kSIST FprEN ISO 25178-71:2026

Geometrical product specifications (GPS) - Surface texture: Areal - Part 71: Software measurement standards (ISO/FDIS 25178‑71:2026)

ISO 25178-71:2017 defines Type S1 and Type S2 software measurement standards (etalons) for verifying the software of measuring instruments. It also defines the file format of Type S1 software measurement standards for the calibration of instruments for the measurement of surface texture by the areal method as defined in the areal surface texture chain of standards, chain link G.
NOTE       Throughout ISO 25178-71:2017, the term "softgauge" is used as a substitute for "software measurement standard Type S1".

Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Flächenhaft – Teil 71: Software-Normale (ISO/FDIS 25178‑71:2026)

Dieses Dokument legt Software-Normale vom Typ S1, Referenzdaten, und Software-Normale vom Typ S2, Referenzsoftware, zur Verifikation der Software von Messinstrumenten fest. Es legt außerdem das SDF-Dateiformat der Software-Normale vom Typ S1 zur Kalibrierung von Messgeräten zur profil- und flächenhaften Messung der Oberflächenbeschaffenheit fest, wie sie für die Kettenglieder F und G der Normenkette über die Oberflächenbeschaffenheit festgelegt sind.
Das SDF-Dateiformat ist anwendbar auf profil- und flächenhafte Topographie-Messdaten, die mithilfe eines orthogonalen Gitters (siehe ISO 14406:2010, 5.2) und äquidistanten Abtastintervallen extrahiert wurden, unabhängig vom Messprinzip.
ANMERKUNG   In diesem Dokument werden durchgehend die Begriffe „Referenzdaten“ und „Referenz-Software“ als Ersatz für den Begriff „Software-Normal vom Typ S1 bzw. Typ S2“ verwendet. In der Praxis werden „Referenzdaten“ bisweilen als „Software-Normal“ oder „Software-Lehre“ bezeichnet.

Spécification géométrique des produits (GPS) - État de surface: Surfacique - Partie 71: Étalons logiciels (ISO/FDIS 25178‑71:2026)

L'ISO 25178-71:2017 définit les étalons logiciels de Types S1 et S2 qui permettent de vérifier les logiciels des instruments de mesure. Il définit également le format de fichier des étalons logiciels de Type S1 utilisés pour l'étalonnage des instruments de mesure d'état de surface, conformément à la méthode surfacique telle que définie dans le maillon G de la chaîne de normes sur l'état de surface surfacique.
NOTE       Dans l'ISO 25178-71:2017, le terme «étalon logiciel» désigne un «étalon logiciel de Type S1».

Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: Ravna - 71. del: Standardi za merilno programsko opremo (ISO/FDIS 25178‑71:2026)

General Information

• Status: Not Published
• Public Enquiry End Date: 09-Oct-2025
• ICS: 17.040.20 - Properties of surfaces
• ICS: 17.040.40 - Geometrical Product Specification (GPS)
• ICS: 35.080 - Software
• Technical Committee: ISEL - Mechanical elements
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 02-Jun-2026
• Due Date: 21-Jul-2026
• Ref Project: FprEN ISO 25178-71 - Geometrical product specifications (GPS) - Surface texture: Areal - Part 71: Surface data file (SDF) file format (ISO/FDIS 25178‑71:2026)

Relations

• Revises: SIST EN ISO 25178-71:2017 - Geometrical product specifications (GPS) - Surface texture: Areal - Part 71: Software measurement standards (ISO 25178-71:2017)
• Effective Date: 17-Jan-2024

Overview

kSIST FprEN ISO 25178-71:2026 specifies requirements for software measurement standards as part of the Geometrical Product Specifications (GPS) series for areal surface texture. This standard, developed by SIST and aligned with ISO/FDIS 25178-71, focuses on software verification in surface texture measurement. It defines two key types of software measurement standards-Type S1 (softgauges) and Type S2 (reference software)-and sets the file format for Type S1 softgauges using the Surface Data File (SDF) format. The purpose is to ensure that software used in measuring instruments for areal surface texture provides accurate and traceable results according to recognized international methods.

