TrialPit

What is a TrialPit?

A relatively shallow excavation into the earth's surface, dug either manually or by a mechanical excavator. Samples,observations and tests in the trial pit are referenced in a linear referencing system only (1D). This is a legacy sampling feature to support AGS trial pit constructs.

Realizations

Data model	Concept name	Definition
OGC GeoSciML	TrialPit (candidate)	Same as DIGGS.
IFC	Borehole
AGS	LOCA	AGS LOCA includes exploratory holes of any type, e.g. borehole, trial pit, CPT
DIGGS	TrialPit	A relatively shallow excavation into the earth's surface, dug either manually or by a mechanical excavator. Samples, observations and tests in the trial pit are referenced in a linear referencing system only (1D). This is a legacy sampling feature to support AGS trial pit constructs. The TrenchWall sampling feature should be used to represent more detail on walls of pits or trenches in 2D.

Properties

A proposed list of trial pit properties

Name	Definition
id	Identifier
name	A human-readable display name for the trial pit.
description	A human-readable description for the trial pit.
metadata	A URI referring to a metadata record describing the provenance of data.
remarks	Any general remarks about the trial pit
pitPurpose	The purpose for which the trial pit was created.
pitUse	The curent use of the trial pit which could differ from the purpose for which the trial pit was initially created.
status	The current status of the trial pit (eg. planned, completed, destroyed.
source	Details and citations to source materials for the trial pit and, if available, providing URLs to reference material and publications describing the trial pit. This could be a short text synopsis of key information that would also be in the metadata record referenced by metadata_uri.
associatedFile	Identifies external files associated with this trial pit. This allows for the feature to be further elaborated with information that cannot be represented by ASCII text, such as a photograph or other media, binary data, or a formatted report.
whenDestroyed	The time period during which the trial pit was destroyed or forever abandoned. This date must occur after all related observations, measurements or activities had been performed in the trial pit, and should reflect the time after which no observations or activities are possible..
constructionMethod	The method(s) used for this trial pit (manual, mechanical)
constructionEquipment	The equipment used to construct the trial pit
operator	The organisation or agency responsible for commissioning of the trial pit (as opposed to the agency which drilled the trial pit).
excavator	The organisation responsible for diggingh the trial pit (as opposed to commissioning the trial pit).
pitStartDate	The datetime of the start of excavation formatted according to ISO8601 (e.g., 2012-03-17T00:00:00).
pitEndDate	The date of the end of excavation formatted according to ISO8601 (e.g., 2012-03-28T00:00:00).
pitDepthPlanned	The planned depth of a trial pit e.g. in a site investigation program.
pitDepthConstructed	The total depth of a trial pit as constructed and logged.
pitLength	The length of the long horizontal dimension of the pit.
pitWidth	The length of the short horizontal dimension of the pit.
startPoint	The position relative to the ground surface that marks the origin for meauring distance along a trial pit's trajectory
pitShoring	Description of shoring equipment and method.
pitBackfill	Information on construction of the trial pit backfill.
locationGeometry	2D or 3D point geometry that represents the location of the trial pit at the ground surface in geographic space.
srsName	The URI of a spatial reference system. If collarGeometry is a 2D point, this is the horizontal SRS. If collarGeometry is a 3D point, this must be a either a 3D SRS, a known compound SRS, or the EPSG code of the horizontal component of a compound SRS.
elevation_srsName	The URI of a spatial reference system of the elevation of the collarGeometry. (e.g., mean sea level). Mandatory if collarGeometry and srsName is the EPSG code of the horizontal component of a compound SRS. elevation_srsName shall be a one dimensional vertical SRS (i.e., EPSG code in the range 5600-5799).
positionalAccuracy	An estimate of the accuracy of the location of the collarGeometry. Ideally, this would be a quantitative estimate of accuracy (e.g., 20 metres).
locality	Non-coordinate location information for a trial pit.
localCoordinates	A geometry object that holds the values of local coordinates for the trial pit location. This object is used to carry information about the location of a feature in its original local reference system if not originally recorded in a well-known SRS
trajectoryGeometry	A geometry lineString in 3D space that represents the top and base of the trial pit. This object is of the same SRS as locationGeometry.
linearReferencing	Defines the linear spatial reference system for the trial pit. This LSRS can then be used to define the locations of observations within the trial pit as a 1D position along the trial pit's trajectory, rather than in geographic coordinates.

FAQ

How are observed properties that vary laterally in a trial pit handled in 1D?

Observations of the same property where results vary laterally in the pit at the same depth are assigned different stratum codes. A stratum code is a letter or number code that links the stratum shown on a face sketch of the trial pit to the observation. In OMS, this would be accomplished by having different features of interest identified for the same 1D location.

Github issue:

https://github.com/opengeospatial/Geotech/issues/18