walkthrough solution to the boundary overlap problem

Existing methods for eliminating bias due to boundary overlap suffer some disadvantages in practical use, including the need to work outside the tract, restrictions on the kinds of boundaries to which they are applicable, and the possibility of significantly increased variance as a price for unbiasedness. We propose a new walkthrough method for reducing boundary overlap bias that diminishes or eliminates the need to work outside the tract and accommodates irregular boundaries easily. Under typical conditions, the walkthrough method eliminates the boundary overlap bias associated with most objects near the border and reduces it for the remaining objects. The walkthrough method is object-centered in conception and implementation, but the measurements required are simple. The walkthrough method complements existing methods for correcting boundary overlap bias and should prove especially helpful when conditions make existing methods difficult or impossible to use.