The choice of whether to use English or metric units for measurements and plotting can depend on a variety of circumstances.
If the available equipment is accurately calibrated and the measurers follow standard procedures, then data can be recorded in either English or metric units.
Many community clinics use English units, while most secondary and tertiary clinics and research projects prefer to use metric units.
The most important
factors are to develop reliable techniques, to use calibrated equipment,
and to perform accurate measurements.