oSIST prEN ISO 25178-6:2026

Geometrical product specifications (GPS) - Surface texture: Areal - Part 6: Classification of methods for measuring surface topography (ISO/DIS 25178-6:2026)

ISO 25178-6:2010 describes a classification system for methods used primarily for the measurement of surface texture. It defines three classes of methods, illustrates the relationships between the classes, and briefly describes specific methods.

Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Flächenhaft - Teil 6: Klassifizierung von Methoden zur Messung der Oberflächentopographie (ISO/DIS 25178-6:2026)

Spécification géométrique des produits (GPS) - État de surface : Surfacique - Partie 6: Classification des méthodes de mesurage de la topographie de surface (ISO/DIS 25178-6:2026)

L'ISO 25178-6:2010 décrit un système de classification des méthodes employées principalement pour le mesurage de l'état de surface. Elle définit trois classes de méthodes, illustre la relation entre les classes et décrit brièvement les méthodes spécifiques.

Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: ploskovna - 6. del: Klasifikacija metod za merjenje topografije površine (ISO/DIS 25178-6:2026)

General Information

• Status: Not Published
• Public Enquiry End Date: 29-Apr-2026
• ICS: 01.040.17 - Metrology and measurement. Physical phenomena (Vocabularies)
• ICS: 17.040.20 - Properties of surfaces
• ICS: 17.040.40 - Geometrical Product Specification (GPS)
• Technical Committee: ISEL - Mechanical elements
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 05-Mar-2026
• Due Date: 23-Jul-2026
• Ref Project: prEN ISO 25178-6 - Geometrical product specifications (GPS) - Surface texture: Areal - Part 6: Classification of methods for measuring surface topography (ISO/DIS 25178-6:2026)

Relations

• Revises: SIST EN ISO 25178-6:2011 - Geometrical product specifications (GPS) - Surface texture: Areal - Part 6: Classification of methods for measuring surface texture (ISO 25178-6:2010)
• Effective Date: 25-Sep-2024

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2026
Specifikacija geometrijskih veličin izdelka (GPS) - Tekstura površine: ploskovna -
6. del: Klasifikacija metod za merjenje topografije površine (ISO/DIS 25178-6:2026)
Geometrical product specifications (GPS) - Surface texture: Areal - Part 6: Classification
of methods for measuring surface topography (ISO/DIS 25178-6:2026)
Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Flächenhaft -
Teil 6: Klassifizierung von Methoden zur Messung der Oberflächentopographie (ISO/DIS
25178-6:2026)
Spécification géométrique des produits (GPS) - État de surface : Surfacique - Partie 6:
Classification des méthodes de mesurage de la topographie de surface (ISO/DIS 25178-
6:2026)
Ta slovenski standard je istoveten z: prEN ISO 25178-6
ICS:
17.040.20 Lastnosti površin Properties of surfaces
17.040.40 Specifikacija geometrijskih Geometrical Product
veličin izdelka (GPS) Specification (GPS)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 25178-6
ISO/TC 213
Geometrical product specifications
Secretariat: BSI
(GPS) — Surface texture: Areal —
Voting begins on:
Part 6: 2026-02-27
Classification of methods for
Voting terminates on:
2026-05-22
measuring surface topography
Spécification géométrique des produits (GPS) — État de surface :
Surfacique —
Partie 6: Classification des méthodes de mesurage de la
topographie de surface
ICS: 17.040.20; 17.040.40; 01.040.17
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
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PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
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NOTIFICATION OF ANY RELEVANT PATENT
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PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 25178-6:2026(en)
DRAFT
ISO/DIS 25178-6:2026(en)
International
Standard
ISO/DIS 25178-6
ISO/TC 213
Geometrical product specifications
Secretariat: BSI
(GPS) — Surface texture: Areal —
Voting begins on:
Part 6:
Classification of methods for
Voting terminates on:
measuring surface topography
Spécification géométrique des produits (GPS) — État de surface :
Surfacique —
Partie 6: Classification des méthodes de mesurage de la
topographie de surface
ICS: 17.040.20; 17.040.40; 01.040.17
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 2026
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
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NOTIFICATION OF ANY RELEVANT PATENT
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Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 25178-6:2026(en)
ii
ISO/DIS 25178-6:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General .1
3.2 Classification of methods for measuring areal surface topography and surface texture .2
3.3 Specific methods .3
3.3.1 Areal topography methods .3
3.3.2 Volumetric methods .5
3.3.3 Area integrating methods .5
4 Required elements for profile trace and areal topography methods applied to surface
texture measurement . 6
5 Classification scheme . 6
Annex A (informative) Concise listing of surface topography measurement methods and area
integrating methods . 9
Annex B (informative) Relation to the GPS matrix model .11
Bibliography .12

