니산현이 자연 조건상 평야가 많은 은진현과 산지가 많은 연산현의 중간적 특성을 지닌 지역임을 고려해 볼 때 쉽게 짐작이 가는 사실이다.
Considering that Nisan-hyeon was an area with the middle characteristics of Eunjin-hyeon, which had a lot of plains, and Yeonsan-hyeon, which had a lot of mountainous areas, it is easy to guess.