# Public GIS source acquisition evidence — method

This edition compares 20 fixed-roster source families using 20 acquisition attributes. It describes the documentation inspected on 24 October 2026 in America/Denver; the exact UTC observations fall on 25 October and are retained per source. A public metadata page, visible download link or documented API is not evidence that a download, sign-in, paid service or API call succeeded.

## How the rows were compiled

The first five profiles were checked against fresh primary documentation; the remaining 15 use the same fields. Each row identifies its publisher, source and relevant product family, formats, coverage, update pattern and access conditions. The source ledger records the requested URL, final URL when returned, observation time, request status and source-body or observation hash. Failed requests remain failed even when a different method later opened the page. HTML documents and PDF manuals were read; source datasets were not downloaded or rehosted.

Short identifying excerpts remain in `source-ledger.json` under `terms_quotes`; row `licence_quote_ids` link to them. They are not a replacement for the full terms. The linked source and observation date establish its context. NWI and NOAA Digital Coast did not supply an exact dataset-wide licence grant in the inspected pages; their quote-ID lists remain empty, and the rows require checking the individual dataset’s terms. A portal’s general copyright notice is not treated as a licence for every partner dataset. No legal clearance or interpretation is provided.

## Comparability

Rows represent distinct discovery families, not 20 independent agencies or 20 uniformly licensed files. NASA Earthdata, NOAA Digital Coast and GeoGratis aggregate products with different owners, coverage and access routes. Copernicus GLO products and restricted EEA-10 access are distinguished. ArcticDEM public-release exceptions, GISCO’s stated non-commercial limitation and Overture’s mixed theme/source licences remain visible. Archived NHD availability does not imply active NHD maintenance.

`Not established in inspected sources` means no supported value was found in this bounded inspection. It does not mean the feature is absent. No availability percentage, throughput, uptime, full-download completeness or usage quota was measured. Update descriptions report the provider’s documented cadence and are not a longitudinal monitoring result.

## Finder labels

The five filters use controlled geography, theme, format, licence and access labels stored in each row. A selected value must match one label within that dimension; the five dimensions combine with AND. Broad catalogue labels help discovery but do not expand a product’s coverage or permissions. The finder preserves all rows as a plain HTML table when JavaScript is unavailable and uses no network calls to filter them. Browser execution evidence belongs to the separate finder observation record, not to these documentation findings.

## Files and reuse

`index.json` is the canonical structured compilation; `index.csv` is its documented flattened view. `source-ledger.json` retains source observations, and `hashes.txt` provides SHA-256 checksums. The original compiled annotations are licensed **CC BY 4.0**. Source datasets, documentation, trademarks and software retain their own terms. No source dataset is redistributed, and no row or position is sponsored or sold.

## E1 terms and typography correction

The `licence` field names the licence or documented status. Detailed scope remains separate, and shared USGS, Copernicus, PGC, GEBCO and NASA policy wording is consistent across the two compilations where the same terms apply. Unknown blanket rights stay unknown. Dated publisher evidence supports the labels; this edit does not establish legal clearance or execute data acquisition. Existing source observations remain dated as originally opened.

Letter–digit errors came from authored Python string literals in the P3 builder, then propagated through JSON into tables. The E1 renderer reads the corrected canonical records. Its validation checks every prose field and rendered table against a documented exact-token allowlist; it does not insert spaces into URLs, identifiers, versions or quoted source text. The earlier generator and runs remain unchanged.