FROM TAPE TO SPACE – Fundamentals of spatial measuring: Part 2 – Units

1.1          Metric Units

Most common and standard unit is the metric unit system, where the base unit is meters (abbreviation “m”) according to SI definitions. Meter is defined as “Length travelled by light in  of a second”.

Few common breeds of meter are:

• Kilometer (km)     = 1000 m
• Centimeter (mm) =  m
• Millimeter (mm)  =  m

The practical smallest unit which can measured using a simple tape or ruler is millimeters. Beyond that will require special measuring devices like micrometer screw gauge, etc. Therefore, for the purpose of architectural presentation drawings, measuring architectural work, millimeters will be used to express dimensions in most of the situations.

1.2          Imperial Units

In Sri Lanka, however, some traditional masons, carpenters still rely on the old imperial measurement system (i.e. feet and inches). This is mainly because it is easier to visualize since the measuring system is based on things that make sense (Foot). However, the main disadvantage of this unit system is that there is no proper definition for the unit where definitions differ from country to country. Therefore, using this unit for overseas projects will create problems on expressing dimensions. However, according to the metric system, the foot is defined as follows:

1 Foot     = 0.3048 m (Symbol – Single Quote “‘”)

1 Inch     =  Foot (Symbol – Double Quote “””)

The practical smallest unit which can be measured by a ruler is  inch or sometimes  inch. However, most common smallest imperial unit used in construction is  of an inch and is identified in Sinhalese as “නූල”.

Figure 1 – Standard divisions of an inch (Source: Wikipedia)