raster (version 1.8-3)

cellFrom: Get cell, row, or column number

Description

Get cell number(s) of a Raster* object from row and/or column numbers. Cell numbers start at 1 in the upper left corner, and increase from left to right, and then from top to bottom. The last cell number equals the number of cells of the Raster* object.

Usage

cellFromRowCol(object, rownr, colnr)
cellFromRowColCombine(object, rownr, colnr)
cellFromRow(object, rownr)
cellFromCol(object, colnr)
colFromX(object, x)
rowFromY(object, y)
cellFromXY(object, xy)
cellFromLine(object, lns)
cellFromPolygon(object, p, weights=FALSE)

Arguments

object

Raster* object (or a SpatialPixels* or SpatialGrid* object)

colnr

column number; or vector of column numbers

rownr

row number; or vector of row numbers

x

x coordinate(s)

y

y coordinate(s)

xy

matrix of x and y coordinates, or a SpatialPoints or SpatialPointsDataFrame object

lns

SpatialLines object

p

SpatialPolygons object

weights

Logical. If TRUE, the fraction of each cell that is covered is also returned

Value

• row, column or cell number(s). cellFromLine and cellFromPolygon return a list.

Details

cellFromRowCol returns the cell numbers obtained for each row / col number pair. In contrast, cellFromRowColCombine returns the cell numbers obtained by the combination of all row and column numbers supplied as arguments.

See Also

xyFromCell

Examples

r <- raster(ncols=10, nrows=10)
cellFromRowCol(r, 5, 5)
cellFromRowCol(r, 1:2, 1:2)
cellFromRowColCombine(r, 1:3, 1:2)
cellFromCol(r, 1)
cellFromRow(r, 1)
colFromX(r, 0.5)
rowFromY(r, 0.5)
cellFromXY(r, c(0.5, 0.5))

cds1 <- rbind(c(-180,-20), c(-160,5), c(-60, 0), c(-160,-60), c(-180,-20))
cds2 <- rbind(c(80,0), c(100,60), c(120,0), c(120,-55), c(80,0))
pols <- SpatialPolygons(list(Polygons(list(Polygon(cds1)), 1), Polygons(list(Polygon(cds2)), 2)))
cellFromPolygon(r, pols)