The standards on Geometrical Product Specifications (GPS) have been developed by different ISO Technical Committees and only when there was a strong demand for them. Therefore in the field of GPS some standards are still missing or incomplete.

ISO has now combined the former ISO Committees into a new ISO Committee on GPS and verification (ISO TC 213).

The tasks of ISO TC 213 are to identify gaps and, if existing, contradictions in the standards and to develop future harmonized standards.

Typical tasks of the group are standards on

• definition of actual size (e.g. of cylindrical features, conical features, features composed of two parallel planar surfaces);

• definition of actual distances (e.g. of actual axes, stepped surfaces);

• definition of actual radius;

• definition of actual derived features (actual axes, actual median faces);

• definition of filter requirements in order to distinguish between roughness, waviness, form, orientation and location, size and distance;

• identification of calibration requirements;

• requirements for measuring strategy and assessment of measurement uncertainties.

The ISO Technical Report ISO TR 14 638 GPS Masterplan explains the concept of GPS and provides a Masterplan of GPS including a list of the existing standards and the standards to be issued in this field.

The concept of GPS:

• covers several types of standard, some are dealing with the fundamental rules of specification (Fundamental GPS standards) (e.g. ISO 8015, Fundamental tolerancing principle), some are dealing with global principles and definitions (Global GPS standards) (e.g. ISO 1, Reference temperature), some are dealing directly with the geometrical...