# Ground Site Catalog

The Ground Site Catalog is a global screening dataset for locating satellite
ground infrastructure. It combines candidate search areas and retained site
alternatives with terrain, buildability, exclusion and source-provenance
fields.

The current public release is `2026-08-21-global-terrain-v2`. These records are
screening evidence. They are not a substitute for a site survey, permitting
review, land access confirmation or engineering due diligence.

## Access

- [Browse every published file and download the complete dataset](https://data.dynamikorbits.com/products/ground-site-catalog#product-detail)
- [Open the streaming map in GeoLibre](https://web.geolibre.app/?url=https%3A%2F%2Fdata.dynamikorbits.com%2Foptical-ground-siting%2F2026-08-21-global-terrain-v2%2Fgeolibre%2Fcandidates-dd07ae1b5d6f15c8ea59%2Fground-site-catalog.geolibre.json)
- [Download the complete release as TAR](https://data.dynamikorbits.com/optical-ground-siting/downloads/2026-08-21-global-terrain-v2.tar)
- [Request 175 recommendations as GeoParquet](https://data.dynamikorbits.com/v1/selections?count=175&release=latest&format=parquet)

The selection API accepts a `count` from 1 to 1,000, a `release` identifier or
`latest`, and `format=parquet`, `csv`, or `geojson`.

```text
GET https://data.dynamikorbits.com/v1/selections?count=175&release=latest&format=parquet
```

## Contents

The Contents browser above is the authoritative inventory for the current
release. Its main entries are:

| Path | Purpose |
| --- | --- |
| `candidates_res5.parquet` | One screening record for each global H3 resolution-5 search area. |
| `alternatives_res9/` | Retained fine-grained alternatives, partitioned for analytical access. |
| `data_dictionary.csv` | Field names, types and definitions. |
| `ATTRIBUTION.md` | Upstream sources, rights and attribution requirements. |
| `manifest.json` | Artifact sizes, SHA-256 digests and release provenance. |
| `geolibre/ground-site-catalog.pmtiles` | Range-streamable vector-tile view for interactive maps. |
| `geolibre/ground-site-catalog.geolibre.json` | Ready-to-open GeoLibre project. |
| `downloads/` | Complete offline release archive. |

Every file has a direct public URL and supports `GET` and `HEAD`. Large
streaming assets support HTTP byte ranges.

## Choosing a distribution

Use GeoParquet for analysis and bulk processing. It preserves the complete
analytical records and is the canonical numerical distribution.

Use PMTiles through the GeoLibre project for interactive viewing. PMTiles is a
visualization derivative designed to be streamed by HTTP range requests; it
does not replace the analytical GeoParquet files.

Use the selection API when an application needs a bounded number of published
recommendations rather than the whole dataset. Use the TAR archive for an
offline copy of the complete release.

## Provenance and integrity

The release is immutable. `manifest.json` records every artifact's path, byte
size and SHA-256 digest. Publication is considered successful only after the
objects have been read back from Cloudflare R2 and verified against those
digests.

The source code and data-contract documentation live in the
[optical-ground-siting repository](https://github.com/DynamikOrbits/optical-ground-siting).
This README is maintained in that repository and published as a versioned
snapshot with the dataset page.

## License, sources and attribution

Redistribution conditions can differ between upstream source families. Consult
the release's `ATTRIBUTION.md` and manifest before redistributing derived
extracts. Publishing a combined screening record does not remove upstream
licence or attribution obligations.

## Limitations

- The catalogue prioritizes global, repeatable screening; it is not a locally calibrated site assessment.
- Missing or coarse source evidence remains a limitation and must not be interpreted as proof of suitability.
- Candidate coordinates do not establish ownership, access, permitting status or constructability.
- The streaming tiles simplify the analytical release for display and should not be used as the source for exact analysis.