Chapter 14 Section 2 Jia Dan and his "Hai Nei Hua Yi Tu"

Jia Dan (729-805 A.D.), courtesy name Dunshi, was named Wei Guogong during his lifetime, and later known as Jia Weigong; he was born in Nanpi County, Cangzhou (now Nanpi County, Hebei Province), and he was another one after Pei Xiu. A great cartographer. Jia Dan started his official career at the age of 30. At first, he was only a Jiupin county lieutenant. At the age of 50, he was promoted to Hongluqing.His main responsibility is to receive foreign guests, so he has the opportunity to "understand the feelings of barbarians and Didi" and obtain a lot of first-hand information about the four frontiers and foreign countries.In the ninth year of Zhenyuan (793 A.D.), Jia Dan became prime minister at the age of 64 until his death at the age of 76.Jia Dan did not do much in politics, but his achievements in geography and cartography were quite outstanding. He was in a high position, and he was able to master and use a large amount of important geographical data. Practical ambition and excellent knowledge of geography.

In the 14th year of Zhenyuan (AD 798), Jia Dan, based on the long-term accumulation of materials, drew a one-axis map of "Guanzhong Longyou and Shannan Kyushu" and dedicated it to Tang Dezong for him to understand the geography of the Longyou area that has been lost in Tubo for many years. situation.In order to make up for the lack of picture content, there are also six volumes of "Bie Lu" and four volumes of "Tubo Yellow River Record" in the nature of notes.In the table offering the map, Jia Dan mentioned the cartographic theory that "Jin Sikong and Pei Xiu created six bodies", calling it "the new idea of ​​the map", and said that "although the minister is ignorant, he has been a teacher for a long time" (although I am ignorant , but I have been studying the six-body cartography for a long time, and use it as an example), it can be seen that this map is drawn according to the six-body cartography.

Before completing this map, Jia Dan had a plan to draw a national map. After ten years of hard work, he finally completed the "Hainei Huayi Map" and used it as a text in the 17th year of Zhenyuan (801 A.D.) when he was 72 years old. The appendix is ​​40 volumes of "Ancient and Modern County, Country, County, and Road Siyi".It can be seen from the table in which he presented the map that as early as the first year of Xingyuan (784 AD), he accepted the emperor's order to compile the "National Map". It was only then that I was able to concentrate on map compilation, which lasted nearly 30 years.This large map drawn by craftsmen is three feet wide and three feet long. The scale is "one inch is converted into a hundred miles" (about 1:150,000), which distinguishes the Central Plains and "Zuojia" (minority) areas , showing the direction of the mountains and the source of the rivers.Calculating on a scale, the map covers 30,000 miles from east to west and more than 30,000 miles from north to south.Although the text does not specify the age of the picture, but from the "Ancient and Modern County, County, Road and Siyi Shu" "China is headed by "Yu Gong", and the foreign barbarians are originated from "Ban Shi"", the Central Plains drawn on the picture The upper limit of the content is the era of "Yu Gong", and the upper limit of the surrounding area is the "Han Shu·Geographic Records", which is a historical map from the pre-Qin period to the beginning of the 9th century.

In this map, Jia Dan pioneered a method of using different colors to depict different ancient and modern place names for comparison, that is, "the ancient place names are inscribed with ink (black), and today's prefectures and counties are inscribed with vermilion (red)".This method of "ancient ink and modern Zhu" (annotate the ancient content in black and the current content in red) was pioneered by Jia Dan. Because of its advantages of being easy to compare and clear at a glance, it is especially suitable for Chinese historical maps with frequent changes in ancient and modern place names. , has been used ever since.Yang Shoujing still used this method when he drew the Maps of Past Dynasties and Zhutu of Water Classics in the late Qing Dynasty and the early Republic of China. The eight-volume Atlas of Chinese History published in 1982 and edited by Professor Tan Qixiang (Xiang Xiang) also inherited this method. A tradition, all pictures have a contrast between ancient and modern.

Such a huge map is of course difficult to preserve, so it has not been handed down.However, the "Huayi Map" (Fig. 11), which is carved in stone in 1136 (the seventh year of Fuchang in Liuyu) and is now in the Forest of Steles in Xi'an, is engraved: "The land of the barbarians in all directions, all the numbers recorded in the official map of Jiawei in Tang Dynasty Hundreds of countries, today are written by those who have heard about it.” It can be seen that there may have been copies or compendiums of the "Huayi Map in China" at that time, so the "Huayi Map" can reflect the appearance of Jia Dan's original map to a certain extent. .