Ding Lan ruler is a geomantic tool. Measure the size of the Yin House, which is one foot, two inches and eight minutes long, and one foot is about 38.78 cm. Divided into ten squares, it is engraved with the cross of "wealth, mourning, wealth, death, official, righteousness, suffering, prosperity, harm and determination". It is more appropriate to use auspicious words.
1m =2.59 Ding Lan feet.