Imported from VectorSpaceLab/AREX-Skill (skills/repositories/repo-skills/geoparquet/sub-skills/validate-geoparquet/SKILL.md). Install upstream with npx skills add VectorSpaceLab/AREX-Skill --skill validate-geoparquet. Copyright stays with the author (Apache 2.0).

Validate GeoParquet

Use this skill when a user asks whether a Parquet file is GeoParquet, wants to check the geo metadata, needs to inspect a native geometry logical type or geospatial statistics, or is troubleshooting WKB, CRS, geometry_types, bbox, edges, orientation, or epoch. It covers vector GeoParquet 2.0. It is not a general-purpose writer, converter, package installer, benchmark runner, or raster validator. For publication layout and external writer selection, route to ../distribute-geoparquet/SKILL.md. For the alpha raster proposal, route to ../parquet-raster/SKILL.md.

The bundled helpers are deliberately checkout-independent and offline by default. They require only the relevant installed Python dependencies (normally PyArrow and jsonschema; native fixture creation additionally uses geoarrow-pyarrow). The verified CPU smoke baseline is pyarrow 25.0.1, geoarrow-pyarrow 0.2.0, geopandas 1.1.4, and jsonschema 4.26.0, with referencing imports succeeding. Its local example reports geo.version 2.0.0, native Geometry, and geo statistics. Probe the actual runtime before relying on these versions. The repository described by the source evidence is a specification and example suite, not an installable Python package; do not claim that installing this skill installs a GeoParquet writer.

Conformance target

A GeoParquet 2.0 candidate has two coordinated contracts:

1. Native Parquet geometry. Every geometry column is a root-level, required or optional BYTE_ARRAY annotated as native GEOMETRY or GEOGRAPHY. It is not repeated, nested, a list, a map, or a struct. The values use WKB and x,y axis order regardless of CRS axis declarations.
2. Footer metadata. File key/value metadata has an exact geo key whose UTF-8 value is JSON. The object has version: "2.0.0", a non-empty primary_column, and a non-empty columns object. Every geometry column is listed with encoding: "WKB" and a geometry_types array.

Metadata alone is not enough: a plain binary WKB column carrying plausible geo JSON is non-conformant GeoParquet 2.0. Conversely, native Parquet geometry without the geo metadata block is useful native geospatial Parquet but is not a self-described GeoParquet 2.0 file.

Read the detailed rules in references/vector-spec.md and the schema and offline-validation boundary in references/metadata-schema.md.

Operating procedure

1. Establish the claim

Record the intended version, each geometry column, whether this is a single file or a partition, and whether GeoParquet 1.1 readers are required. Do not infer format support from a filename, a successful generic Parquet open, or a writer name. Preserve the exact tool and library versions used to create the file.

2. Inspect the footer before interpreting metadata

Run the bundled inspector from any working directory:

python /path/to/inspect_geoparquet.py data.parquet

For a strict gate, use --require-conformant --require-statistics. Review the geo key, schema paths, physical types, definition/repetition levels, native logical type JSON, row-group count, and every row-group's geospatial statistics. The expected geometry leaf is root-level BYTE_ARRAY, max repetition level 0, and native Geometry or Geography.

3. Validate the geo object locally

A metadata file may be the bare object or {"geo": {...}}:

python /path/to/validate_geo_metadata.py metadata.json

To validate a metadata file against a Parquet footer, use:

python /path/to/validate_geo_metadata.py metadata.json --parquet data.parquet

Passing data.parquet as the input extracts the footer geo value directly. The default is local and does not fetch the PROJJSON schema. A non-zero exit means the metadata or requested footer checks failed. Use --allow-missing-statistics only when the report explicitly records that the statistics gate was deferred; it does not turn absent statistics into verified statistics. A supplied --schema is also localized offline if it contains a remote $ref.

4. Reconcile metadata, logical types, and statistics

For every metadata geometry column, check that:

• the column exists as a root-level Parquet field and is WKB BYTE_ARRAY;
• it is required or optional, never repeated or nested;
• its native logical type is Geometry or Geography;
• the primary_column names both a metadata entry and a native geometry field;
• the geometry type list is complete, unique, and dimension-suffixed correctly;
• known types match native geospatial_types statistics, while [] means unknown rather than “Point”;
• the file-level bbox is in the same CRS and contains every row-group extent;
• native statistics are present for the strict 2.0 inspection gate; and
• native CRS semantics agree with geo.columns[*].crs, even when the two representations are not byte-for-byte identical.

