The raster functions for cell abstraction

The following functions in the raster package are designed to work with cell indexes.

fun(r, cell)

• [
• adjacent
• colFromCell
• extentFromCells
• rasterFromCells
• rowColFromCell
  
• rowFromCell
• validCell
• xyFromCell
• xFromCell
• yFromCell

The following functions will return cell indexes.

fun(r, query) to return cells

• cellFromCol
• cellFromLine
• cellFromPolygon
• cellFromRow
• cellFromRowCol
• cellFromRowColCombine
• cellFromXY
• cellsFromExtent
• fourCellsFromXY

Others

• setValues will work as fun(r, vals, index) only for RasterLayerSparse
• extent(Raster, r1, r2, c1, c2) to crop an extent by row/column