The map is made of hundreds of individual sheets of ruled paper panels. It is twenty-two panels wide and twenty-nine panels high.
The height of each panel represents a unit measure of 100 Korean ri, and the width of each panel represents a unit measure of seventy Korean ri. One Korean ri is equivalent to 400 meters (0.4 kilometers).
The scale of the map is about 1/216,000th of actual size.
Each panel has a 10-segment rule for the height and a 7-segment rule for the width. Each segment represents a distance of ten ri. Two panels are used to rpresent Ulleungdo (鬱陵島) and its neighboring island of Usan (于山 - 우산).
The above panel shows the west coast of Ulleungdo.
The above panel shows the east coast of Ulleungdo.
Notice that the small island off the east coast of Ulleungdo is labeled "Usan" (于山), which is an abbreviation of Usando (于山島 - 우산도). The map shows Usando to be about ten ri off of Ulleungdo's east shore since there is about one segment distance between Ulleungdo and Usan. Ten ri would be about four kilometers, which means that the Usan on the map was almost certainly Ulleungdo's neighboring island of Jukdo (竹島 - 죽도), which is about 2.2 kilometers off Ulleungdo's east shore. The writing below Usan translates as follows:
“In the 11th year of Yeongjo (1735), Gangwon Provincial Governor Jo Choi-suKoreans usually claim that Usando was the old name for present-day "Dokdo" (Liancourt Rocks), but the above map clearly shows that Usando was the old name for Ulleungdo's neighboring island of Jukdo, which is about 2.2 kilometers off of Ulleungdo's east shore.
reported to the king: ‘A survey of Ulleungdo has found that the land is wide and
fertile, and there are signs that people once lived there. Also, to its west is
Usando, which is also wide and spacious.’ The so-called “west” character is
different on this map, where (Usando) is to the east.
The following graphic shows that the Usan on the above map was almost certainly Ulleungdo's neighboring island of Jukdo (竹島), not Dokdo (Liancourt Rocks), which the Japanese presently refer to as Takeshima (竹島). The fact that Koreans use the same Chinese characters to refer to Ulleungdo's neighboring island of Jukdo as the Japanese use to refer to Takeshima (Liancourt Rocks) may be part of the reason for the present-day confusion.
The Cheonggudo is currently located at Seoul National University's Kyujanggak (규장각) Museum. Here is a link to the museum's Web site, which is excellent: