AndreaBozzo/ceres-open-data-index

Ceres Open Data Index

A curated index of 2,745,021 open dataset records from 567 portal exports across 40+ countries and international sources, with cross-portal duplicates flagged. The snapshot includes normalized dataset metadata, resource links when supplied by the source, and a reproducible manifest with file checksums.

Dataset description

This dataset was harvested by Ceres, a harvest-first open-data toolkit. It covers ten source families: CKAN, DCAT-AP (udata REST), SPARQL-backed DCAT, Project Open Data (data.json), Socrata, OpenDataSoft, ArcGIS Hub, OGC Records/CSW, collection-level STAC, and SDMX. Noise is filtered during export; likely cross-portal duplicates are flagged but retained.

What's included

• Titles, descriptions, URLs, tags, organizations, licenses, and source provenance
• Resource-level names, formats, media types, URLs, and schema field counts when available
• A heuristic cross-portal duplicate signal (is_duplicate)
• Per-portal Parquet subsets for targeted analysis
• A versioned manifest, quality report, and snapshot-to-snapshot changelog

What's not included

• The data files themselves (CSVs, shapefiles, and similar assets)
• Embedding vectors, which are model-specific
• A canonical entity-resolution result; is_duplicate is only a title-based heuristic

Resource links are present for 1,997,796 rows (72.8%); 96,395 rows (3.5%) include at least one resource schema. Coverage varies substantially by source API.

Dataset structure

Schema

Column	Type	Nullable	Description
original_id	string	no	Record identifier from the source portal
source_portal	string	no	Canonical source portal URL
portal_name	string	no	Stable export name for the portal
url	string	no	Dataset or catalog-record landing page
title	string	no	Record title
description	string	yes	Record description
record_kind	string	no	Normalized kind of catalog record
tags	string	yes	Comma-separated source tags
organization	string	yes	Publishing organization
license	string	yes	License title or identifier
metadata_created	string	yes	Source creation date (ISO 8601)
metadata_modified	string	yes	Source modification date (ISO 8601)
first_seen_at	string	no	When Ceres first indexed the record (RFC 3339)
language	string	yes	Source or portal language label
is_duplicate	boolean	no	Exact case-insensitive title also occurs on another canonical portal
resources	list of structs	no	Resource entries: name, format, media_type, url, and field_count

Files

• all.parquet — complete dataset (2,745,021 rows)
• data/<portal>.parquet — 567 portal subsets; rows repeat those in all.parquet
• identity.parquet — record keys and content hashes used for snapshot diffs
• metadata.json — snapshot manifest, Ceres provenance, curation counts, aliases, and SHA-256 checksums
• reports.json / report.md — coverage and field-completeness report
• changelog.json / changelog.md — added, changed, removed, and unchanged counts versus v5

Manifest paths are unique. This release contains 569 Parquet files in total (all.parquet, identity.parquet, and 567 portal subsets), and every file's size, checksum, and row count was verified before publication.

Largest portal exports

Top 48 by exported row count (of 567 total):

Portal export	Source	Family/profile	Rows
eu-open-data	data.europa.eu	DCAT / SPARQL	712,481
catalog-data-gov	catalog.data.gov	CKAN	399,597
queensland	data.qld.gov.au	CKAN	181,970
www-govdata-de	govdata.de	CKAN	158,177
data-gov-au	data.gov.au	CKAN	139,729
ods-hub	data.opendatasoft.com	OpenDataSoft	91,100
dati-gov-it	dati.gov.it	CKAN	65,077
ckan-publishing-service-gov-uk	ckan.publishing.service.gov.uk	CKAN	57,244
data-gov-uk	data.gov.uk	CKAN	57,060
spain-datos	datos.gob.es	DCAT / SPARQL	49,930
open-canada-ca	open.canada.ca	CKAN	47,437
data-gouv-fr	data.gouv.fr	DCAT / udata	43,186
data-gov-ua	data.gov.ua	CKAN	36,960
banque-de-france	webstat.banque-france.fr	OpenDataSoft	35,837
czech-republic	data.gov.cz	DCAT / SPARQL	32,660
data-humdata-org	data.humdata.org	CKAN	28,039
geodati-gov-it	geodati.gov.it	geospatial catalog	23,578
healthdata-gov	healthdata.gov	Project Open Data	22,417
greece	data.gov.gr	CKAN	21,900
data-gov-ie	data.gov.ie	CKAN	21,267
california-natural-resources	data.cnra.ca.gov	CKAN	21,114
data-overheid-nl	data.overheid.nl	CKAN	20,796
dados-gov-pt	dados.gov.pt	DCAT / udata	20,792
spain-idee-csw	idee.es	OGC Records/CSW	18,690
pndb	pndb.opendatasoft.com	OpenDataSoft	17,710
netl-edx	edx.netl.doe.gov	CKAN	17,186
switzerland	opendata.swiss	CKAN	15,863
www-geocatalogue-fr	geocatalogue.fr	geospatial catalog	14,960
nrw	open.nrw.de	CKAN	14,910
japan	data.e-gov.go.jp	CKAN	12,276
dati-toscana-it	dati.toscana.it	CKAN	12,214
slovakia	data.slovensko.sk	DCAT / SPARQL	11,748
metadane-podgik-pl	metadane.podgik.pl	geospatial catalog	11,264
statistics-lithuania-sdmx	osp-rs.stat.gov.lt	SDMX	9,500
www-geonorge-no	geonorge.no	geospatial catalog	9,190
podatki-gov-si	podatki.gov.si	CKAN	8,956
norway	data.norge.no	DCAT / SPARQL	8,669
catalog-data-metro-tokyo-lg-jp	metro.tokyo.lg.jp	CKAN	8,483
nationaalgeoregister-nl	nationaalgeoregister.nl	geospatial catalog	8,140
www-datos-gov-co	datos.gov.co	Socrata	7,773
emodnet-csw	emodnet.ec.europa.eu	OGC Records/CSW	7,104
www-datosabiertos-gob-pa	datosabiertos.gob.pa	CKAN	5,607
discover-data-vic-gov-au	discover.data.vic.gov.au	CKAN	5,578
dati-regione-marche-it	dati.regione.marche.it	CKAN	5,450
data-gov-ro	data.gov.ro	CKAN	5,018
data-virginia-gov	data.virginia.gov	Project Open Data	4,825
data-ca-gov	data.ca.gov	Project Open Data	4,506
cioos-pacific	catalogue.cioos.ca	CKAN	3,484

