In the late Edo period, Ino Tadataka embarked on a nationwide survey at the age of 55. His name is still widely known today as the creator of Japan’s first accurate map based on actual measurements. However, behind this remarkable achievement was the existence of surveying instruments that combined the cutting-edge technology of the time with Tadataka’s own ingenuity. Among these, the surveying wheel he used played an extremely important role in accurately recording Tadataka’s footsteps as he walked around the country conducting surveys.
In this article, we will focus on Ino Tadataka’s surveying wheel, unraveling the details of Edo-period surveying techniques and the instruments Tadataka developed and improved. We will also consider the social background of the time and the impact Tadataka’s surveys had on Japanese geography and navigation. Furthermore, we will explore the essence of Edo’s scientific technology while comparing it with modern GPS technology.
- Ino Tadataka’s Life and Path to Surveying
- Surveying Techniques in the Edo Period
- Ino Tadataka’s Surveying Wheel
- Other Surveying Instruments and Techniques
- The Reality and Hardships of Surveying
- Completion of the Ino Maps and Their Impact
- Comparison with Modern Technology
- The Legacy of Ino Tadataka
- Conclusion
Ino Tadataka’s Life and Path to Surveying
Portrait of Ino Tadataka, who embarked on a nationwide survey at the age of 55
Ino Tadataka was born in 1745 (Enkyō 2) in what is now Katori City, Chiba Prefecture. He worked for a merchant family from a young age and later became an adopted son-in-law, running a sake brewing business. However, after turning 50, he retired and devoted himself to scholarship. Tadataka, particularly interested in astronomy and calendar studies, went to Edo to study under Takahashi Yoshitoki.
It was during this period that Tadataka encountered surveying techniques. At that time, Japanese maps were mainly based on hearsay and speculation, lacking accuracy. Tadataka strongly felt the need for accurate maps based on actual measurements and decided to embark on the great endeavor of surveying the entire country at the age of 55.
Surveying Techniques in the Edo Period
By the late 18th to early 19th century when Tadataka began his surveys, Japanese surveying techniques had already developed to some extent. However, these were mainly used for local surveys and could not be applied to nationwide surveying.
The main surveying techniques of the time included:
- Kenzao (measuring rod): A method of measuring distance using bamboo or wooden rods of a fixed length
- Level: An instrument for measuring horizontal levels
- Compass: A device using magnets to determine direction
- Quadrant: An instrument for measuring the altitude of celestial bodies
While basing his work on these techniques, Tadataka needed to develop new methods and instruments suitable for nationwide surveying.
Ino Tadataka’s Surveying Wheel
A replica of the surveying wheel used by Ino Tadataka. It has a precise mechanism for accurately measuring distance based on wheel rotations. By Momotarou2012 – Own work, CC BY-SA 3.0, Link
One of the most notable surveying instruments developed and improved by Tadataka was the surveying wheel (ryōteisha). This was a device for measuring distance based on the number of wheel rotations, which Tadataka improved to achieve the accuracy and durability suitable for nationwide surveying.
Tadataka’s surveying wheel had the following characteristics:
a) Structure
The surveying wheel consisted of a large wheel about 1.5 meters in diameter with a gear mechanism incorporated. For each rotation of the wheel, it would advance a distance equal to its circumference.
b) Accuracy
It was marked with graduations every 1 ri (about 3.9 km), allowing for very accurate distance measurements. This level of precision was groundbreaking for its time.
c) Operability
The surveying wheel was pushed by a person, allowing for accurate distance measurements even on rough terrain or winding roads.
d) Durability
It was built to withstand long surveying journeys. Moreover, it was designed for easy part replacement, allowing for on-site repairs in case of malfunction.
Tadataka used this surveying wheel to accurately record the distances he walked, which formed the basis for his map creation. The surveying wheel was a crucial tool that supported the foundation of Tadataka’s surveying work.
Other Surveying Instruments and Techniques
In addition to the surveying wheel, Tadataka developed and improved various other surveying instruments. The main ones include:
a) Compass
The compass had a larger magnetic needle than conventional ones and finely engraved directional markings. It also featured improvements to reduce friction at the needle’s pivot point, enabling more accurate direction measurements. From “Ino Tadataka” by Ryōkichi Ōtani (1919), p.322.
Tadataka improved on existing compasses, creating ones with higher precision. This allowed for more accurate direction measurements.
b) Kiku (Protractor)
The kiku is an instrument for measuring angles. Tadataka improved its portability, making it more suitable for field use.
c) Celestial Observation Instruments
The quadrant used by Ino Tadataka. An indispensable precision instrument for measuring the altitude of celestial bodies and calculating latitude. テレストレラッソ, CC BY-SA 4.0, via Wikimedia Commons
Tadataka also used instruments such as quadrants and transit instruments to measure latitude through celestial observations. By measuring the altitude of stars with these instruments, he could calculate the latitude of a given location.
d) Triangulation Method
Tadataka also introduced the triangulation method. This method uses the properties of triangles to measure distances and positions, enabling more accurate surveying.
By combining these instruments and techniques, Tadataka achieved highly accurate surveys. In particular, his method of combining pedometry with celestial observations was unique to Tadataka and would go on to have a significant influence on subsequent Japanese surveying techniques.
The Reality and Hardships of Surveying
This surveying scene concretely illustrates the surveying techniques of the time. It is presumed that the survey team led by Ino Tadataka used similar methods in their great endeavor of creating a map of Japan.
