Yap's secret technique Images of the entire set of Taiwan Bao maps can be browsed at the Academia Sinica website Taiwan History and Culture in Time and Space. But Yap's magnum opus is the product of incomparable patience: he spent three years mapping the boundaries of 2,991 machi and sho from 466 sheets of the Taiwan Bao maps, and digitizing them through GIS technology.
達人「密技」完整的台灣堡圖影像如今在中研院「台灣歷史文化地圖」網站上已可瀏覽，而葉高華的創舉，是以無比的耐心，前後耗費了 3 年時間，將總計 466 張堡圖中，總計達 2,991 個的街、庄邊界，以 GIS 技術加以數值化。