Key Topics

• Type S1 and Type S2 Software Standards

  • Type S1 (Softgauges): Digital reference data sets used to verify the performance of measurement software by inputting known data and comparing outputs to certified values.
  • Type S2 (Reference Software): Traceable computer programs that serve as benchmarks for assessing measurement software accuracy.

• Surface Data File (SDF) Format

  • Standardized file format for exchanging and calibrating areal surface measurement data.
  • Supports ASCII and binary representations with specific fields for metadata, data matrices, and historical records.
  • Enables unambiguous communication of measurement data between metrology instruments and software.

• Certification and Traceability

  • Requirements for calibration certificates to accompany each software measurement standard, including supplier information, traceable values, and measurement uncertainties.
  • Detailed marking and documentation to ensure traceability within the areal surface texture chain of standards.

• Data Compatibility and Integrity

  • Guidelines for handling missing or invalid data points in data matrices.
  • Use of versioning and file structure to maintain compatibility with evolving software and measurement technologies.

Applications

This standard has practical value in industries and laboratories where surface texture measurement and validation are essential for product quality and compliance. Typical applications include:

• Calibration of Areal Surface Measurement Instruments

  • Verification of instrument software before deployment or after updates.
  • Ensures consistency between different types or brands of instruments.

• Quality Assurance and Metrology Software Development

  • Development and testing of algorithms for surface texture analysis.
  • Software benchmarking using standardized softgauges and reference data.

• Accredited Testing and Certification

  • Provides a recognized framework for laboratory accreditation and certification of measurement processes.
  • Useful in audits and as a basis for demonstrating software measurement traceability.

• Research and Industrial Measurement Chains

  • Supports technological innovation by enabling reliable metrology software tools for advanced manufacturing and engineering applications.

Related Standards

For full compliance and efficient application, this standard should be used in conjunction with the following international standards and guides:

• ISO 25178 Series: The foundational chain of standards for areal surface texture measurement.
• ISO 14638: GPS matrix model providing the structure of the GPS system.
• ISO 8015: General GPS rules, including default decision criteria.
• ISO 14253-1: Decision rules for verification of conformity.
• ISO/IEC Guide 99: International vocabulary of metrology.
• ISO/IEC 10646: Character encoding standards for ASCII/UTF-8.

By following kSIST FprEN ISO 25178-71:2026, industries benefit from standardized, traceable, and interoperable software measurement approaches, ensuring accurate surface texture evaluation and supporting global quality requirements in manufacturing and engineering.

