The ISO-GPS Language, a Proposed Interpretation of ISO 1101: 2017

Geometrical Product Specifications (GPS) is the international symbolic language used to express geometrical technical functional requirements in technical drawings and unambiguously to define their meaning by relying on precise concepts and symbolic representations. Facing some ambiguities produced by certain “open” interpretations in the geometric specification of products (GPS) justifies a critical study and the indication a few guidelines for graphic interpretation of some concepts. On the other hand, EN ISO 1101: 2017 is a functional dimensioning tool defined on isolated, rigid, and immobile parts (except for run-out specifications) that should express unambiguously and completely all the specifications per zone for the geometry of a product on a sufficient nominal model support for the understanding of the standard and corresponding to the functional requirements of its assembly context, to which the part belongs. These difficulties in the interpretation of the norm persist at present, as reported by companies in our industrial environment. This document suggests guidelines for the interpretation of some concepts of the EN ISO 1101: 2017 standard (for non-expert engineering students) and aims to apply a systematic sequential procedure set in a series of steps to provide the precise determination of the tolerance zone to avoid ambiguity, misconceptions, and to enable definition and representation of geometric specifications in technical drawings.