Tadataka’s surveys were conducted over 17 years, from 1800 (Kansei 12) to 1816 (Bunka 13). During this period, Tadataka undertook 10 surveying journeys, traveling all around Japan.
The surveying procedure was generally as follows:
- Measure distance using the surveying wheel
- Confirm direction with a compass
- Measure angles of mountains and islands with a protractor
- Calculate latitude through celestial observations
- Create maps based on this data
This process was carried out along the coastlines and major roads throughout Japan.
Completion of the Ino Maps and Their Impact
The “Dai Nihon Enkai Yochi Zenzu” (Complete Coastal Map of Great Japan), also known as the Ino Maps, created based on Ino Tadataka’s survey results
The maps created based on Tadataka’s survey data are called “Ino Maps” and were highly regarded as Japan’s first accurate maps based on actual measurements. The Ino Maps were created in three versions: large-scale (1:36,000), medium-scale (1:216,000), and small-scale (1:432,000).
The completion of the Ino Maps had a significant impact on Japanese geography and navigation:
a) Contribution to Geography
The Ino Maps were far more accurate than previous maps based on imagination and speculation. This greatly advanced the understanding of Japanese geography and formed the basis for subsequent geographical research.
b) Development of Navigation
Accurate coastal maps greatly improved the safety of navigation. This led to more active maritime traffic in Japanese waters, contributing to the development of logistics and cultural exchange.
c) Utilization in Land Management
The shogunate used the Ino Maps for land management, enabling more efficient governance.
d) Influence on the West
The accuracy of the Ino Maps was highly appreciated by Western geographers as well. This led to international recognition of the high level of Japanese surveying techniques.
Comparison with Modern Technology
Modern surveying technology uses advanced methods such as GPS (Global Positioning System), laser rangefinders, and drones. Compared to these technologies, Tadataka’s surveying techniques might seem primitive.
However, surprisingly, the accuracy of the Ino Maps is not much inferior to modern maps. For example, when the small-scale Ino Map (1:432,000) is overlaid with a modern map, the error is said to be within about 1%. This is an astonishing level of accuracy considering the technological standards of the time.
The reasons why Tadataka’s surveying techniques achieved accuracy comparable to modern standards include:
- Careful adjustment and maintenance of high accuracy for instruments such as the surveying wheel and compass
- Use of celestial observations to confirm positions
- Careful recording of survey data and meticulous mapping
- Minimizing the accumulation of errors through long-term surveys
These points are fundamental concepts that apply to modern surveying techniques as well. Tadataka’s surveys were conducted using the highest technology of the time while adhering to these basic principles.
The Legacy of Ino Tadataka
Ino Tadataka’s surveying project not only created accurate maps but also greatly contributed to the development of Japanese science, technology, and scholarship. His legacy continues to be passed down in various forms to the present day:
a) Foundation of Surveying Techniques
Tadataka’s surveying methods became the foundation for subsequent Japanese surveying techniques. In particular, his method of combining pedometry with celestial observations remained the basis of Japanese surveying for a long time.
b) Spread of Scientific Spirit
Tadataka’s approach demonstrated the importance of scientific methods based on observation and actual measurement. This influenced the development of science and technology in Japan’s subsequent modernization.
c) Model for Lifelong Learning
Tadataka’s life, taking on a new field in his 50s and achieving great results, is still cited as a model for lifelong learning in modern times.
d) Contribution to Geographic Education
The Ino Maps are still used in geographic education today, serving as educational materials to deepen understanding of Japan’s territory.
Conclusion
The surveying techniques centered around Ino Tadataka’s surveying wheel represented the pinnacle of scientific technology in the Edo period. They were not mere tools, but the crystallization of Tadataka’s passion and ingenuity, as well as the wisdom produced by the society of that time.
Tadataka’s surveying project not only resulted in the creation of accurate Japanese maps but also had a significant impact on the development of Japanese science, technology, and scholarship. Its spirit continues to be passed down to us today as the foundation of modern surveying techniques, geography, and scientific thinking.
Even in an age of advanced modern surveying technologies such as GPS, looking back on Ino Tadataka’s achievements and the history of surveying techniques behind them can provide us with many insights. It reminds us of the importance not only of technological progress but also of the human passion and ingenuity that support it.
The path pioneered by Ino Tadataka and his surveying wheel still stretches out before us. As we trace this path, we too can move forward towards new discoveries and creations.
Ino Tadataka’s legacy continues in modern times. Statues and monuments erected across the country commemorate his achievements. By tak1701d – Own work, CC BY 3.0, Link
Ino Tadataka’s surveying techniques, centered around his surveying wheel, offer many insights to modern society. For example, his ingenuity in achieving maximum results with limited technology and his approach to tackling projects with a long-term perspective have parallels in today’s scientific and technological development and project management.
Moreover, Tadataka’s achievements can be utilized in geographic and local education. By studying the process of creating the Ino Maps, students can develop scientific thinking and curiosity. Furthermore, Tadataka’s lifelong learning attitude can serve as a role model for promoting lifelong education and social participation of the elderly.
In this way, Ino Tadataka’s achievements are not just historical events to be looked back upon, but can be used as a source of inspiration when tackling various challenges in modern society. It is important for us to inherit Tadataka’s spirit and continue to move forward towards new challenges.
