Gnomon

圭表的主要功能是测定冬至日所在，并进而确定回归年
长度，此外，通过观测表影的变化可确定方向和节气。
Thank you！
谢谢！

The function
主要功能
The
main function of the program is to determine where the winter solstice, and then determine the tropical year length, in addition, by observing changes of shadow can determine the direction and solar term.
圭表直立于平地上测日影的标杆和石柱，叫做表；正 南正北方向平放的测定表影长度的刻板，叫做圭。当太阳 照着表的时候，圭上出现了表的影子，根据影子和方向和 长度，就能读出时间。

The history 圭表历史
Long ago, people find housing, trees and other objects will cast a shadow in the sun, the shadow of change has certain laws. So he stood in the ground on a pole or pillars to observe the change of the shadow, the vertical rod or a column called "table"; with a ruler measuring the length of the shadow and the direction,can know the time. Later, found that the noon of the shadow is always to the north direction, made of stone ruler spread on the ground, vertical and vertical surface, the ruler is connected to a base table, the other end to the north direction, which made with slate ruler is called "gui". Noon shadow cast in stone,the ancients can directly read the length of the shadow value taon
基本介绍

Gnomon standing upright on the ground to
measure the shadow of the bench marking and pillars, called table; due north direction determination of rigid flat surface shadow length, called gui. When the sun is shining table, the table of the shadow and the shadow, according to the direction and the length of time,you can read.

很早以前，人们发现房屋、树木等物在太阳光照射下会投出影子， 这些影子的变化有一定的规律。于是便在平地上直立一根竿子或石柱 来观察影子的变化，这根立竿或立柱就叫做“表”；用一把尺子测量 表影的长度和方向，则可知道时辰。后来，发现正午时的表影总是投 向正北方向，就把石板制成的尺子平铺在地面上，与立表垂直，尺子 的一头连着表基，另一头则伸向正北方向，这把用石板制成的尺子叫 “圭”。正午时表影投在石板上，古人就能直接读出表影的长度值。