What this PDS4 inspector checks
The page parses the product root and Identification_Area, inventories namespace and schema-location declarations, and audits logical identity, version, title, information-model version, and product-class agreement. It never follows schema URLs or product references.
File and data-object evidence
Each File_Area is linked to its declared File and direct data objects. Optional selected files provide exact path, case, size, and MD5 evidence. Header, array, table, stream, encoded, inventory, and manifest objects expose byte offsets; fixed-record tables and arrays with supported primitive types receive calculated lengths and physical-bound checks. Resolved ranges are checked for overlap within each file.
Identifiers and references
Duplicate local identifiers and dangling local_identifier_reference values are errors. LID and LIDVID references are inventoried with their reference types, but remain archive-scope references because this single-label preflight does not query the PDS registry or infer bundle membership.
Validation boundary
This is not the canonical PDS4 validator. It does not apply the complete XSD, Schematron, discipline dictionaries, content-validation rules, collection inventories, bundle referential integrity, naming policy, or scientific semantics. It supports common physical layout arithmetic but does not decode data values. Run NASA’s current Validate tool against the complete staged product or archive before delivery.
Frequently asked questions
Why select the referenced files?
The XML label can declare names, sizes, checksums, offsets, and shapes, but only local file selection lets the browser compare those declarations with physical bytes. Selection remains local.
Does a matching MD5 prove authenticity?
No. It proves only that selected bytes match the checksum written in this label. Trust in the label and archive provenance is a separate question.
Why are some object lengths unresolved?
Some PDS4 classes use variable records, encoded data, discipline-specific structures, or data types whose byte size is not safely inferable from the core label alone. The inspector leaves those ranges unresolved instead of guessing.
Authoritative references
Use the current PDS4 Standards Reference, PDS4 Data Dictionary, and NASA’s Validate tool documentation for authoritative product preparation and validation.
Inspect a PDS3 detached label · Inspect a NetCDF classic header · Browse scientific-data tools