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN ISO 25178-71:2025
01-oktober-2025
Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: Ravna - 71.
del: Standardi za merilno programsko opremo (ISO/DIS 25178-71:2025)
Geometrical product specifications (GPS) - Surface texture: Areal - Part 71: Software
measurement standards (ISO/DIS 25178-71:2025)
Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Flächenhaft –
Teil 71: Software-Normale (ISO/DIS 25178-71:2025)
Spécification géométrique des produits (GPS) - État de surface: Surfacique - Partie 71:
Étalons logiciels (ISO/DIS 25178-71:2025)
Ta slovenski standard je istoveten z: prEN ISO 25178-71
ICS:
17.040.20 Lastnosti površin Properties of surfaces
17.040.40 Specifikacija geometrijskih Geometrical Product
veličin izdelka (GPS) Specification (GPS)
35.080 Programska oprema Software
oSIST prEN ISO 25178-71:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 25178-71:2025
oSIST prEN ISO 25178-71:2025
DRAFT
International
Standard
ISO/DIS 25178-71
ISO/TC 213
Geometrical product specifications
Secretariat: BSI
(GPS) — Surface texture: Areal —
Voting begins on:
Part 71: 2025-06-02
Software measurement standards
Voting terminates on:
2025-08-25
Spécification géométrique des produits (GPS) — État de surface:
Surfacique —
Partie 71: Étalons logiciels
ICS: 17.040.20; 17.040.40
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 25178-71:2025(en)
oSIST prEN ISO 25178-71:2025
DRAFT
ISO/DIS 25178-71:2025(en)
International
Standard
ISO/DIS 25178-71
ISO/TC 213
Geometrical product specifications
Secretariat: BSI
(GPS) — Surface texture: Areal —
Voting begins on:
Part 71:
Software measurement standards
Voting terminates on:
Spécification géométrique des produits (GPS) — État de surface:
Surfacique —
Partie 71: Étalons logiciels
ICS: 17.040.20; 17.040.40
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 25178-71:2025(en)
ii
oSIST prEN ISO 25178-71:2025
ISO/DIS 25178-71:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Type S software measurement standards . 4
4.1 General .4
4.2 Type S1, reference data .4
4.3 Type S2, reference software .4
5 File format for Type S1 reference data . 4
5.1 General .4
5.2 Record 1 — Header .5
5.2.1 General .5
5.2.2 Version number .5
5.2.3 Measurement instrument manufacturer's identifier .5
5.2.4 Original creation date and time .5
5.2.5 Last modification date and time.5
5.2.6 Number of columns in the data matrix, N .5
5.2.7 Number of rows in the data matrix, M .5
5.2.8 X-scale factor .5
5.2.9 Y-scale factor .5
5.2.10 Z-scale factor . .6
5.2.11 Z-resolution .6
5.2.12 Compression type .6
5.2.13 Data type .6
5.2.14 Checksum type . .6
5.2.15 Header description .6
5.3 Record 2 — Data area .7
5.3.1 General .7
5.3.2 Handling of non-measured or spurious points . .8
5.4 Record 3 — Trailer .8
6 Software measurement standard certificate . 9
Annex A (normative) ASCII and binary representation of the SDF format .10
Annex B (informative) Relation to the GPS matrix model .12
Bibliography .13

iii
oSIST prEN ISO 25178-71:2025
ISO/DIS 25178-71:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product
specifications and verification.
This third edition cancels and replaces the second edition (ISO 25178-71:2017), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the version number 2.0 has been added, which incorporates a number of new functionalities;
— in version number 2.0, the number of columns and the number of rows of the data matrix is represented
as a 4-byte unsigned integer instead of a 2-byte unsigned integer;
— in version number 2.0, two additional data types are available for data storage: a 1-byte signed integer
and a 4-byte floating point.
A list of all parts in the ISO 25178 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
oSIST prEN ISO 25178-71:2025
ISO/DIS 25178-71:2025(en)
Introduction
This document is a geometrical product specification standard and is to be regarded as a general GPS
standard (see ISO 14638). It influences the chain link F and chain link G of the chains of standards on profile
and areal surface texture.
The ISO GPS matrix model given in ISO 14638 gives an overview of the ISO GPS system of which this document
is a part. The fundamental rules of ISO GPS given in ISO 8015 apply to this document and the default decision
rules given in ISO 14253-1 apply to the specifications made in accordance with this document, unless
otherwise indicated.
For more detailed information of the relation of this document to the GPS matrix model, see Annex B.
This document is concerned with software gauges (Type S1) and reference software (Type S2). It defines the
surface data file (SDF) format for Type S1 software gauges.
The SDF format is already used by the industry, in particular, by instrument manufacturers and academia.
The basic concept of the SDF format was originally developed for tactile measuring instruments as part of
[8]
the European Surfstand project and EUR 15178 .

