Chapter 31 Section 1 Viewing China from the World

After finishing the description of the history of ancient Chinese map surveying and mapping, it is necessary to review the history of cartography in the world, especially in the West, so that we can correctly understand the status of Chinese cartography achievements in the world. The founder of Western cartography is currently known to be Eratosthenes of Greece (276-196 BC). The production is decades to more than 100 years later.He determined the curvature of the Earth, and the solstice sundial (gui ghost) shadow measurements in Siena (present-day Aswan) and Alexandria enabled him to calculate the circumference of the Earth as 25,000 geographical miles.Greek cartography is based on spherical ground, which is different from Chinese cartography, which is based on flat ground, but in practice the difference between the two is not great, because the Greeks never invented a satisfactory projection method to project a spherical surface onto a flat sheet of paper.

The human world drawn by Eratosthenes is elliptical, 76,000 line-of-sight feet long (about 7,800 geographic miles), and 38,000 line-of-sight feet between north and south.A series of parallel lines (latitude lines) and meridians are distributed vertically and horizontally on it; the latitude lines are selected according to the length of the sundial shadow of the summer solstice and winter solstice, while the meridian lines are selected arbitrarily.The basic parallel is called the Rhodes line. It starts from Sanja in western Spain, connects Sicily and the tip of Greece, passes through Rhodes, and goes eastward along the southern edge of Mount Taurus.The cardinal meridian, which passes through Siena, Alexandria, Rhodes, and Byzantium, is even more incorrect than the cardinal parallel, which is thought to lie exactly on the Tropic of Cancer; the other meridian passes through Carthage, Sicily, and Rome.Both these latitudes and meridians differ greatly from the actual geographical location of the said place, and the meridian has a greater error than the latitude.The distance between these meridians, which cannot be measured except by reckoning from the ship's odometer and compass, resulted in an increase in the length of the Mediterranean Sea of ​​about one-fifth of its actual length.

The age of Yibagu's activities is roughly equivalent to Liu An, the author of "Huainanzi", and slightly later than the production age of "Mawangdui Han Tomb Map". He criticized and improved Eratosthenes' work, including using The term "zone" was introduced to denote the area between parallels of latitude.He replaced the arbitrarily determined latitudes of Esperanza with equal ones and fixed them astronomically.He identified 11 latitude lines in inhabited places, the southernmost one is located in the middle of the equator and the Tropic of Cancer, the next one is located at the place where the day length of the summer solstice is 13 hours, and one is extended every half hour thereafter, and the northernmost one passes through Northern Britain, where the day length on the summer solstice is 19 hours.Hipparcos made no improvements on the meridians.

By the time of Ptolemy (equivalent to the late Eastern Han Dynasty in China, about 300 years later than the "Mawangdui Han Tomb Map"), ancient Western scientific cartography reached its peak.Six of Ptolemy's eight-volume "Geography" are tables of latitude and longitude for specific locations, with an accuracy of 1/12 degrees, but the determination of longitude is based on speculation rather than actual measurement. condition.Nevertheless, Ptolemy greatly shortened the length of Asia (the distance from the stone tower to the Chinese capital) estimated by Marinus, and it turned out that Tolemy's calculation was correct.The largest map drawn by Tuo included 180° longitude and 80° latitude. He tried to draw both meridians and latitudes as curved lines in order to express the curvature of the earth's surface more accurately, but due to the The accuracy of the data is poor, and the actual effect is not good.It is worth noting that Ptolemy was particularly interested in understanding the geography of the East, and he used the materials provided by a Syrian, Mayas Tessianus, who had long traded silk with the Chinese.

Regrettably, none of the maps drawn in the Ptolemy era have been handed down.The earliest known restoration of a Ptolemy map was made by the Venetian Ross Sanli in 1561 according to speculation.The maps mentioned in many manuscripts are attributed to Agatho Damon of Alexandria, but the date of his birth and death is unknown, between the 2nd and 13th centuries AD.The only other ancient map that survives is a very inaccurate map of the roads of the Roman Empire discovered by Konrad Puttinger in 1507, now commonly known as the Putinger map, which was made by a Colmar The monk drew it from an unknown document, and the original picture was probably drawn between 20 and 370 AD, which roughly corresponds to the period from the Eastern Han Dynasty to the middle Eastern Jin Dynasty in China.Although this map is marked with mileage, it is still diagrammatic and cannot be compared with "Fangmatan Map".

