From the 7th to 8th centuries, straight roads and grid-like city blocks aligned with the cardinal directions were constructed in the Nara Basin. This study examines the surveying techniques that may have been employed in their layout. One method likely involved observing circumpolar stars, particularly the simultaneous transit of two stars with nearly identical right ascensions. Another method utilized the directional lines of sunrise or sunset, whose azimuths remain stable for several days around the summer and winter solstices. These orientations were recorded in relation to prominent mountains and saddle-shaped features on the skyline.

This paper delineates the methodology for generating 3D models from aerial photographs furnished by the Geospatial Information Authority of Japan (GSI) employing Metashape, a photogrammetry software based on SfM/MVS. Subsequently, the features of “Landscape Time Machine” are introduced. This application was developed to visualize the past landscapes of various cities and regions in three-dimensional space.

The utilization of Metashape software facilitated the generation of 3D models of diverse geographical regions and temporal periods from the 400 dpi aerial photograph data accessible through the GSI’s Map and Aerial Photo Viewing Service. While the generated 3D models exhibited some components missing, such as in tower-like structures, this approach facilitates the construction of 3D models with a certain degree of quality. The visualization of past landscapes in 3D appeared to offer a more informative representation than two-dimensional maps, such as old topographic maps. The “Landscape Time Machine” application, which is based on JavaScript, allows users to view these 3D models, which have been published on ArcGIS Online. This application enables users to display 3D models for particular regions and time periods, and to overlay these models with PLATEAU 3D models. The application also features the ability to share viewpoints via URL. Presently, 3D models for 54 regions and time periods are available for viewing.

In the future, it is planned to create 3D models at a rate of several regions per year. In addition, attempts are being made to facilitate broader participation in this 3D visualization of past landscapes, including through hands-on seminars. The goal is to expand the target regions and time periods in a sustainable manner.

This report presents a field excursion conducted on August 26, 2024, focusing on historical materials and sites related to Nagakubo Sekisui (1717-1801), a geographer of the Edo period. Participants examined original editions of the Kaisei nihon yochi rotei zenzu (commonly known as the “Sekisui Map”) and related materials, which are compiled maps that circulated in Japan, with several copies also found overseas. The excursion also included visits to key local sites such as the Takahagi City Folk Historical Museum, Sekisui’s former residence, and his grave. Through on-site explanations and discussions, the participants deepened their understanding of the historical significance of Nagakubo Sekisui and his maps, particularly their educational value and the ongoing efforts for dissemination and educational outreach.