Ino Tadataka (伊能 忠敬 February 11 1745 - May 17 1818) was a Japanese surveyor and cartographer. He is known for completing the first map of Japan created using modern surveying techniques.

Tadataka was born in a coastal village in Kazusa Province, in what is now Chiba Prefecture, and was adopted (aged seventeen) by the prosperous Ino family of Sawara, a town in Shimo-Usa Province. He ran the family business, expanding its sake brewing and rice-trading concerns, until he retired at the age of 49. At this time he moved to Edo and became a pupil of astronomer Takahashi Yoshitoki , from whom he learned Western astronomy, geography, and mathematics.

In 1800, after nearly five years of study, the Shogunate ordered Tadataka to perform a survey of the country. This task, which consumed the remaining seventeen years of his life, covered the entire coastline and some of the interior of each of the Japanese home islands. During this period Tadataka reportedly spent 3,736 days making measurements (and travelled 34,913 kilometres), stopping regularly to present the Shogun with maps reflecting his survey's progress. He produced a number of detailed maps (some at a scale of 1:36,000, others at 1:216,000) of select parts of Japan, mostly in Kyushu and Hokkaido. Tadataka's magnum opus, his 1:216,000 map of the entire coastline of Japan, remained unfinished at his death in 1818, but was completed by his surveying team in 1821. An atlas collecting all of his survey work, entitled Dai Nihon Enkai Yochi Zenzu (maps of Japan's coastal area), was published that year. It showed the entire country on eight pages at 1:216,000, 214 pages of select coastal areas at 1:36,000, and three pages of fine detail at 1:432,000. The Ino-zu (Ino's maps), many of which are accurate to 1/1000 th of a degree, remained the definative maps of Japan for nearly a century, and maps based on his work were in use as late as 1924.

In addition to his maps, Tadataka produced several scholarly works on surveying and mathematics, including Chikyu sokuenjutsu mondo and Kyukatsu en hassenho.

Tadataka is celebrated as one of the architects of modern Japan. A museum, dedicated to his memory, was opened in his former home in Sawara, and in 1996 was designed a National Historic Site. In November 1995 the Japanese government issued a commemorative 80 Yen postage stamp, showing Tadataka's portrait and a section of his map of Edo. Most of the complete copies of the atlas have been lost or destroyed (often by fire), although a mostly-complete copy of the large-scale map was discovered in the collection of the U.S. Library of Congress in 2001.

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• A photograph of the entire 1:216,000 coastal map