Enforcement Rules of the Land Expropriation Act Article 20

If a land is partially expropriated, the municipal or county (city) competent authority shall request the registry authority to conduct registration of subdivision survey of the land, and publicly announce the expropriation of the subdivided land based on the new land description after the registration.
中文原文 土地徵收條例施行細則第20條
一宗土地部分被徵收者,直轄市或縣(市)主管機關應於公告徵收前,囑託該管登記機關就徵收之部分辦理分割測量登記,並以分割登記後之土地標示辦理公告徵收。

English translation for reference only; the Chinese text prevails. Not legal advice.