This spell was used by Cuthbert Sinclair, and later by Sam (accompanied by Crowley) to access Cuthbert Sinclair's secret hideout. Because Cuthbert Sinclair's secret hideout was heavily warded and rendered it invisible and intangible, made this place unplottable. To access an unplottable place like this, a special spell was required to access it. The spell was only shown in Blade Runners