DIGGS Instances

What is a DIGGS Instance?

A DIGGS instance is a structured XML document that follows the DIGGS schema. The instance is what stores the geotechnical data (as ASCII text) and typically is a computer file (with a .diggs or .xml extension). However, DIGGS instances can also be stored in database fields and data transfer using a DIGGS instance can be accomplished on the fly entirely in software, without producing a file.

What Goes Into a DIGGS Instance?

As with all XML instances, a DIGGS instance must have, as the first line, an XML declaration <?xml version="1.0" ?> followed by a root element - in this case <Diggs> - with attributes that hold necessary namespaces and schema references to ensure compliance with the DIGGS format​. To ensure that any instance document has proper namespace declarations and schema reference, the start tag should look like this (version 3):

<Diggs xmlns="http://diggsml.org/schemas/3" xmlns:diggs="http://diggsml.org/schemas/3"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:gml="http://www.opengis.net/gml/3.2" xmlns:glr="http://www.opengis.net/gml/3.3/lr"
xsi:schemaLocation="http://diggsml.org/schemas/3 https://diggsml.org/schemas/3.0.0/Diggs.xsd"
gml:id="YourID">

where the value of the gml:id attribute should be unique within the instance and must be an NCName (Non-Colonized Name), meaning it must start with a letter or underscore and contain only letters, digits, hyphens, underscores, and periods.

Within the root element are nested top-level elements (DIGGS properties) that each represent different aspects of a geotechnical project; for DIGGS we refer to these top level properties as object classes. They are, in sequence order:

1. documentInformation (Required) – Defines metadata like creation date, author, and version tracking​ for this specific DIGGS instance.

2. project – Represents a business activity that encompasses an investigation or construction where observations are made and/or data are collected. Projects may include ground investigations, project designs and specifications, construction activities, or simply a collection of data that may be part of a research project.

3. program – Organizes multiple projects under a broader initiative.

4. samplingFeature – Represents locations or objects from which geotechnical data are collected (e.g., boreholes, CPT soundings).

5. samplingActivity – Records actions taken to obtain samples, such as drilling or coring.

6. sample – Captures data on collected physical samples of soil, rock, or fluid.

7. observation – Stores subjective or categorical geotechnical observations (e.g., color, soil classification).

8. measurement – Contains numerical test results or monitoring data (e.g., SPT, CPT, Atterberg Limits).

9. constructionActivity – Logs construction-related activities like foundation installation or grouting.

10. group – Allows grouping of related objects for easier data organization​.

A DIGGS XML file follows a defined structure and must include a root element with necessary namespaces and schema references to ensure compliance with the DIGGS format​.