The local helper reports metadata-level CRS shape and footer facts, but it does not resolve an authority registry or prove semantic CRS equivalence. Record those as unresolved unless a separately approved CRS-aware check is available.

5. Apply the exact field rules

• encoding is exactly WKB.
• Allowed base geometry types are Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, and GeometryCollection. Dimension suffixes are exactly Z, M, or ZM; Point Z is valid but PointZ is not. Types must be unique and complete.
• crs in GeoParquet metadata is inline PROJJSON or null, never an authority string. If absent, the default is OGC:CRS84 (longitude, latitude on WGS84); null means undefined or unknown. On the native logical type, CRS may be inline PROJJSON, <authority>:<code> such as EPSG:4326, srid:<id> (srid:0 means undefined/unknown), or projjson:<key_name>.
• edges is one of planar, spherical, vincenty, thomas, andoyer, or karney; absent means planar. orientation, when present, is only counterclockwise and asserts counterclockwise exterior and clockwise interior polygon rings.
• bbox is 4 values for XY, 6 for XYZ, or 8 for XYZM, with minimums followed by maximums (and RFC 7946 geographic ordering). A 5-element bbox is invalid; M-only bounds cannot be expressed in this metadata field. epoch is an optional decimal year for a dynamic CRS and is per column.
• The native logical type's geospatial statistics should expose geometry type codes and x/y extents, with z/m extents when applicable. A supplied metadata bbox must contain all row-group extents.

For a compact field reference, see references/vector-spec.md. For schema-valid and invalid examples, see references/metadata-schema.md.

6. Classify and recover

Classify the result as conformant candidate only when local metadata, native schema, WKB/physical layout, and required statistics checks pass. Use non-conformant for any required failure, especially metadata with no native logical type, PointZ, duplicate geometry types, a five-element bbox, a string metadata CRS, nested/repeated geometry, or mismatched statistics. Use not verified when a full PROJJSON validation, CRS equivalence check, or required statistics observation could not run. Do not relabel “not verified” as pass.

Follow references/inspection-workflow.md for the complete decision sequence and references/troubleshooting.md for bounded recovery actions. Keep raw reports and review artifacts outside this runtime skill tree.

Safe bundled helpers

All runtime files are linked here so they can be discovered without source checkout assumptions:

• scripts/validate_geo_metadata.py — offline metadata validator; accepts bare/wrapped JSON or a Parquet footer and returns non-zero for invalid metadata or failed requested footer checks.
• scripts/inspect_geoparquet.py — emits a JSON footer report with geo metadata, schema/logical-type facts, native columns, and row-group statistics; non-conformant reports return non-zero.
• scripts/write_minimal_geo_metadata.py — writes an explicit one-row native fixture when geoarrow-pyarrow is available, or a deliberate --plain non-native fixture for boundary tests.
• scripts/make_wkb_fixture.py — writes a deterministic WKB fixture for each supported base geometry and XY/XYZ/XYM/XYZM.

Each script supports --help, explicit paths, arbitrary current working directories, and no network access. The fixture scripts refuse to overwrite an existing output unless --force is supplied.

GeoParquet 1.1 compatibility boundary

GeoParquet 1.1 commonly stores WKB BYTE_ARRAY values with legacy geo metadata and a bbox covering. That is a deliberate compatibility target for older or heterogeneous readers, not a 2.0 label: it lacks the required native GEOMETRY/GEOGRAPHY logical type. The compatibility guidance assumes a geometry or geography column, WGS84 longitude/latitude (OGC:CRS84), and planar or spherical edges respectively. Prefer a real 1.1 writer when that reader matrix is mandatory, and validate the 1.1 artifact as 1.1 rather than calling it 2.0. A native-type-only file without geo metadata is likewise not full 2.0 GeoParquet.

Routing links

• Publication, compression, ordering, partitioning, STAC, and external writer selection: ../distribute-geoparquet/SKILL.md.
• Alpha raster proposal: ../parquet-raster/SKILL.md.
• Normative vector rules: references/vector-spec.md.
• Metadata schema and offline caveats: references/metadata-schema.md.
• Footer workflow: references/inspection-workflow.md.
• Troubleshooting: references/troubleshooting.md.