Cost layer issues

the create_accum_cost function expects an 'origin' of the closest town to be inside the AOI. Where outside returns an error "invalid vertex names". Need to find and reconsitute Kiri's original scripts for Deception

Start by locating the create_accum_cost function and examining how it handles an origin outside the AOI. Then look for Kiri's original scripts for Deception and determine whether they can be reconstructed; done should include a defined resolution for the invalid vertex names error and the recovered Deception workflow.

Written by the indexing model from the issue text.