Translation of "평면도법" in English

레오나르도는 이몰라를 "평면도법" 지도로 보여줄 필요가 있었는데

Leonardo needed to show Imola as an “ichnographic” map — an idea that

이 모든 초기의 평면도법 지도에는 별표가 있는데

All these early ichnographic maps have asterisks - this one was spotted with its own inaccuracies