Rulers are etched with markings that denote the measurement of distance. Every inch of a 12-inch ruler is marked out, and between each inch, every 1/8 of an inch or 1/16 of an inch is marked. Likewise, a ruler of a similar length measuring centimetres will have each of 30 centimetres marked out. Holding your ruler against the thing you want to measure, for example, the side of a triangle, you can determine its length using the markings.

### Hatch Marks

"Hatch mark" is the name given to a mark on a ruler. Hatch marks are also known as hash marks. Hatch marks mark distance values on the ruler and notify you every unit of distance moved along a straight line.

### Hatching

On a ruler, there are a series of small vertical lines, separated at regular intervals, for example, millimetres. Every hatch mark that appears along that centimetre line will be at a distance of 1/10cm from the last. One 10th of a centimetre is a millimetre and each of the 10 millimetres within a centimetre is marked.

### Concepts of Hatching

Not all hatch marks on a ruler look the same, as some are longer and some are shorter. The longest on the inch ruler denotes the occurrence of one inch of distance along the line. The next longest are those that denote half-inches. The shortest of lines are the 1/8-inch or the 1/16-inch markings, depending on the ruler. Each hatch mark that represents an inch is numbered 1 to 12 on a 12-inch ruler. The shorter lines are not numbered, however, due to space restrictions.

### Scaling Hatches

Hatch marks are put on a map at the time of design for measurement of distance. They tell the reader how far landmarks are from each other. Hatching can be performed according to personal preference or best fit for purpose. For example, a map of a large area can have hatch marks that denote every mile of distance in a straight line. Along that line, between each mile, every half mile is marked. On a smaller map with more detail, hatching can be scaled more precisely. The mile markings along a line can now include 1/4 mile or 1/8 markings.