After Ptolemy, there was a major break in European cartography. Scientific cartography was completely replaced by the cartographic tradition of religious cosmology. The attempt to use coordinates was abandoned, and the world was drawn as a disk divided into several Partially to represent several continents, with many rivers and mountains scattered in a haphazard manner.There are quite a few such maps, which are generally called wheel maps or "T-○ maps", and most of them appear as drawings in medieval works.The earliest known wheel-shaped map can be found in "Scipio's Dream" written by Macrovius (395-423 AD), and the earliest handed down one was made in 970 (corresponding to the early Northern Song Dynasty). The last one was made in 1250 (the tenth year of Chunyou in the Southern Song Dynasty).There are roughly three forms of this type of map: the earliest one is called the Marcorovian type, which still retains a view of Ptolemy, that is, the southern hemisphere of the world below the equator is regarded as an unknown continent, but only Use a letter T to represent the "inhabited world". The vertical part of the T letter is the Mediterranean Sea, and the two halves of the horizontal letter are the Don River and the Nile River.Jerusalem, if present on the map, is always drawn in the center of the circle.The Libanensis-style world map that appeared later simply omitted the unknown continents in the southern hemisphere, and let the "inhabited world" occupy the entire disk.The third form vaguely preserves the regions mentioned in the Greek era, but neither the meridian nor any geographical indications are drawn in the picture, and only some parallel lines are used to indicate these regions.

Leonardo Dadi (1365-1424 A.D.) wrote in a poem titled "Las Ferro" around 1420 (the eighteenth year of Ming Yongle): The word T is made in the circle, which divides the world into three.The upper part is Asia, which occupies nearly half of the world. The lower vertical is the boundary, two and three are divided.Two euros and three non-xi, the Mediterranean is in between. This can be regarded as a classic interpretation of the T-O universe map, that is: to make a T in an O, divide the world into three.The upper part of the circle is Asia, which occupies almost half of the world. The vertical line of the T divides the lower half of the circle into two parts, of which two-fifths are Europe, three-fifths are Africa, and the Mediterranean Sea is located between Europe and Africa. The tradition of the TO universe map did not disappear until the end of the 17th century, which shows the great impact of this interruption.

Around 1300, a kind of nautical chart drawn for practical purposes began to appear in the Mediterranean area. The outline of the European continent was mainly drawn in the picture, and the names of ports and coastal cities were marked on its edges, and some pictures were usually added. national flag to indicate which country they belong to.The earliest nautical chart that can be dated is the nautical chart drawn by Visconte in 1311 (one said 1281), and there have been more and more nautical charts since then, and many publications containing such nautical charts can still be seen now.The practical nautical chart does not draw lines of latitude and longitude, nor does it draw a rectangular grid, but a kind of interlaced compass bearing lines or oblique lines. The compass bearing lines extending in all directions from the center.The method of drawing is that the helmsman selects a diagonal sailing line near the two ports or near the start and end of the day's voyage, so that the straight line connecting the two ports or the two points as directly as possible is parallel.With these slashes, the required navigation bearing can be easily read out.

The Renaissance also had a huge impact on cartography, and Ptolemy's geographical knowledge was revived.And the increasing understanding of East Asian geography led to an upsurge in drawing world maps in Europe.The Ptolemaic coordinate system, which had been inexhaustible only in the Greek-speaking areas, was finally revived, and Prince Henry of Portugal, famous for organizing several famous expeditions, played an important role.By 1475, Ptolemaic cartography had regained dominance in cartography.Glaud Mercator (1512-1594 A.D.) drew a large map of the world in 1538 (the 17th year of Jiajing in the Ming Dynasty) using the cylindrical conformal projection method. Then, Waghner's "Seafarer's Treasure Book" and Austrian Proxy maps came out one after another in 1584 (the 12th year of Wanli in Ming Dynasty), marking the entry of cartography into the modern era.

Therefore, in general, the theory and practice of early western cartography were not as advanced as those in China. Eratosthenes and Ptolemy were later than the "Fangmatan Map" and "Mawangdui Han Tomb Map" respectively. And there is no real map left.But we should also admit that early Chinese cartography focused on actual surveying and mapping. The recorded and existing objects are generally limited to the country and the local area. Pei Xiu, who was later than Ptolemy, also summarized the drawing of maps. specific theory.In contrast, Western cartographers pay more attention to geographical knowledge beyond their own country and locality, and pay more attention to the induction and elaboration of macro theories.In the great interruption period after Ptolemy, the development of cartography in China has never been interrupted, so it is far ahead of the West.It was not until the late 16th century that Western modern cartography showed its advantages.However, China's long tradition of cartography, rich accumulation of geographical knowledge, and vast and unified land have enabled the advanced western cartography theories and methods to be fully practiced for the first time, and also made Chinese cartography in the early 18th century come to the forefront of the world again. .It is a pity that this advantage did not last long. While Western cartography was making progress, China stuck to the old rules, and even retreated from the science and technology it had mastered, and finally fell behind the world.