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Ontology crosswalk

Not commercially licensable. LEHD Commuter Flows is outside the Commercial All-access license; no commercial or paid tier is offered for it.

LEHD Commuter Flows — Ontology Crosswalk

Schema: pending (AXC-11 — schemas/lehd-flows/v1.0.md) Target standards: U.S. Census TIGER/Line + FIPS codes, OGC GeoJSON (RFC 7946), DCAT-US v3.0, DDI-Lifecycle (statistical metadata) Authority: U.S. Census Bureau, OGC, IETF Status: FAIR-aligned, Census-native field mapping Dataset license status: no governed research release — no research license resolves for this family · origin-destination flows are not commercially licensable; outside the Commercial All-access license (LEHD Workplace Jobs, the LODES WAC family, is the covered LEHD family)


1. Why Census TIGER + FIPS

LEHD Origin-Destination Employment Statistics (LODES) are U.S. Census Bureau products. Every consuming pipeline in academia, urban planning, and transportation expects Census-native identifiers — FIPS codes for states/counties/tracts/block groups/blocks and TIGER/Line geometries as the spatial reference. Codex preserves Census fidelity and adds H3 as an interoperability layer without breaking the primary identifiers.


2. Dataset-level (DCAT-US v3.0)

DCAT-US field Value
dct:identifier urn:axiom:codex:dataset:lehd-flows:v1.0.0
dct:title "Axiom LEHD Origin-Destination Commuter Flows Dataset"
dct:description "LEHD LODES v8 origin-destination commuter flows normalized to H3 resolution 8 cells with pre-computed accessibility indices."
dcat:keyword ["lehd", "lodes", "commuter-flows", "origin-destination", "census", "labor-mobility"]
dcat:theme ["http://publications.europa.eu/resource/authority/data-theme/ECON", "...SOCI"]
dct:source https://lehd.ces.census.gov/data/lodes/
dct:license none (no governed research license resolves)

3. Field-level crosswalk → Census LEHD LODES v8

Codex field LODES equivalent Notes
origin_h3 derived from w_geocode (15-char block FIPS) H3 res 8 centroid of block geometry
destination_h3 derived from h_geocode same
origin_block_fips w_geocode Retained as Census-native identifier
destination_block_fips h_geocode Retained
worker_count S000 Total jobs
worker_count_lt30k SE01 Jobs with earnings < $1250/month
worker_count_30to60k SE02 Jobs with earnings $1251–$3333/month
worker_count_gt60k SE03 Jobs with earnings > $3333/month
income_band derived from SE01/02/03 Codex-published enum: low, mid, high
job_sector_naics SI01–SI03 Sector-aggregated counts
metro_slug derived Metro FIPS → slug
lehd_year file name / metadata e.g. 2023
normalization_version fixed 1.0.0

3.1 Codex extensions

Codex field Notes
accessibility_index Codex-computed accessibility score per origin-destination H3 pair. Methodology details are not documented in this public crosswalk.
distance_km Centroid-to-centroid km between H3 cells
h3_neighbor_rank k-ring distance from origin to destination (0 = same cell)

4. Spatial crosswalk → OGC GeoJSON

Per RFC 7946, each flow is a LineString Feature when queried spatially:

{
  "type": "Feature",
  "geometry": {
    "type": "LineString",
    "coordinates": [
      [-87.65, 41.88],  // origin H3 centroid
      [-87.62, 41.85]   // destination H3 centroid
    ]
  },
  "properties": {
    "origin_h3": "882664c2a9fffff",
    "destination_h3": "882664c2b5fffff",
    "worker_count": 218,
    "income_band": "mid",
    "accessibility_index": 0.042
  }
}

5. Statistical metadata → DDI-Lifecycle (brief)

For academic users, a DDI-L 3.3 StudyUnit sidecar describes:

  • StudyUnit.universe: "U.S. private-sector covered employment"
  • StudyUnit.coverage.spatial: "United States, 2002–current year"
  • StudyUnit.coverage.temporal: LODES year
  • StudyUnit.methodology: reference to LEHD QWI methodology paper
  • StudyUnit.variables[]: full S000, SE0n, SI0n list with Census-native definitions

Full DDI sidecar emitted at /datasets/lehd-flows/v1.0.0/ddi.xml.


6. FAIR compliance

Principle Status
F ✅ (Census-native FIPS preserved + DCAT-US + DDI)
A ✅ (HTTPS Parquet + NDJSON)
I ✅ (LODES columns preserved; H3 layered on top)
R ⚠️ (no resolvable license yet; documented Huff methodology)

7. Deviations

  • Noise infusion is inherited. LODES applies noise infusion to protect confidentiality; Codex does not attempt to reverse. All counts carry the LODES noise properties.
  • Block-level granularity collapsed. We publish H3 cell pairs, not FIPS block pairs, as the primary key. Block pairs are retained as supplementary columns for academic users but deduplicated at the H3 level by default.

8. Changelog

  • v1.0 (2026-04-16) — Initial crosswalk. AXC-11 schema spec pending.