Analysis of investigating the presence of "Yama-ate" phenomenon using GIS - Methodology analysis of measuring the positional relationship between mountaintop and its observer's viewpoint

So-called "Yama-ate" phenomenon is often recognized in many Castle Towns in Japan, a state of things that a certain mountaintop is seen at the end of the centerline of a road in urban area. In former papers, we used to attempt to build the methodology of investigating this "Yama-ate" phenomenon using GIS. Based on the result, we newly conduct the report of two methods of measuring its presence, such as investigating the presence of "Yama-ate" phenomenon using Differential-GPS, which provide high accuracy positional information, and creating the methodology of specifying the coordinate value of the ostensible mountaintop, using altitude value of commonly-available.