In addition, a roller can be used to specify the scale of the grid, making it finer or courser as needed for the application.
One option is to aggregate areas and to use a much courser zone system for tabulating flows.
British Dictionary definitions for courser
a person who courses hounds or dogs, esp greyhounds
a hound or dog trained for coursing
(literary) a swift horse; steed
C13: from Old French coursier, from courscourse
a terrestrial plover-like shore bird, such as Cursorius cursor (cream-coloured courser), of the subfamily Cursoriinae of desert and semidesert regions of the Old World: family Glareolidae, order Charadriiformes
C18: from Latin cursōrius suited for running, from cursuscourse