v
oSIST prEN ISO 25178-71:2025
oSIST prEN ISO 25178-71:2025
DRAFT International Standard ISO/DIS 25178-71:2025(en)
Geometrical product specifications (GPS) — Surface
texture: Areal —
Part 71:
Software measurement standards
1 Scope
This document specifies Type S1 and Type S2 software measurement standards for verifying the software of
measuring instruments. It also specifies the surface data file (SDF) format of Type S1 software measurement
standards for the calibration of instruments for the measurement of surface texture by the areal method as
defined in the areal surface texture chain of standards, chain link G. The SDF format is suitable for areal
topography measurement data extracted with an orthogonal grid (see ISO 14406:2010, 5.2) and equidistant
sampling intervals, regardless of the measurement principle.
NOTE Throughout this document, the term “softgauge” is used as a substitute for “software measurement
standard Type S1”.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC Guide 99, and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
software measurement standard
reference data or reference software intended to reproduce the value of a measurand with known
specification uncertainty in order to verify the software used to calculate the value of a measurand
3.2
ASCII
7-bit character encoding which is congruent with UTF-8 encoding in the first 128 characters
Note 1 to entry: See ISO/IEC 10646.
3.3
uint8
1-byte (8-bit) representation of an unsigned integer
Note 1 to entry: The value range of ”uint8” is from 0 to 255 .

oSIST prEN ISO 25178-71:2025
ISO/DIS 25178-71:2025(en)
Note 2 to entry: In version number 1.0 of the SDF format, the term BYTE was used instead of uint8.
3.4
int8
1-byte (8-bit) representation of a signed integer
Note 1 to entry: The value range of “int8” is from −128 to 127.
3.5
uint16
2-byte representation of an unsigned integer
Note 1 to entry: The value range of “uint16” is from 0 to 65 535.
Note 2 to entry: The least significant byte shall be stored first in the lowest memory address, which is known as the
[9]
“little endian” concept .
3.6
int16
2-byte representation of a signed integer
Note 1 to entry: The value range of “int16” is from −32 768 to 35 767.
Note 2 to entry: The least significant byte shall be stored first in the lowest memory address, which is known as the
[9]
“little endian” concept .
3.7
uint32
4-byte representation of an unsigned integer
Note 1 to entry: The value range of “uint32” is from 0 to 4 294 967 295.
Note 2 to entry: The least significant byte shall be stored first in the lowest memory address, which is known as the
[9]
“little endian” concept .
3.8
int32
4-byte representation of a signed integer
Note 1 to entry: The value range of “int32” is from −2 147 483 648 to 2 147 483 647.
Note 2 to entry: The least significant byte shall be stored first in the lowest memory address, which is known as the
[9]
“little endian” concept .
3.9
binary32
4-byte single precision representation of a normalized floating point number according to IEEE 754
38 38
Note 1 to entry: The value range of “binary32” is from −×3,402 823466 10 to 3,402 823466×10 .
Note 2 to entry: The least significant byte shall be stored first in the lowest memory address, which is known as the
[9]
“little endian” concept .
Note 3 to entry: Many programming languages support the 4-byte single precision representation in accordance with
IEEE 754. However, alternative terms are often used instead of “binary32”. For example, “float” in C and C++.
Note 4 to entry: The ASCII representation of a “binary32” number not equal to zero, see Figure 1, shall be a normalized
signed floating point number in scientific notation with 7 significant digits and a signed two digit exponent in the
range from −38 to +38. If the “binary32” number is equal to zero, the format “0.000000e+00” shall be used.

oSIST prEN ISO 25178-71:2025
ISO/DIS 25178-71:2025(en)
Key
A
sign for the fraction (“+ ” is optional)
B floating point number in the range [1,0: 10,0] with one digit before and 6 digits after the decimal point
C symbol for the exponent (“e” or “E”)
D
sign for the exponent (“+ ” or “− “ is mandatory)
E integer number in the range [0: 38]
Figure 1 — ASCII representation of “binary32” number

3.10
binary64
8-byte double precision representation of a normalized floating point number according to IEEE 754
Note 1 to entry: The value range of “binary64” is from −×1,797 693  134862315 810 to
1,797 693  134862315 ×810 .
Note 2 to entry: The least significant byte shall be stored first in the lowest memory address, which is known as the
[9]
“little endian” concept .
Note 3 to entry: In version number 1.0 of the SDF format, the term “DOUBLE” was used instead of “binary64”.
Note 4 to entry: Many programming languages support the 8-byte double precision representation in accordance with
IEEE 754. However, alternative terms are often used instead of “binary64”. For example, “double” in C and C++.
Note 5 to entry: The ASCII representation of a “bi
...