cells: Get cell numbers

Description Usage Arguments Value Examples

Description

Get the cell numbers covered by a SpatVector or SpatExtent. Or that match values in a vector; or all non NA values.

Usage

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## S4 method for signature 'SpatRaster,missing'
cells(x, y)

## S4 method for signature 'SpatRaster,numeric'
cells(x, y)

## S4 method for signature 'SpatRaster,SpatVector'
cells(x, y, method="simple", weights=FALSE, exact=FALSE, touches=is.lines(y))

## S4 method for signature 'SpatRaster,SpatExtent'
cells(x, y)

Arguments

x

SpatRaster

y

SpatVector, SpatExtent, 2-column matrix representing points, numeric representing values to match, or missing

method

character. Method for getting cell numbers for points. The default is "simple", the alternative is "bilinear". If it is "bilinear", the four nearest cells and their weights are returned

weights

logical. If TRUE and y has polygons, the approximate fraction of each cell that is covered is returned as well

exact

logical. If TRUE and y has polygons, the exact fraction of each cell that is covered is returned as well

touches

logical. If TRUE, values for all cells touched by lines or polygons are extracted, not just those on the line render path, or whose center point is within the polygon. Not relevant for points

Value

numeric vector or matrix

Examples

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r <- rast(ncols=10, nrows=10)
values(r) <- 1:ncell(r)
r[c(1:25, 31:100)] <- NA
r <- ifel(r > 28, r + 10, r)

# all cell numbers of cells that are not NA
cells(r)

# cell numbers that match values
x <- cells(r, c(28,38))
x$lyr.1

# cells for points
m <- cbind(x=c(0,10,-30), y=c(40,-10,20))
cellFromXY(r, m)

v <- vect(m)
cells(r, v)
cells(r, v, method="bilinear")

# cells for polygons
#f <- system.file("ex/lux.shp", package="terra")
#v <- vect(f)
#r <- rast(v)
#cv <- cells(r, v) 

terra documentation built on Oct. 11, 2021, 9:09 a.m.