MAG errors worth detecting before closing an environmental delivery

The most expensive MAG errors are not always invalid geometries. They also occur when a team uses an outdated package, treats a class required for its scope as optional, changes a domain to accommodate data, loses the CRS during export or delivers layers without a clear connection to the study. Early detection requires comparison of structure, content and traceability, not merely opening the geodatabase.

Fix the source of truth before transformation

The reference framework is Resolution 2182 of 2016 and the current MAG package for the procedure’s scope. Consult ANLA’s official instruments, permits and procedures section before applying rules: a locally stored template may have become outdated.

Classify findings by cause. Structural findings compare the artefact with the package; semantic findings review meaning, units and domains; spatial findings cover geometry and relationships; documentary findings check source, date and lineage. Combining them in one list makes ownership unclear and may lead to corrections that damage valid information.

Before correcting anything, classify each finding as structural, semantic, spatial or documentary and assign an owner. A routine can flag an unknown domain but should not replace it automatically; it may also detect problematic geometry without deciding whether the object was conditional. Retain the previous value, applied rule and rationale for every change. Test corrections on a representative sample and reopen relationships, domains and attachments in the exported package. Closure requires evidence for each finding, not merely reducing the total counter to zero.

Recommended sequence

1. Verify. Confirm that the template matches the official version and the procedure’s specific scope.
2. Map. Compare classes, fields, types, lengths, domains and nulls without changing the source.
3. Prepare. Review CRS, empty geometry, duplicates, self-intersections and expected inter-layer relationships.
4. Check. Trace every value to its study, appendix, date, method and production owner.
5. Close. Record correction, accepted exception and evidence before producing the final package.

Minimum control evidence

The technical preparation record should retain:

• no silent renaming merely to match fields.
• documented units and domains.
• spatial rules suited to each layer type.
• final review of the artefact that will actually be delivered.

What the diagnostic cannot promise

Not every difference is an error, and not every error can be corrected automatically. A layer may be conditional, a null may be justified and a complex geometry may be valid. Decisions require the instrument, scope and knowledge of the study. GeoSAT’s precheck is an unofficial aid: it must not promise approval or present its report as ANLA communication. The authority and its official channels retain the decision.

Review the specialised GeoSAT service to define scope and the related cluster to identify interoperability, environmental or territorial dependencies. This guide is informational; service pages explain evidence, tooling and an appropriate next step without promising an official decision.