iii
ISO/DIS 25178-6:2026(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 second edition cancels and replaces the first edition (ISO 25178-6:2010), which has been technically
revised.
The main changes are as follows:
— the separate class of line profiling methods has been eliminated; methods formerly classified as line
profiling are now included in the class of areal topography methods;
— a recently developed method, known as X-ray computed tomography, is introduced into a new class,
known as volumetric methods;
— the method of isometric stereo has been added to the class of areal topography methods, and the special
method of circular profiling no longer appears;
— the definitions of the terms “surface texture” and “surface topography” have been added;
— a schematic diagram of elements required for a functional surface texture measurement system has
been added;
— the informative Annex A “Metrological limitations” has been removed, and an informative Annex A
“Concise listing of surface topography measurement methods and areal averaging methods” has been
added.
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
ISO/DIS 25178-6:2026(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 of the chain 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 information on the relation of this document to other standards and the GPS matrix
model, see Annex B.
This document describes a classification system for methods used primarily for the measurement of surface
topography and surface texture. The classification system provides a context for the development of other
parts of the ISO 25178 series that describe characteristics and measurement standards for some of the
individual methods. Such a classification is also intended to aid in choosing and understanding various
types of methods and in determining which standards apply to their application. The classification system
is aimed to be as general as possible. However, instruments can exist that do not clearly fit within any single
method class.
Since publication of the original version of the standard in 2010, the method of photometric stereo was
developed and X-ray computed tomography was adapted to measuring surface topography. These methods
are added to the listing of methods in this document. In addition, this document specifies the elements
required for a functional surface texture measurement system.
As shown in Annex B, this document is concerned with profile and areal surface texture. However,
measurement of surface texture is often achieved by methods capable of measuring overall surface
topography. Therefore, the terms “surface texture” and “surface topography” are both defined and used in
this document.
v
DRAFT International Standard ISO/DIS 25178-6:2026(en)
Geometrical product specifications (GPS) — Surface texture:
Areal —
Part 6:
Classification of methods for measuring surface topography
1 Scope
This document specifies a classification system for methods used primarily for the measurement of surface
topography and surface texture. It defines three classes of methods, namely, areal-topography methods,
volumetric methods and area integrating methods, illustrates the relationships between the classes,
and briefly describes specific methods. In addition, this document specifies the elements required for a
functional surface texture measurement system.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC Guide 99, ISO 21920-2,
ISO 25178-2, 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 General
3.1.1
measurement coordinate system
system of coordinates in which surface topography is measured
Note 1 to entry: If the reference surface (ISO 25178-2:2021, 3.1.10) is a plane (or portion of a plane), it is common
practice to use a rectangular coordinate system in which the axes form a right-handed Cartesian set, the x-axis being
the direction of tracing lying on the reference surface, the y-axis also lying on the reference surface, and the z-axis being
in an outward direction (from the material to the surrounding medium).
Note 2 to entry: See also the specification coordinate system (ISO 25178-2:2021, 3.1.4).
3.1.2
profile trace
intersection of the surface by an intersection plane perpendicular to the surface and in a specified direction
Note 1 to entry: Formerly termed profile in ISO 25178-2:2012.
[SOURCE: ISO 21920-2:2021, 3.1.4, modified − Notes 1 and 2 to entry have been deleted and replaced by
Note 1 to entry.]
ISO/DIS 25178-6:2026(en)
3.1.3
height
z(x,y)
height of the surface with respect to a reference surface at position x,y
3.1.4
surface texture
geometrical irregularities contained in a scale-limited surface (ISO 25178-2:2021, 3.1.9)
Note 1 to entry: Surface texture is conventionally understood not to include those geometrical structures contributing
to the form and form deviations of the surface.
[SOURCE: ISO 25178-2:2021, 3.1.2]
3.1.5
surface topography
overall three dimensional structure of a surface
Note 1 to entry: See reference [17] for more information.
Note 2 to entry: Surface topography can be expressed as a set of x,y,z coordinate values, or as height (3.1.3) values
z(x,y).
Note 3 to entry: Surface topography includes form, form deviations, surface texture, and surface imperfections.
Note 4 to entry: For a multi-layer surface structure, comprised for example of film layers, surface topography by
default refers to the topmost surface.
3.2 Classification of methods for measuring areal surface topography and surface
texture
3.2.1
areal topography method
surface topography measurement method that produces surface topography data of a surface
Note 1 to entry: The resulting topography images can also be analysed to yield individual profile traces z(x).
Note 2 to entry: Typical acquisition systems can use single point probes scanned mechanically over a surface being
measured or can use electrically scanned, areal imaging arrays integrated into optical microscopes. Other acquisition
methods are also possible.
[18]
Note 3 to entry: Examples of areal topography methods include contact stylus scanning, the optical differential
[19][20] [21][22] [23][24] [25][26]
profiler, confocal chromatic profiling, angle resolved SEM, SEM stereoscopy, scanning
[27] [28][29] [30][31]
tunnelling microscopy, atomic force microscopy, point autofocus profiling, phase shifting
[32] [33][34] [35] [36]
interferometry, coherence scanning interferometry, confocal microscopy, structured light projection
[37][38] [39] [40] [41]
(including triangulation), focus variation, digital holography, and photometric stereo .
3.2.2
volumetric method
surface topography measurement method capable of providing topography data of inner structures as well
as outer surfaces of a workpiece
[42]
Note 1 to entry: An example of a volumetric topography method is X-ray computed tomography .
Note 2 to entry: In contrast to most other methods, a volumetric method yields a “cloud” of x,y,z points.
3.2.3
area integrating method
surface texture measurement method that measures a representative area of a surface and produces
numerical results that depend on area integrated properties of the surface texture
Note 1 to entry: These methods do not produce profile trace data z(x) or areal topography data z(x,y).

