A site investigation is never entirely predictable.
A field technician may find exactly what was expected at one location and encounter an unusual layer, unexpected material or an obstruction just a few metres further on. In situations like these, the technician’s additional observations matter, for example when a borehole has to be relocated or cannot be continued.
This is also what makes standardisation in site investigation a sensitive subject. If too much is reduced to predefined choices, an unusual situation may not be recorded properly. But complete freedom creates a different problem: differences in how information is recorded start to look like differences in what was actually observed.
The same observation, three different values
Take three field technicians looking at the same water. All three consider it clear.
One records ‘clear’,
another ‘transparent’
and the third ‘turbidity 0’.
There is no difference in the observation. There is a difference in the data.
When a project manager compares observations from different technicians or projects, those three values need to mean the same thing. Otherwise, a difference in wording can be mistaken for a difference in what was observed.
This becomes particularly important during follow-up investigations or monitoring programmes. You need to be able to determine whether conditions have genuinely changed over time. The same applies when comparing different boreholes or soil layers, for example to track where contamination is being encountered. If the same situation is described differently each time, that comparison becomes unnecessarily difficult.
A common way of recording recurring observations helps ensure that differences in the data actually represent differences in the field, rather than the vocabulary chosen by the person entering the data.
Not everything fits into a predefined list
That does not mean every possible answer needs to be included in a predefined list.
There is a fundamental difference between information that needs to be unambiguous and information that provides context about an unusual situation.
A status or common observation can often be recorded using agreed values. A relocated borehole is different. The fact that it was relocated is easy to record in a structured way. The reason for the relocation may be important to someone reviewing the investigation later.
The same applies to unexpected material or an unusual inclusion. If it does not fit one of the available categories, the technician needs to be able to record what was actually found. Choosing the closest available option may produce tidy data, but not necessarily better information.
That is where the limit of standardisation lies: reducing unnecessary variation in how the same information is recorded without removing the differences that genuinely matter.
International standards already combine common frameworks with site-specific judgement
This balance is also visible in international standards for soil investigation.
ISO 25177 provides guidance for describing soil and its environmental context in the field, including observations at site, layer and horizon level. It also recognises that not every possible item needs to be recorded for every investigation.
The ISO 18400 series takes a similar approach to soil sampling. ISO 18400-101 provides a framework for developing sampling plans on a case-by-case basis, while ISO 18400-203 specifically addresses the investigation of potentially contaminated sites. The common framework therefore does not remove the need to adapt an investigation to its purpose and the conditions at the site.
The same principle applies to field data: common rules can provide consistency without prescribing every professional judgement made on site.
Digital data makes recording differences more visible
On paper, an experienced colleague can often use the surrounding context to understand that ‘clear’ and ‘transparent’ describe the same observation.
Digital data is less forgiving. Without an agreed definition or mapping, they are two separate values. This becomes visible when data is filtered, combined across projects, used in GIS or exchanged between systems.
The way an observation is recorded in the field therefore affects what can be done with that information later.
At TerraIndex, this is a recurring consideration when developing digital field registration. Which information needs a consistent meaning because it will later be compared or reused? And where does a technician need room to add context because the situation could not have been predicted in advance?
More dropdown lists are therefore not automatically the answer. What matters more is which information needs to remain unambiguous for later use and where context needs to be preserved. At TerraIndex, we regularly discuss these decisions with field technicians and project managers. Their practical experience informs how we design field registration.
To learn more about what digitalisation means for the entire soil investigation process, read our article on digitalising soil investigation.
A difference should mean something
If two records are different, you want that difference to tell you something about what was actually observed, rather than simply reflecting two different ways of describing the same thing.
At the same time, an unusual situation needs to remain visible as an unusual situation. If a standard forces an observation into the closest available category, useful information can disappear.
Good standardisation therefore reduces differences created by registration itself, without removing the differences found during the investigation.
What does digital field registration look like in practice?
See how Antea Group digitised its soil investigation process and works with structured data that is available in the office as soon as it is captured in the field.