SEG-Y Coordinate Security

What it is for

Seismic data has to be shared — with a processing vendor, a farm-in partner, a data room — and the coordinates in it are frequently the most sensitive thing it carries. Where a survey was shot can reveal an exploration position long before anyone wants that known. But stripping the coordinates outright breaks the data: line geometry, relative positions and bin topology all have to survive, or what you shipped is no longer usable seismic.

This tool removes direct georeferencing while preserving the geometry, applying one consistent local-grid transformation across a whole delivery set — then independently verifies the result before you hand it over.

Three steps, in this order

Audit reads every trace by default and examines all three standard coordinate pairs, the scalars, the units, and both the primary and extended textual headers. A quick mode exists for exploration but deliberately cannot be used to build a plan — a sanitization decision should not rest on a sample.

Plan produces one reviewable transformation for the whole dataset: rotation, scale, reflection and target origin. Every populated field, whether selected or excluded, is checked against the scalar before the plan is written, so a magnitude that cannot be re-encoded is rejected up front rather than surfacing as an overflow mid-sanitize. Excluding a field the audit flagged as genuinely georeferenced requires you to acknowledge that explicitly.

Sanitize writes copies. Inputs are never modified and existing outputs are never overwritten. The whole set is written to a staging directory, every file is reopened and checked, and the result is promoted atomically only once all of them succeed — so an interrupted run cannot leave a half-sanitized delivery that looks finished.

Verify then checks the output independently, and can also be pointed at a delivery someone else produced, on its own terms.

What is preserved, and what is replaced

Direct map coordinates in the standard CDP, source and receiver header locations are replaced. Binary headers, seismic samples, trace order, inline and crossline words and bin topology are left unchanged, so the output still loads as seismic. Textual headers are replaced with a controlled functional header that declares the preserved inline/crossline bytes, the transformed X/Y bytes, the scalar, the units and the sample layout — and states plainly that the local grid has no external reference.

Vendor-specific or duplicated coordinates in nonstandard header bytes are not rewritten automatically. They are reported for review, and a reviewed mapping can be declared in the plan so it is transformed along with the standard fields, restricted to a fixed set of safe offsets.

The honest security boundary

This is the part worth reading before relying on the tool. Preserved geometry remains a recognisable fingerprint. If someone already holds another copy of the same survey, the shape of the acquisition can be matched against it. The tool therefore reports no direct georeferencing detected — never that re-identification is impossible, because that would be a claim it cannot support.

The audit, the plan and the internal manifest disclose source paths, coordinate evidence and the transformation itself. They are working files and must stay out of the external delivery.

The desktop application

Audit, Transformation Plan, Sanitize, Verify, Verify Existing, Geometry QA, 3D Survey QA and Settings screens, with Verify Existing sitting outside the pipeline so a third-party file can be checked independently. Geometry QA displays one line or every verified line and fits the map to the loaded geometry. A bundled, fully offline Azerbaijan and Caspian Sea basemap outline is available as a background that needs no network at all, and public map tiles stay disabled until explicitly allowed — you should not have to send survey geometry to a tile server to look at it. A saved plan can be reloaded to reuse its rotation, scale and scalar when adding more lines or a 3D volume to an existing batch.

What it does not do