ISO/DIS 25178-6:2026(en)
Note 2 to entry: Examples of instruments that have been developed as area integrating methods include those that
[43] [44]
use the techniques of total integrated light scatter, angle-resolved light scatter, parallel plate capacitance
[45][46] [47]
method, and the pneumatic measuring method .
3.3 Specific methods
3.3.1 Areal topography methods
3.3.1.1
contact stylus scanning
surface topography measurement method whereby the probing system uses a contacting stylus whose
motion is converted into a signal z as a function of its (x,y) position
Note 1 to entry: See ISO 25178-601 for more information. See also reference [18].
3.3.1.2
optical differential profiling
surface topography measurement method whereby height differences between two closely spaced points on
a surface are measured in close succession along the direction of traverse and a surface profile is obtained
by integration of these local height differences
Note 1 to entry: Optical differential profiling is also known as Nomarski differential profiling.
Note 2 to entry: See also references [19], [20] for more information.
3.3.1.3
confocal chromatic profiling
surface topography measurement method consisting of a confocal microscope with chromatic objective
integrated with a detection device (e.g. spectrometer) whereby the surface height at a single point is sensed
by the wavelength of light reflected from the surface
Note 1 to entry: See ISO 25178-602 for more information. See also reference [21].
Note 2 to entry: A variation of confocal chromatic profiling, known as chromatic-confocal spectral interferometry
[22]
(CCSI), adds an interferometric component to the setup to overcome limitations in both range and resolution of
either method alone.
3.3.1.4
point autofocus profiling
PAP
surface topography measurement method whereby the local surface height is measured by automatically
centering a focused light beam reflected from the sample on a position sensitive detector as a function of
surface height
Note 1 to entry: See ISO 25178–605 for more information. See also references [30], [31].
3.3.1.5
angle resolved scanning electron microscopy
angle resolved SEM
four quadrant SEM
surface topography measurement method whereby local gradients of a surface are determined by angular
distributions of reflection or secondary electron emission intensity and an areal topography image is
obtained by integration of these local gradients
Note 1 to entry: See references [23], [24] for more information.

ISO/DIS 25178-6:2026(en)
3.3.1.6
SEM stereoscopy
surface topography measurement method whereby two (or sometimes more) scanning electron microscopy
(SEM) images are taken of a surface oriented at slightly different angles and the comparison of the two
images yields a stereo effect, which allows the determination of surface topography
Note 1 to entry: See references [25], [26] for more information.
3.3.1.7
scanning tunnelling microscopy
STM
surface topography measurement method whereby the determination of surface height arises from the
he
...