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 coordinate(s)

y coordinate(s)

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

lns

SpatialLines object

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.

Examples

Run this code

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)

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