How many cells past the focus the bounding box goes.
Whether or not this neighborhood has a mask the cursor of it's bounding box
The radius of the inner circle of the Annulus.
Overridden to define the mask of Neighborhoods that have one col and row treat the mask as a raster, that is, (0,0) is the upper left corner, and (extent*2+1,extent*2+1) is the lower right corner
The radius of the outer circle of the Annulus.