Method and system for extracting CAD building boundary based on segmented recursion and storage medium

The invention discloses a method for extracting a CAD (computer-aided design) building boundary based on segmented recursion, which comprises the following steps of: firstly, breaking according to a CAD line, and establishing an R tree index; determining an extraction boundary starting point; according to the extracted boundary starting point, extending on the building drawing according to a preset step length until contacting with any boundary line of the building boundary to obtain a contact boundary line; obtaining the direction of the contact boundary line, finding out all line segments consistent with the direction of the contact boundary line, and connecting the end points of all the line segments according to the direction vertical to the direction of the contact boundary line to form a boundary frame in the direction; then finding out all line segments in the same direction from the vertical direction, and repeating the steps until the boundary frames in the four directions of the building drawing are