Site Datum
Definition
A fixed reference point, established by total station or RTK-GPS, to which all survey grid positions are tied. Ensures that anomaly positions are reproducible and can be handed to excavators as actionable coordinates.
- Establishment method
- Total station or RTK-GPS survey
- Role
- Fixed reference point for the site grid
- Purpose
- Reproducible anomaly and feature positions
- Downstream use
- Handed to excavators as actionable coordinates
Common questions
What happens to the geophysical survey data if the site datum is lost or moved?+
Every position recorded relative to that datum becomes unreliable, since the grid has no fixed anchor to tie back to; investigators would need to re-establish and re-survey the site, which can be impossible once the original ground surface has been disturbed.
Why use RTK-GPS or a total station rather than a handheld GPS unit for the datum?+
A handheld consumer GPS has metre-level accuracy, which is not precise enough to reliably relocate a small anomaly for excavation, while RTK-GPS and total stations achieve centimetre-level or better precision needed for actionable dig coordinates.
Related terms
- Confidence Ranking
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- Decision Framework
- A structured protocol for selecting geophysical methods based on documented site characteristics (soil type, target depth, cultural noise) before fieldwork begins, with...
- False Positive
- A test result that indicates the presence of a target analyte when it is absent. In forensic serology this may mean incorrectly...
- GIS Co-Registration
- Assigning consistent spatial coordinates to all survey datasets so that anomalies from different instruments can be overlaid and compared at matching ground...
- Ground-Truthing
- The physical investigation (probing, test pitting, or full excavation) of a geophysical anomaly to determine whether it represents a genuine forensic target....