+1 is temporal index of the closest late value valR, then result is ⁠val <- (1/3) * valL + (2/3) * valR⁠.

Value

ursaRaster object, if obj is object of class ursaRaster.

matrix object, if obj is a matrix.

Author(s)

Nikita Platonov [e-mail]

See Also

temporal_mean

Examples

session_grid(NULL)
n <- 45 # bands
m <- 3 # sample size
k <- median(seq(n))+seq(m)-(m %/% 2)-1 ## sample subset
s <- 5 # window size
a <- round(ursa_dummy(n,min=-60,max=60,elements=15,mul=1/8))
a[a<(-40)] <- NA
b <- temporal_interpolate(a,7)
p1 <- colorize(a,lazy=TRUE)
p2 <- colorize(b,lazy=TRUE,colortable=p1)
display(list('Source'=p1[k],'Gaps are filled'=p2[k]),layout=c(2,NA)
       ,legend=list(list(1,"right"),list(2,"right")),decor=FALSE)

ursa documentation built on Sept. 30, 2024, 9:35 a.m.