The full portal breakdown and exact source URLs are recorded in metadata.json and reports.json. Alias feeds such as a portal's root API and its /data.json endpoint can share a canonical export name without being treated as independent sources.

Coverage and quality

Exporter classification by source type: unmapped/legacy config 1,318,679 · DCAT 835,846 · CKAN 327,737 · OpenDataSoft 177,191 · OGC Records/CSW 27,264 · ArcGIS 24,302 · SDMX 15,160 · Socrata 11,833 · STAC 7,009. The unknown classification reflects missing type annotations in the export configuration, not unknown provenance; source URLs remain present.

DCAT profiles account for 817,318 SPARQL, 12,058 static JSON, and 3,477 udata REST records. Field completeness is: description 100.0% · resources 72.8% · modification date 52.4% · organization 51.2% · tags 45.3% · license 31.8% · resource schema 3.5%.

Language labels are source/portal metadata rather than per-row language detection. The largest labels are English (en) 1,182,023; unknown 1,161,936; eng 87,963; Spanish 76,992; French 75,086; Ukrainian 36,301; Czech 32,879; Greek 21,900; Japanese 14,224; Slovak 11,748; and Norwegian 8,669.

Loading the dataset

import pandas as pd

df = pd.read_parquet("all.parquet")
df_us = pd.read_parquet("data/catalog-data-gov.parquet")
likely_unique = df[~df["is_duplicate"]]

Or with DuckDB:

SELECT source_portal, count(*) AS records
FROM read_parquet('all.parquet')
GROUP BY source_portal
ORDER BY records DESC;

Dataset creation

Harvesting methodology

Ceres harvests each portal through its native API with a streaming, incremental pipeline:

1. CKAN portals use paged package_search requests with adaptive page sizing and retry behavior.
2. DCAT udata catalogs use paged JSON-LD; Project Open Data catalogs consume data.json documents.
3. SPARQL-backed DCAT catalogs use stable keyset pagination, bounded distribution-property queries, and URI-level deduplication.
4. Socrata uses the Discovery API; OpenDataSoft uses the Explore API with a keyset cursor beyond its 10,000-row window.
5. ArcGIS Hub, OGC Records/CSW, collection-level STAC, and SDMX clients preserve family-specific source metadata.
6. ceres export --format parquet streams PostgreSQL records, filters noise, flattens metadata, flags cross-portal title matches, and writes compressed Parquet plus checksummed reports.

The data.europa.eu refresh was intentionally stopped after resource enrichment reached approximately half the exported portal rows so this snapshot would not delay Ceres 0.7.0. The export contains 712,481 data.europa.eu records, of which 366,307 (51.4%) include resource metadata. Completing the remaining enrichment is tracked in Ceres issue #254 for the next release.

Curation

• Noise filtering: 81,766 rows removed (short/noise titles and empty descriptions)
• Duplicate flagging: 1,354,529 rows marked; records are retained and no canonical entity resolution is claimed
• Alias normalization: known mirror or alternate endpoints can share a canonical portal identity
• Metadata flattening: nested source fields and resource metadata are normalized into the published schema

The duplicate method and version are recorded under duplicate_detection in metadata.json.

Update and provenance

Snapshot ceres-20260819-884e6da7b4b0 was generated on 2026-08-19 by Ceres 0.7.0 at commit 2583fcf. Relative to ceres-20260715-ed0c345e8663, it has 183,625 added, 172,349 changed, 2,613 removed, and 2,389,047 unchanged records. See changelog.md for the per-portal breakdown.

Considerations

Known biases and limitations

• Large aggregators dominate the index: data.europa.eu contributes 26.0% and catalog.data.gov 14.6% of rows.
• The partial data.europa.eu refresh means resource coverage is materially better than v5 but not complete.
• 49.3% of rows are flagged as possible cross-portal title duplicates, especially because aggregators re-list member-portal records.
• Metadata quality, vocabulary, timestamps, and license conventions vary by source; only 31.8% of rows have a non-empty license.
• SPARQL, STAC, OGC, and SDMX records may have fewer normalized fields than CKAN or Socrata records.
• Exporter language and source-type annotations are incomplete for legacy configurations, but original source URLs and metadata are retained.

Ethical considerations

This dataset contains public catalog metadata from government and institutional portals. It does not intentionally contain the underlying data files. Source licenses vary; consumers must follow the license and terms attached to each source record.

Additional information

License

This aggregate dataset and its tooling are released under Apache 2.0. Underlying source metadata may carry separate open-data licenses recorded per row where available.

Citation

@misc{ceres-open-data-index-2026,
  title={Ceres Open Data Index},
  author={Andrea Bozzo},
  year={2026},
  url={https://github.com/AndreaBozzo/Ceres},
  note={2,745,021 records from 567 portal exports, snapshot 2026-08-19}
}

Links

• Ceres on GitHub
• Ceres documentation