It could be an inset.
http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/b/bd/Drury_lane_inset_map.png&imgrefurl=http://commons.wikimedia.org/wiki/Image:Drury_lane_inset_map.png&h=372&w=613&sz=377&tbnid=zl_73H_RR4AJ::&tbnh=83&tbnw=136&prev=/images%3Fq%3Dinset%2Bmap&hl=en&usg=__nxVHgShmfh5QC-AkpjANkCr277o=&sa=X&oi=image_result&resnum=4&ct=image&cd=1
What is the detailed representation of a specific area on a map called?
2 answers
'what the est says about habitable