2025 Volume 63 Issue 4 Pages 1-16
Inoh’s Map was drawn from manuscript maps called Shita-ezu（1/36000）, Yosezu（1/36000）, Chuuzu-shitazu（1/216000） and Shouzu-shitazu（1/432000）. The two databooks on the mapping process of these maps have been handed down in Inoh Tadataka Museum. In these databooks, the east-west/south-north component distances between main survey points, the same component distances from the orign where is Inoh’s residence in Edo or Okazakimura where is starting point in Shikoku Island to each survey point and the difference of latitude between the origin and each survey point are written down.
There are three series of component distances, namely former, middle and latter data and differnces of latitude, namely former and latter data. The following process of mapping of the manuscript maps has been clarified from the analysis of theese series.
After the former east-west/south-north component distances between main survey points are measured on Shita-ezu or Yosezu, plotted points are revised slightly and the middle data are resulted. As the differnce of adjustment is still existed, survey points are rivised moreover. As the result, the difference of adjustment reduced to the negligible level on Yosezu. About east-west component distances, revising to east prevails toward west. Revising to south toward west prevails about south-north component distances.
Concerning the latitude differences between the orign where is Inoh’s residence in Edo and each main survey points, there are former and latter two data calculated from south-north component distances and the latitude differences found by astronomical survey. After revising the survey points, the gaps between the astronomical values and calculated values are still existed. The astronomical latitude differnces are not utilized.
