For the data modelling on the GeoTech IE, in addition to the basic OGC geospatial standards, the following two standards where of core interest, strongly guiding the final data model.

ISO19148

Linear Referencing Systems enable the specification of positions along linear objects. The approach is based upon the Generalized Model for Linear Referencing[12] first standardized within ISO 19133:2005. This document extends that which was included in ISO 19133, both in functionality and explanation.

ISO 19109 supports features representing discrete objects with attributes with values which apply to the entire feature. ISO 19123 allows the attribute value to vary, depending upon the location within a feature, but does not support the assignment of attribute values to a single point or length along a linear feature. Linearly located events provide the mechanism for specifying attribution of linear objects when the attribute value varies along the length of a linear feature. A Linear Referencing System is used to specify where along the linear object each attribute value applies. The same mechanism can be used to specify where along a linear object another object is located, such as guardrail or a traffic accident.

It is common practice to segment a linear object with linearly located events, based upon one or more of its attributes. The resultant linear segments are attributed with just the attributes used in the segmentation process, ensuring that the linear segments are homogeneous in value for these segmenting attributes.

ISO19156

The Observations, Measurements, and Samples standard (OMS), jointly prepared and published by the Open Geospatial Consortium and ISO/TC 211 as OGC Abstract Specification Topic 20 (OGC 20-082r4) and ISO 19156:2023, defines a conceptual schema for observations, for features involved in the observation process, and for features involved in sampling when making observations. Models support the exchange of information describing observation acts and their results, both within and between different scientific and technical communities.

Observations commonly involve sampling of an ultimate feature-of-interest. OMS defines a common set of sample types according to their spatial, material (for ex situ observations), or statistical nature. The Standard’s schema includes relationships between sample features (sub-sampling, derived samples). It also adds concepts that were deemed missing in the previous version and provides additional clarification to the provided concepts and their relationships while keeping the core data model mostly intact. In addition, a new fine-grained requirements class structure has been created, enabling implementations to unambiguously declare the parts of the standard they conform to.

The abstract data models described in OMS provide common concepts and logical structures for exchanging observational data and metadata between various information systems as well as for harmonized handling of such information from various heterogeneous sources. Technical implementation standards and profiles, on the other hand, provide concrete solutions tailored for storing, exchanging and processing OMS information in particular technical environments and use cases.

The work on revising existing OMS-related OGC Implementation Standards to fully comply with the OGC 20-082r4 requirements is in progress in OGC, including Sensor Things API and Timeseries Markup Language. Work is also underway for harmonization between the already closely related OMS and the W3C SSN/SOSA Standards. New OGC Implementation Standards are being pursued for OMS JSON encoding and OMS related dataset metadata led by the OGC OMS Standards Working Group.

The OMS family of Standards contribute to the FAIR (Findable, Accessible, Interoperable, Reusable) principles for various kinds of measurable information, including environmental monitoring as well as remote and in-situ sensing by providing a common conceptual framework for discovering, collecting, and analyzing related information from various sources and data providers.

For which geotech concepts do we propose to use ISO19148 and ISO19156?

Those data models and the extensions designed for them are proposed in order to realize all the concepts listed in Book A, including:

• Observation
• Sampling
• Borehole
• MaterialSample

How do we propose to connect ISO19148 and ISO19156?

The connection is detailled in this chapter