INDUSTRY FIELD GUIDE
Land survey control points and datum metadata for AI
Two coordinate tables can share point names while using different datums, units or epochs.
NAICS 541370 · Surveying and Mapping (except Geophysical) Services
Two coordinate tables can share point names while using different datums, units or epochs. NOAA’s National Geodetic Survey explains datum concepts. A survey practice can make a fictional comparison that tests metadata handling and prevents unsupported merges. NOAA National Geodetic Survey datums
Create two abstract control tables with similarly named points. Give one a declared coordinate basis and leave it ambiguous on the other. Ask which pair can be compared and what information is needed for the remainder. Include an independent reviewer key for identity, datum, units and coordinate precision.
Use fictitious geometry and labels. Leave boundary claims, client maps, real coordinates and critical infrastructure out. Preserve the stated source and metadata in every exported exercise.
Describe a synthetic survey control sample
Original Fiund exercise
A shared point name does not establish a shared coordinate basis
Abstract invented control tables use no real coordinates or boundary information. The exercise checks identity and metadata rather than performing a survey transformation.
| Record | Source | What it records |
|---|---|---|
| LSC1 | Practice table A | Point P1 coordinates 10,20; basis D-A, units U, epoch E1, stated precision one unit. |
| LSC2 | Practice table B | P1 coordinates 11,21; datum and epoch unspecified, units U. No identity cross-reference beyond the short name. |
| LSC3 | Compatible check table | Point P1 explicitly linked to table A under D-A/U/E1; coordinates 10,20 at the same stated precision. |
Question for the model
Which records support a same-basis comparison, and can A-to-B differences be interpreted as movement from the shared name and units?
Show the reference answer and checks
LSC1 and LSC3 explicitly share point identity, D-A basis, U units, E1 epoch and stated precision, supporting their documented same-basis comparison. LSC2 omits datum, epoch and a verified point link. Its one-unit coordinate differences do not establish physical movement or a valid transformation. Preserve all coordinate metadata and request the missing basis before merging or interpreting the tables.
- Joining coordinate tables on short point names alone.
- Calling a coordinate difference movement when datum, epoch or identity is unknown.
Fields to preserve
- Point identity and source link
- Defines whether two rows describe the same control.
- Datum, units and epoch
- Preserves the reference basis.
- Stated precision
- Limits interpretations of small differences.
Test another case
Provide B's datum but a different epoch and no transformation. Require the model to resolve one metadata field without declaring full comparability.
Use fictional geometry and labels. Exclude boundaries, client maps, actual coordinates and infrastructure.
Discuss a contribution
Describe the sources you control, the task they could support and what has already been checked. Use the existing-data assessment for an archive or the collection brief for a new recording project. The contributor agreement defines Fiund’s licensing authority and compensation. A guide or fictional exercise does not establish an accepted collection or a sale.