noun
floor plan; map of the inside of a building or station
Refers to a diagram or map showing the interior layout of a building, station, hospital, campus, etc. Often found on signs or pamphlets.
駅の構内図を見て、トイレの場所を確認した。
I checked the station map to find the restroom.
病院の構内図が入り口に貼ってある。
A map of the hospital interior is posted at the entrance.
案内図 is a guide map, often for a wider area like a park or neighborhood, while 構内図 is limited to the inside of a specific structure.
Compound of 構内 (inside the premises) and 図 (diagram, map). The reading こうないず follows standard on'yomi.