section_path: Science and technology/Cartography, ships, and vehicles
section_name: Cartography, ships, and vehicles
paragraph_text: Cartography, ships, and vehicles
  
  Evidence found in Chinese literature, and archaeological evidence, show that cartography existed in China before the Han. Some of the earliest Han maps discovered were ink-penned silk maps found amongst the Mawangdui Silk Texts in a 2nd-century BC tomb. The general Ma Yuan created the world's first known raised-relief map from rice in the 1st century. This date could be revised if the tomb of Emperor Qin Shi Huang is excavated and the account in the Records of the Grand Historian concerning a model map of the empire is proven to be true.
  
  Although the use of the graduated scale and grid reference for maps was not thoroughly described until the published work of Pei Xiu (AD 224–271), there is evidence that in the early 2nd century, cartographer Zhang Heng was the first to use scales and grids for maps.
  
  Han dynasty Chinese sailed in a variety of ships different from those of previous eras, such as the tower ship. The junk design was developed and realized during the Han era. Junk ships featured a square-ended bow and stern, a flat-bottomed hull or carvel-shaped hull with no keel or sternpost, and solid transverse bulkheads in the place of structural ribs found in Western vessels. Moreover, Han ships were the first in the world to be steered using a rudder at the stern, in contrast to the simpler steering oar used for riverine transport, allowing them to sail on the high seas.
  
  Although ox-carts and chariots were previously used in China, the wheelbarrow was first used in Han China in the 1st century BC. Han artwork of horse-drawn chariots shows that the Warring-States-Era heavy wooden yoke placed around a horse's chest was replaced by the softer breast strap. Later, during the Northern Wei (386–534), the fully developed horse collar was invented.